Download workshop on laser-matter interaction 2010

2nd INTERNATIONAL
WORKSHOP ON LASER-MATTER
INTERACTION 2010
September 13-17, 2010
Porquerolles, France
Book of abstracts
Edited 25 June 2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
Dear Participants
It is a real pleasure to welcome you to this second edition of the Workshop on Laser-Matter
Interaction. After Luminy in 2008, we are pleased to see that this meeting is growing in size,
becoming international, and attracting new generations of scientists. This second international
edition will hopefully broaden the community and strengthen ties between various laboratories with
worldwide reputation. The island of Porquerolles was chosen for its beauty but also for the
convenient facilities offered by the IGESA housing.
We are 63 registered participants and received 65 contributions. Among those, 44 have been
selected for oral sessions and 16 for the poster session. The sessions have been organized into three
30 minutes tutorials, forty one 20 minutes talks and sixteen posters. We tried to mostly follow the
participants’ wishes, but we were also concerned with keeping a certain coherence between all the
topics addressed within each session. Tutorials have been selected in order to emphasize “hot
topics”, such as warm dense matter and radiative shocks, ultra-high intensities and particle
acceleration, femtosecond laser filamentation and related applications.
We willingly leave the beginning of the afternoons free (between 14:00 and 17:00), so that
everybody can enjoy the island by walking or riding a bicycle, by contemplating the Mediterranean
depths, or even by tasting local wines.
We would like to thank the generous organizations that contributed either financially or by other
means to the workshop, namely, the CEA-DAM at Bruyères-le-Châtel and several of its
departments, the Laser-Plasmas Institute in France, and the Max-Planck Institute in Germany.
We hope that you – and your family for some of you – will enjoy this meeting and your stay at
Porquerolles.
Organizing committee
Luc Bergé
Christophe Rousseaux
Stefan Skupin
Page 2
Scientific committee
CEA France
CEA France
MPI-PKS Germany
WLMI-2010
Patrick Mora
J.C. Saut
D. Skryabin
G. Steinmeyer
V. Tikhonchuk
France
France
U.K.
Germany
France
WORKSHOP ON LASER-MATTER INTERACTION 2010
Program
Monday, September 13
19:15
Welcome reception
Tuesday, September 14
08:45-09:00...........Opening, L. Bergé
09:00-10:30 ....... Session Warm Dense Matter & AstroLab
Chair: P. Mora
09:00-09:30...........Tutorial: R. P. Drake “Laboratory astrophysics using HERCULES, Omega and NIF”
09:30-09:50
B. Loupias “Laboratory astrophysics using intense lasers“
09:50-10:10
S. Brygoo “Measurements of the equation of state of hydrogen/helium mixtures under deep
planetary conditions “
10:10-10:30
T. Vinci “Numerical and experimental study of quasi-isentropic compression by Laser Irradiation “
10:30-11:00
Coffee break
11:00-12:30 ....... Session Femtosecond Filamentation
Chair: L. Bergé
11:00-11:30...........Tutorial: O. Kosareva “Polarization rotation due to femtosecond filamentation in an atomic gas”
11:30-11:50
A. Aceves “Modeling UV filamentation“
11:50-12:10
J. Kasparian “Higher-order Kerr terms allow ionization-free filamentation in gases“
12:10-12:30
S. V. Chekalin “Interference effects in supercontinuum conical emission upon filamentation of a
femtosecond laser pulse in condensed matter“
12:30
Lunch
17:00-18:40 ....... Session Ultrafast Microprocessing
17:00-17:20
17:20-17:40
17:40-18:00
18:00-18:20
18:20-18:40
Chair: J. Kasparian
F. Courvoisier “Ultrafast laser micro/nano processing of high aspect ratio channels in dielectrics
with Bessel beams“
V. Mezentsev “Single process femtosecond laser microfabrication -- novel technology in modern
photonics: meticulous experiments and serious numerics“
S. Guizard “Femtosecond ablation of dielectrics : time resolved studies of excitation mechanisms“
T. Itina “Ultra-short laser interactions: insights from numerical modeling“
Yu. Geints “Explosive evaporation of large water droplet irradiated by ultrashort laser pulses“
Wednesday, September 15
08:40-10:00 ....... Session Applied Mathematics
08:40-09:00
09:00-09:20
09:20-09:40
09:40-10:00
10:00-10:30
Chair: E. A. Kuznetsov
D. Lannes “Short pulses approximation in dispersive media“
E. Lorin “A nonlinear quantum optics model for laser-gas interaction in some extreme regimes“
E. Dumas “High frequency behaviour of the Maxwell-Bloch model with relaxations: Convergence
to the Schrödinger-Boltzmann system”
R. Sentis “On three-wave coupling system and the related simulations of the Brillouin
Backscattering for ICF target”
Coffee break
WLMI-2010
Page 3
WORKSHOP ON LASER-MATTER INTERACTION 2010
10:30-12:20 ....... Session Ultra-High Intensities
Chair: B. Afeyan
10:30-11:00 .......... Tutorial: P. Mora “Plasma expansion into a vacuum and ion acceleration”
11:00-11:20
V. Yu. Bychenkov “Towards improving the quality of laser-produced particle sources“
11:20-11:40
S. Ter-Avetisyan “Laser-based ion acceleration: new progress and perspectives for application“
11:40-12:00
A. A. Andreev “Laser ion acceleration in shaped mass-limited targets“
12:00-12:20
L. Gremillet “Recent results on unstable relativistic electron transport into dense plasmas“
12:30
Lunch
17:00-19:00 ....... Poster Session
Thursday, September 16
09:00-10:20 ....... Session Pulse Compression and Nonlinear Propagation
Chair: O. Kosareva
09:00-09:20
09:20-09:40
09:40-10:00
10:00-10:20
G. Steinmeyer “Single and multiple filamentary self-compression scenarios“
E. Constant “Ionization induced post compression of high energy pulses“
M. Bache “Few-cycle energetic femtosecond pulses in the visible and near-IR by using cascaded
quadratic soliton compression“
V. Tosa “Pulse propagation effects in high order harmonic generation by mid-infrared source“
10:20-11:00
Coffee break
11:00-12:20 ....... Session Supercontinuum Generation and Frequency Conversion
Chair: G. Steinmeyer
11:00-11:20
11:20-11:40
11:40-12:00
12:00-12:20
W. Krolikowski “Parametric wave mixing in nonlinear disordered media“
A. V. Gorbach “Nonlinear photonics in silicon nano-structures“
J. Herrmann “Generation of high-power supercontinuum and tunable sub-10-fs VUV pulses in
photonic crystal fibers“
M. Taki “Observation of extreme temporal events in CW-pumped supercontinuum“
12:30
Lunch
17:00-18:40 ....... Session Inertial Confinement Fusion
17:00-17:20
17:20-17:40
17:40-18:00
18:00-18:20
18:20-18:40
19:30
Page 4
Chair: R. P. Drake
P. Michel “Analysis and review of laser plasma interactions in experiments on the National Ignition
Facility“
B. Afeyan “Spike Trains of Uneven Duration and Delay: STUD pulses for the control of nonlinear
optical instabilities in laser-matter interactions“
D. Benisti “Nonlinear properties of an electron plasma wave and application to stimulated Raman
scattering“
P. Loiseau “Realistic modelling of laser-plasma interaction in hot plasmas: toward a predictive
tool?“
P. E. Masson-Laborde “Progress in modeling and understanding of parametric instabilities in
laser-plasma-interaction“
WLMI Conference Dinner
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
Friday, September 17
08:40-10:20 ....... Session X, VUV and THz Sources
Bychenkov
08:40-09:00
09:00-09:20
Chair: V. Yu.
09:40-10:00
10:00-10:20
C. Courtois “MeV X-ray source production on Omega EP laser facility “
J. Liu “Fast electrons and high order harmonics generation from ultraintense laser-plasma
interaction“
I. Babushkin “Modeling of THz emission from plasma-generating femtosecond laser pulses with
unidirectional Maxwell equation in plasma spots and in guided geometries“
S. Le Pape “X-ray Thomson scattering of isochorically proton heated Boron Nitride“
F. Dorchies “Time-resolved XANES to probe the structure of Warm Dense Matter“
10:20-10:50
Coffee break
09:20-09:40
10:50-12:10 ....... Session Self-focusing and Singular Dynamics
10:50-11:10
11:10-11:30
11:30-11:50
11:50-12:10
Chair: S. Skupin
E. A. Kuznetsov “Collapse as a process of pulse shortening“
P. M. Lushnikov “Statistics of strong optical turbulence“
H. Leblond “Few-cycle optical pulse: Collapse and light bullets“
N. Rosanov “Extreme optical pulse compression and frequency transformation “
12:10-12:30...........Closing, Organizing Committee
12:30
Lunch
15:00
Departure
WLMI-2010
Page 5
WORKSHOP ON LASER-MATTER INTERACTION 2010
Oral contributions
O 1:
O 2:
O 3:
O 4:
O 5:
O 6:
O 7:
O 8:
O 9:
O 10:
O 11:
O 12:
O 13:
O 14:
O 15:
O 16:
O 17:
O 18:
O 19:
O 20:
O 21:
O 22:
O 23:
O 24:
O 25:
O 26:
O 27:
O 28:
O 29:
O 30:
O 31:
O 32:
O 33:
Laboratory astrophysics using HERCULES, Omega, and NIF ............................... 12
Laboratory astrophysics using intense lasers ......................................................... 13
Measurements of the equation of state of hydrogen/helium mixtures under deep
planetary conditions................................................................................................ 14
Numerical and Experimental Study of Quasi-Isentropic Compression by Laser
Irradiation ............................................................................................................... 15
Polarization Rotation due to Femtosecond Filamentation in an Atomic Gas .......... 16
Modeling UV Filamentation .................................................................................... 17
Higher-order Kerr terms allow ionization-free filamentation in gases ..................... 18
Interference effects in supercontinuum conical emission upon filamenttation of a
femtosecond laser pulse in condensed matter ....................................................... 19
Ultrafast laser micro/nano processing of high aspect ratio channels in dielectrics
with Bessel beams.................................................................................................. 20
Single process femtosecond laser microfabrication — novel technology in modern
photonics: meticulous experiments and serious numerics...................................... 21
Femtosecond ablation of dielectrics : time resolved studies of excitation
mechanisms ........................................................................................................... 22
Ultra-short laser interactions: insights from numerical modeling ............................ 23
Explosive Evaporation of Large Water Droplet Irradiated by Ultrashort Laser Pulses
............................................................................................................................... 24
Short pulses approximation in dispersive media .................................................... 25
A nonlinear quantum optics model for laser-gas interaction in some extreme
regimes................................................................................................................... 26
High Frequency Behaviour of the Maxwell-Bloch Model with Relaxations:
Convergence to the Schrödinger-Boltzmann System ............................................. 27
On three-wave coupling system and the related simulations of the Brillouin
Backscattering for ICF target. ................................................................................. 28
Plasma expansion into a vacuum and ion acceleration .......................................... 29
Towards improving the quality of laser-produced particle sources ......................... 30
Laser-based ion acceleration: new progress and perspectives for application ....... 31
Laser ion acceleration in shaped mass-limited targets ........................................... 32
Recent results on unstable relativistic electron transport into dense plasmas ........ 33
Single and multiple filamentary self-compression scenarios .................................. 34
Ionization induced post compression of high energy pulses................................... 35
Few-cycle energetic femtosecond pulses in the visible and near-IR by using
cascaded quadratic soliton compression ................................................................ 36
Pulse propagation effects in high order harmonic generation by mid-infrared source
............................................................................................................................... 37
Parametric wave mixing in nonlinear disordered media ......................................... 38
Nonlinear photonics in silicon nano-structures ....................................................... 39
Generation of high-power supercontinuum and tunable sub-10-fs VUV pulses in
photonic crystal fibers ............................................................................................. 40
Observation of extreme temporal events in CW-pumped supercontinuum............. 41
Analysis and review of laser plasma interactions in experiments on the National
Ignition Facility ........................................................................................................ 42
Spike Trains of Uneven Duration and Delay: STUD pulses for the Control of
Nonlinear Optical Instabilities in Laser-Matter Interactions* ................................... 43
Nonlinear properties of an electron plasma wave and application to stimulated
Raman scattering ................................................................................................... 44
Page 6
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 34: Realistic modelling of laser-plasma interaction in hot plasmas: toward a predictive
tool? ........................................................................................................................ 45
O 35: Progress in modeling and understanding of parametric instabilities in laser-plasmainteraction ............................................................................................................... 46
O 36: MeV X-ray source production on Omega EP laser facility....................................... 47
O 37: Fast electrons and high order harmonics generation from ultraintense laser-plasma
interaction ............................................................................................................... 48
O 38: Modeling of THz emission from plasma-generating femtosecond laser pulses with
unidirectional Maxwell equation in plasma spots and in guided geometries ........... 49
O 39: X-ray Thomson scattering of isochorically proton heated Boron Nitride .................. 50
O 40: Time-resolved XANES to probe the structure of Warm Dense Matter .................... 51
O 41: Collapse as a process of pulse shortening.............................................................. 52
O 42: Statistics of strong optical turbulence ...................................................................... 53
O 43: Few-cycle optical pulse: Collapse and light bullets ................................................. 54
O 44: Extreme Optical Pulse Compression and Frequency Transformation ..................... 55
WLMI-2010
Page 7
WORKSHOP ON LASER-MATTER INTERACTION 2010
Posters contributions
P 1:
P 2:
P 3:
P 4:
P 5:
P 6:
P 7:
P 8:
P 9:
P 10:
P 11:
P 12:
P 13:
P 14:
P 15:
P 16:
Advances in Optical Mixing Techniques for the Effective Control of Parametric
Instabilities in Laser-Produced Plasmas ................................................................. 56
Nonlinear Bloch equations for laser-quantum dot interactions ............................... 58
Scaling laws in laboratory astrophysics .................................................................. 59
Terahertz radiation from gas plasma, generated by linearly polarized femtosecond
pulses ..................................................................................................................... 60
Terahertz mode dynamics in beta- barium borate crystals ..................................... 61
Radiating Solitary Waves in Photonic Band Gap .................................................... 62
Paths towards the generation of monochromatic ion beams .................................. 63
All-optical steering of light via spatial Bloch oscillations in a gas of three-level atoms
............................................................................................................................... 64
Theory of Plasmon-Enhanced High-Harmonic Generation in the Vicinity of Metal
Nanoparticles ......................................................................................................... 65
Self-compression of ultrashort pulses in media with negative third order nonlinearity
............................................................................................................................... 66
Coupling between Kerr-induced filamentation and stimulated Brillouin scattering in
silica ....................................................................................................................... 67
Development of laser plasma instabilities during the interaction of two successive ps
pulses at moderate intensity: space- and time-resolved Thomson scattering
measurements ........................................................................................................ 68
Stability of nonlinear Vlasov waves through Fourier-Hermite discretization ........... 69
Self-Organized Dissipationless Ginzburg-Landau Solitons .................................... 70
Analytical solutions for generalized nonlinear Schrodinger equation ...................... 71
Fast Electron Generation and Transport in Laser-Induced Shock Compressed
Plasmas.................................................................................................................. 72
Page 8
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
Author Index
Aceves A.
Aedy C.
Afeyan B.
Aleksic N. B.
Amadou N.
Amiranoff F.
Andreev A. A.
Atherton L. J.
Babushkin I.
Bache M.
Bandrauk A.
Batani D.
Baton S. D.
Bazzoli S.
Beg F. N.
Béjot P.
Benedetti C.
Benisti D.
Benocci R.
Benuzzi-Mounaix A.
Bergé L.
Bhuyan M. K.
Bidégaray-Fesquet B.
Boehly T. R.
Bond E.
Borghesi M.
Bouquet S.
Bourgade J.-L.
Brambrink E.
Brée C.
Brenner C. M.
Brown C.
Brygoo S.
Bychenkov V. Yu.
Calegari F.
Callahan D. A.
Carpeggiani P.
Carroll D. C.
Casanova M.
Castella F.
Cavet C.
Celliers P. M.
Chawla S.
Chekalin S.V.
Chelkowski S.
Chen Y.
Chin S. L.
Collins G. W.
Compant la Fontaine A.
17
47
43, 56, 68
70
51
68
32
42
49
36
26
72
68, 72
47
72
18
72
33, 44, 68, 69
72
15, 50, 51
34, 49, 66, 67
20
58
14
42
31
13, 59
47
15, 51, 72
34
31
50
14
30
37
42
72
31
45, 46
27
13
14
72
19
26
16
16
14
47
Constant E.
Courtois C.
Courvoisier F.
Coury M.
Davis P. F.
de Rességuier T.
Degert J.
Demircan A.
Depierreux S.
Derrien Th.
Descamps D.
Dewald E. L.
Diaw A.
Divol L.
Dixit S. N.
Dizière A.
Doeppner T.
Dorchies F.
Doria D.
Dormidonov A.E.
Dover N.
Drake R. P.
Drew D.
Dubrouil A.
Dudley J. M.
Dumas E.
Edwards M. J.
Edwards R.
Eggert J.
Ettoumi W.
Fadeev D. A.
Falize E.
Faucher O.
Fedorov N.
Fedotova O.
Festa F.
Fortmann C.
Foster P. S.
Fourcade Dutin C.
Fourment C.
Freysz E.
Furfaro L.
Gaizauskas E.
Galimberti M.
Gallegos P.
Gardner M.
Garnier J.
Gazave J.
Geints Yu. E.
WLMI-2010
35
47
20
72
50
15
61
34
45, 46
23
35
42
63
42
42
13
50
51, 72
31
19
31
12
47
35
20
27
42
47
14
18
60
13, 59
18
22
61
51
50
31
35
72
61
20
62
72
31
47
43
47
24
Page 9
WORKSHOP ON LASER-MATTER INTERACTION 2010
Gizzi L. A.
Glenzer S. H.
Golik S. S.
Goossens J.-P.
Grech M.
Green J. S.
Gregori G.
Gregory C. D.
Gremillet L.
Grobach A. V.
Guizard S.
Guyot F.
Hall T.
Hang C.
Heathcote R.
Henin S.
Herrmann J.
Hertz E.
Higginson D. P.
Hinkel D. E.
Hochhaus D.
Honrubia J. J.
Hueller S.
Hulin S.
Husakou A.
Im S.-J.
Itina T. E.
Jacquot M.
Jafer R.
Jarrot L. C.
Jeanloz R.
Kabanov A. M.
Kandidov V.P.
Kasparian J.
Khasanov O.
Kiefer T.
Klimentov S.
Kline J. L.
Koenig M.
Köhler C.
Kolobov M.
Kompanets V.O.
Konotop V. V.
Kosareva O. G.
Köster P.
Kovacs K.
Kremer D.
Kritcher A. L.
Krolikowski W.
Kudlinski A.
Kuramitsu Y.
Kuznetsov E. A.
Page 10
Kyrala G. A.
72
Labate L.
42, 50
Labaune Ch.
24
Lacourt P. A.
45
Lancaster K.
63
Landen O. L.
31
Landoas O.
50
Lannes D.
13
Lavorel B.
33, 44, 63, 68, 69
Le Pape S.
39
Leblond H.
22
Lefebvre E.
15
Lévy A.
51
Li R.
64
Lindl J. D.
72
Liu J.
18
Loiseau P.
40, 49, 65
Lorin E.
18
Loriot V.
72
Loubeyre P.
42
Loupias B.
50
Louvergneaux E.
72
Lushnikov P. M.
43, 45, 46
MacGowan B. J.
72
MacKinnon A. J.
40, 65
Makarov V. A.
40, 65
Marceau C.
23
Mardirian M.
20
Mardirian M. M.
72
Marion D.
72
Masson-Laborde P.-E.
14
Mastrosimone D.
24
Mauger S.
19
Mazevet S.
18
Mazevetv S.
61
McKenna P.
63
McPhee A. G.
22
Meezan N. B.
42, 68
Mével E.
13, 15, 51, 72
Mezentsev V.
49, 66
Michaut C.
41
Michel P.
19
Mihalache D.
64
Mikaberidze A.
16
72
Mironov V. A.
37
Montgomery D. S.
54
Moody J. D.
50
Mora P.
38
Morard G.
41
Morice O.
13
Morita T.
52
Mouskeftaras A.
WLMI-2010
42
72
46
20
72
42, 50
47
25
18
50
54
33, 47, 63
51
48
42
48
45, 46, 68
26
18
14
13, 68
41
53
42
72
16
16
43
56
45
45, 46
47
67
51
15
31, 72
72
42
35
21
13, 59
42
54
63
60
68
42
29
15
44
13
22
WORKSHOP ON LASER-MATTER INTERACTION 2010
Mussot A.
Najmudin Z.
Nazarov W.
Neely D.
Negro M.
Neumayer P.
Nicolaï Ph.
Nuter R.
Oberlé J.
Oshlakov V. K.
Palmer C. A. J.
Panov N. A.
Pasley J.
Perez F.
Perezhogin I. A.
Pesme D.
Petit S.
Petit Y.
Peyrusse O.
Philippe F.
Pien G.
Pikuz S.
Povarnitsyn M. E.
Prasad R.
Quinn K. E.
Rabec Le Glohaec M.
Ramis R.
Ravasio A.
Recoules V.
Regan C.
Rhee Y.
Ribeyre X.
Richetta M.
Romagnani L.
Rosanov N. N.
Rousseaux C.
Rozmus W.
Rusetsky G.
Sakawa Y.
Santos J. J.
Savel’ev A. B.
Savickas A.
Schlenvoigt H.-P.
Schneider M. B.
Schreiber J.
Schurtz G.
Sentis R.
Serres F.
Sgattoni A.
Shcheblanov N. S.
Siminos E.
41
31
13, 72
31
37
50
72
63
61
24
31
16
72
72
16
45, 46
35
18
51
68
47
13
23
31
31
72
72
13, 50, 51
51
72
72
13, 72
72
31
55
43, 45, 68
46
61
13
72
16
62
72
42
31
72
28
72
72
23
44, 69
Simons A.
Skarka V.
Skopina O.V.
Skupin S.
Smetanina E.O.
Spaulding D.
Spindloe C.
Stagira S.
Staliunas K.
Steinmeyer G.
Stoeckl C.
Streeter M. J. V.
Strozzi D. J.
Suter L. J.
Takabe H.
Taki M.
Tatarinova L. T.
Ter-Avetisyan S.
Teychenne D.
Thomas C. A.
Tikhonchuk V. T.
Tosa V.
Town R. P. J.
Tresca O.
Vaisseau X.
Vauzour B.
Veltcheva M.
Vermersch B.
Vidal S.
Vieillard T.
Vinci T.
Vladimirova N.
Volpe L.
Vozzi C.
Wang C.
Wang T.
Wang W.
Widmann K.
Williams E. A.
Wise F. W.
Wolf J.-P.
Woolsey N. C.
Xia C.
Xu Z.
Yahia V.
Yuan S.
Zemlyanov A. A.
Zeng H.
Zepf M.
Zhou B.
WLMI-2010
47
70
19
34, 49, 63, 66, 67
19
14
72
37
62
34
47
31
44
42
13
41
71
31
45
42
63
37
42
31
72
72
72
33
61
18
15
53
72
37
48
16
48
42
42
36
18
13
48
48
72
16
24
16
31
36
Page 11
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 1:
Laboratory astrophysics using HERCULES, Omega, and NIF
R. Paul Drake
University of Michigan - USA
Abstract:
This talk will discuss our work in laboratory astrophysics using intense lasers at the
University of Michigan. Our focus is on dynamical processes present in astrophysics that
can be produced in the laboratory. We have used the HERCULES laser to explore the
filamentation of relativistic electron beams in plasmas, a process that represents on step in
the ultimate emission of detectable radiation from relativistic jets. We have use the Omega
laser very extensively, in two directions Our focus in radiation hydrodynamics has been the
study of radiative shock waves, in which radiative energy transfer produces structure in
shock waves that differs dramatically from the structure in more-familiar, purely
hydrodynamic cases. To do this, we launch a piston of Be plasma at ~ 200 km/s into a
shock tube filled with Xe gas at near atmospheric pressure. This produces a shock wave
with a Mach number of about 600, in which most of the thermal energy created by the
shock transition is converted to radiation. By means of experiments, theory, advances in
diagnostics, computer simulations, and uncertainty quantification we are working to better
understand the structure of these systems. Looking ahead, we a turning our attention to
radiative reverse shocks, one component of the structure that develops naturally in
cataclysmic binary stars. Our focus in high-energy-density hydrodynamics is the
fundamental instabilities of compressible, accelerating, ionizing systems. We see novel
effects in both the Rayleigh-Taylor instability and the Kelvin Helmholtz instability, very
likely reflecting complex properties of high-energy-density systems not present in
traditional fluids. Issues in understanding observations of supernovae directly motivate our
Rayleigh-Taylor experiments. Combining both these thrust areas, we are doing
experiments at the National Ignition Facility for radiation-shock-mediated, hydrodynamicinstability experiments. These experiments are relevant to phenomena in red supergiant
stars. Many collaborators, to be acknowledged in the talk, have been essential to this
work.
The work to be discussed is funded by the NNSA-DS and SC-OFES Joint Program in
High-Energy-Density Laboratory Plasmas, by the National Laser User Facility Program in
NNSA-DS and by the Predictive Sciences Academic Alliances Program in NNSA-ASC.
The corresponding grant numbers are DE-FG52-09NA29548, DE-FG52-09NA29034, and
DE-FC52-08NA28616.
Page 12
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 2:
Laboratory astrophysics using intense lasers
B. Loupias1 & A. Ravasio2
1
2
CEA-DAM F-91297 Arpajon, FRANCE
Laboratoire LULI, Ecole Polytechnique, Palaiseau, FRANCE
E, Falize1, C. D. Gregory2, A. Dizière2, M. Koenig2, C. Michaut3, C. Cavet3,S. Bouquet1,
X. Ribeyre4, H. Takabe5, Y. Sakawa5, Y. Kuramitsu5, T. Morita5, N. C. Woolsey6,
W. Nazarov7, S. Pikuz8
3
LUTH, Observatoire de Paris, CNRS, Université Paris-Diderot, 92190 Meudon, France
Centre Lasers Intenses et Applications (CELIA), UMR 5107 Université Bordeaux 1, 351,
cours de la Liberation, 33405 Talence Cedex FRANCE
5
Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka, Japan
6
Department of Physics, University of York, York, YO10 5DD, UK
7
School of Chemistry, University St Andrews, Purdie Blg, St Andrews, United
Kingdom
8
Joint Institute for High Temperatures of RAS, Izhorskaya 13/19, Moscow,
Russia
4
Thanks to the development of high powered facilities in the last two decades, such as
high-energy lasers and fast magnetic pinch machines (Z-pinch), we can today reach in
laboratory high pressure and high temperature conditions, typical of astrophysical
environments. These progresses, strictly connected with inertial controlled fusion research,
has allowed the emergence of a new discipline, the laboratory astrophysics. This new
class of experimental science, is perfectly complementary to observations, which cannot
always give satisfactory responses, due to an insufficient number of data or a too low
phenomena evolution. The possibility of performing well-designed laboratory simulations to
study astrophysical objects has been demonstrated and can contribute to understand
different processes and to validate complex simulations.
Here we present a series of experiments performed at LULI laboratory. Especially we will
concentrate on our experiments aiming at reproducing astrophysical events by
resemblance or similarity. These include plasma jets and radiative shocks. Both studies
have a deep impact to validate radiative hydrodynamic processes encountered around
young stellar object and supernovae respectively. We will also present a recent
experiment designed to simulate accretion process in magnetic with dwarf.
WLMI-2010
Page 13
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 3:
Measurements of the equation of state of
hydrogen/helium mixtures under deep planetary
conditions
S. Brygoo P. Loubeyre J. Eggert P. M. Celliers D. Spaulding T. R.
Boehly R. Jeanloz and G. W. Collins
Page 14
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 4:
Numerical and Experimental Study of Quasi-Isentropic Compression
by Laser Irradiation
Tommaso Vinci (1)*, Michel Koenig (1), Alessandra Benuzzi Mounaix (1), Erik Brambrink
(1), Stephane Mazevet (2), G. Morard (3), F. Guyot (3), T. de Rességuier (4)
(1) LULI, Ecole Polytechnique, Palaiseau, France
(2) CEA-DAM, Bruyeres-le-Chatel, France
(3) IMPMC, 140 rue de Lourmel, 75005 Paris, France
(4) ENSMA, 1 ave. Clément Ader, 86961 Futuroscope Cedex, France
In this contribution we are presenting recent numerical and experimental studies done in the
framework of a large collaboration (ANR SECHEL) aimed at reproducing earth interior condition
by laser generated isentropic ramp compressions in both iron and aluminum. These conditions
belong to the WDM field of physics (P ~ 1 Mbar and T ~ 1000˚K).
We will report the numerical simulations done with a radiative-hydrodynamic code (MULTI); a
second step has been done to couple these simulations with molecular dynamics to reproduce
microscopic effects in materials. This is a multi-scale approach to simulate matter in these
conditions: the ramp of compression wave of a hydrodynamic simulation is injected as ramp in a
pure molecular dynamics simulation (using massive parallel STAMP code) to study the dynamics
of the atomic structure of materials on strong stress on the same longitudinal and temporal scales of
the experiment (some microns and 1 ns). This a key point to have a complete picture of the
experiment since the hydrodynamic approach fails to understand the underlying mechanism of
phase changes of the material.
On the experimental side, we will present the results of recent experiments done at LULI (France)
and ILE (Osaka, Japan) using two experimental approaches and we will report diagnostic
measurements and connections with numerical simulation.
*E-mail address: [email protected]
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 5:
Polarization Rotation due to Femtosecond Filamentation in an Atomic
Gas
O.G. Kosareva1,, N.A. Panov1, V.A. Makarov1, I.A. Perezhogin1, C. Marceau2, Y. Chen2,
S. Yuan2, T. Wang2, H. Zeng3, A.B. Savel’ev1, and S.L. Chin2
1
International Laser Center & Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia, e-mail: [email protected]
Centre d’Optique, Photonique et Laser (COPL) and Département de physique, de génie physique et d’optique, Université Laval, Québec, Québec
G1V 0A6, Canada
3
State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China
2
The high intensity inside femtosecond light filaments generated by linearly polarized infrared (800 nm)
pulses is sufficient for symmetry breaking in the nonlinear optical response of isotropic gases. In argon, an
initially linearly polarized co-propagating probe pulse at 400 nm becomes elliptically polarized or, for the
specifically chosen conditions, remains linearly polarized but rotated by a certain angle [1-3].
In this paper we show the variation with distance of the polarization ellipticity in a weak linearly
polarized probe beam at 400 nm co-propagating with an 800 nm pump beam, the latter forming a filament in
1 atm argon. The largest rotation angle relative to the initial direction of the probe’s polarization is induced
inside the high-intensity filament core. With propagation distance the nonlinearly rotated probe radiation
diffracts outward into the beam periphery. The experimentally obtained and simulated fluence signals are
compared after an analyzer at the end of the high-intensity filament zone.
In the experiment, a single filament was created by focusing a 1.1 mJ, linearly polarized, 50 fs
Ti:sapphire pump pulse into a gas cell filled with argon. The filament was probed by a second pulse (100 fs,
~1 mJ, 400 nm, polarized at an angle between 0°-90° relative to the pump). After the interaction zone, the
probe pulse was transmitted through an analyzer. In our propagation model the light field complex amplitude
E of both the pump and the probe radiation is represented by two components Ex and Ey in the plane
perpendicular to the propagation direction z. For each of the four light field components we take into account
diffraction, material dispersion, the group velocity walk-off, self- and cross-action due to Kerr nonlinearity at
the frequencies w and 2w, plasma generation and ionization-induced energy loss. The simulated distribution
of the probe light field is projected onto an analyzer and then integrated over the time yielding the fluence
similar to the experiment.
In conclusion, the largest rotation occurs in the central spot of the probe beam corresponding to the
filament core of the pump (Fig.1). With propagation distance, the elliptically polarized and rotated probe
radiation diffracts outwards into the beam periphery while the polarization direction in the core relaxes to
almost the initial orientation.
z = 33 cm
90
30°
Angle, deg.
150
90
60
120
30
180
60
150
0 180
330
210
240
Pump intensity,
TW/cm2
120
90
60
30
0
270
300
z = 33 cm
simulations
experiment
30
polarization
ellipse main axis
0
initial probe
orientation 75o
330 Probe
210
240
270
300
Pump
pump, 800 nm, 1 mJ
probe 400 nm, 1 mJ
0.10
z = 98 cm
0.05
0
0.00
25 50 75 100 125 150
propagation distance z, cm
Probe intensity,
GW/cm2
120
References
z = 98 cm
Fig.1. The two upper polar coordinate plots show the probe pulse fluence
transmitted by the analyzer as a function of the analyzer angle relative to the
initial pump orientation 0°. The lower plot shows peak intensity in both the
pump (squares) and the probe (triangles) pulses.
Page 16
WLMI-2010
[1] P. Béjot et al Opt. Express 16, 7564
(2008).
[2] Y. Chen et al Opt. Lett. 33, 2731
(2008).
[3] C. Marceau et al, Opt. Lett. 34,
1417 (2009).
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 6:
Modeling UV Filamentation
A. Aceves
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 7: Higher-order Kerr terms allow ionization-free filamentation in gases
P. Béjot1,2, W. Ettoumi1, Y. Petit1, J. Kasparian*1, S. Henin1, V. Loriot2, T. Vieillard2,
E. Hertz2, O. Faucher2, B. Lavorel2, and J.-P. Wolf1
(1) Université de Genève, GAP-Biophotonics, 20 rue de l’Ecole de Médecine, 1211 Geneva 4, Switzerland
(2) Laboratoire Interdisciplinaire CARNOT de Bourgogne (ICB), UMR 5209 CNRS-Université de Bourgogne, BP 47870, 21078 Dijon Cedex, France
*email [email protected]
Abstract
Higher-order nonlinear indices, rather than plasma, provide the main defocusing
contribution to filamentation in gases at 800 nm. Developing generalized Miller formulae,
we discuss the generality of this as a function of the laser wavelength.
Filaments are generally considered to stem from a dynamic balance between Kerr focusing and
defocusing by the plasma generated at the non-linear focus. While defocusing by the plasma has
periodically been challenged, no alternative regularizing mechanism was exhibited up to now in
gases. Fifth-order non-linearity has been discussed in this regard, but without knowledge of its
magnitude, preventing quantitative analysis.
Based on the recent experimental measurement of the higher-order Kerr indices n4 through n10 in
N2, O2 and Ar [1,2], we investigate their influence on laser filamentation by numerical simulations.
We show that their values are sufficient to provide the dominant contribution to the defocusing
terms in self-channeling. Their implementation in numerical simulations yields the experimentally
observed plasma density. Moreover, setting the plasma term to zero in the simulations (Fig. 1)
shows that plasma is not required for filamentation. Rather, plasma generation can be considered as
a by-product of the self-guiding of laser filaments in gases at 800 nm [2], which in turn affects the
white-light generation and the conical emission. The observation that ionization almost does not
affect the results of the model provides an opportunity to speed up the numerical simulations and
offers new perspectives for analytic studies of filamentation.
Fig. 1 (a) On-axis intensity and (b) Plasma density as a function of the propagation distance for the classical model
(considering only n2 term of the Kerr index and the plasma defocusing), the full model, and the full model without plasma.
However, when varying the wavelength, the respective values of the higher-order non-linear
indexes and ionization rates vary, so that their respective contributions to defocusing have to be
estimated. Such estimation requires the knowledge of the non-linear indices of arbitrary orders at
any wavelength. We therefore extend the Miller formulae to arbitrary orders. Based on a
perturbative approach, we show that, for any p ≥ 1, the knowledge of the non-linear index of
(2p+1)th order n2p(w0) at frequency w0 and of the dispersion curve for the linear refractive index n0
is sufficient to determine n2p(w) at any frequency.
Based on this new relation, we performed numerical simulations of filamentation over the whole
spectrum from the ultraviolet to the infrared. We show that the contribution of plasma is weak over
the whole visible and near-infrared spectrum, especially for short pulses [4]. On the other hand, in
the ultraviolet where ionization rates are higher, as well as for pulses of a few hundreds of
femtoseconds or more where the plasma has time to accumulate, the defocusing contribution of the
plasma cannot be neglected. Our results renew the vision of filamentation. While the highintensities at play in the filaments indeed ionize the propagation medium, the plasma is, over most
of the spectrum, a by-product rather than a key ingredient of the filamentation process.
References
[1] V. Loriot, et al., “Measurement of high-order Kerr refractive index of major air components”, Opt. Express 16, 13429 (2009)
[2] P. Béjot, et al., “Higher-order Kerr terms allow ionization-free filamentation in air”, Phys. Rev. Lett. 104, 103903 (2010)
[3] W. Ettoumi, Y. Petit, J. Kasparian, J.-P. Wolf, “Generalized Miller formulae”, Opt. Express 18, 6613 (2010)
[4] W. Ettoumi, et al., “Generality of all-Kerr driven filamentation in air”, in preparation
Page 18
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 8: Interference effects in supercontinuum conical emission upon
filamentation of a femtosecond laser pulse in condensed matter
Chekalin S.V.(1), Dormidonov A.E. (2), Kompanets V.O. (1), Smetanina E.O. (2),
Skopina O.V. (2), and Kandidov V.P. (2)
(1)
(2)
Institute of Spectroscopy of the Russian Academy of Sciences, Troitsk, Moscow Region 142190, Russia
M.V.Lomonosov Moscow State University, Physics Department, Moscow, Leninskii Gory, 119992, Russia
It is shown both experimentally and theoretically that interference effects play the key role
in the formation of frequency-angular spectrum of the filament conical emission (CE).
For the first time we investigated experimentally the transformation of the CE frequencyangular spectrum with increasing of the filament length in fused silica and water. The experimental
setup consists of a tunable TOPAS parametric amplifier combined with a regenerative Spitfire
Ti:sapphire amplifier. Experiments were performed by using femtosecond pulses with different
wavelengths, repetition rate was 1 kHz. The original arrangement of our setup enabled slow
variation of the filament length inside the sample without changing of the pulse energy. The length,
location, and structure of glowing filament were registered by a digital camera with a microscope
objective. The broadening of the CE frequency-angular spectrum with increasing of the filament
length was registered, the fine structure of the CE colored rings was discovered in angular
distribution of CE spectral components in lengthy filament, the splitting of the CE rings into the
high-contrast discrete colored rings after refocusing and appearance of the second emitting region
was confirmed.
Computer simulation of laser pulse filamentation and supercontinuum generation in water
and fused silica was performed. For interpretation of experimental and numerical results we
proposed a simple interference model according to which the CE frequency-angular spectrum is the
result of the interference of broadband radiation from moving point sources in the filament. The
model reproduces the formation of the X-, O-, and Fish-shaped spectrum, which is typical for the
pulse filamentation in conditions of normal, anomalous, and zero group-velocity dispersion. We
discovered the appearance of fine structure in the conical emission spectrum produced by lengthy
filament. We established general laws of conical emission formation based on the concept of white
light generation and interference from the moving point sources produced by the filament. It is
shown that the conical emission frequency-angular spectrum is produced by interference of
coherent radiation from one or several moving point sources in the lengthy filament. The shape of
the conical emission spectrum depends on the medium material dispersion, the spectrum structure is
determined by length and relative location of filament emitting regions. Analytical expressions for
frequency-angular distribution of the spectral intensity I(θ,λ) for pulses with various wavelengths
and different regimes of filamentation were obtained. These expressions describe the fine structure
of the CE angular spectrum in lengthy filament and the splitting of the CE rings after refocusing in
concordance with experiments.
This work was supported by the Russian Foundation for Basic Research (Grant No. 08-0200517-a) and by the Russian Federal Agency for Science and Innovation (Rosnauka, the state
contract 02.740.11.0223).
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 9:
Ultrafast laser micro/nano processing of high aspect ratio channels in
dielectrics with Bessel beams
M.K. Bhuyan, F. Courvoisier*, M. Jacquot, P.A. Lacourt, L. Furfaro and John M. Dudley
FEMTO-ST Institute, Department of Optics P.M. Duffieux, UMR CNRS 6174,
Université de Franche-Comté, 25030 Besançon, France
* Tel: (+33)3 81 66 64 01, Fax: (+33)3 81 66 64 23, e-mail: [email protected]
Abstract: Femtosecond laser machining is a powerful technique for processing dielectrics down to subwavelength scales. However,
controlling in-depth energy deposition is challenging due to nonlinear processes occurring at high intensities. We show that
femtosecond Bessel beams allow for a precise control on this parameter and for fabricating high aspect ratio micro and nanochannels. The underlying physical mechanisms will be discussed.
Femtosecond laser machining of transparent materials has been applied to a wide range of applications, from waveguide
fabrication to the writing of micron and nanometer scale surface and bulk features through material ablation [1].
Femtosecond machining is particularly attractive because of its low cost and its ability to rapidly machine complex
geometrical structures in two and three dimensions. Specifically, sub-10 µm channels are essential structures in the
development of system-scale lab-on-chip and sub-micron channels are key components for photonic devices and
nanofluidic systems. A particular challenge in femtosecond machining therefore concerns the fabrication of such high
aspect ratio channels because strong focusing of Gaussian beams typically limits the longitudinal machining region to
only 1 µm [2].
Figure 1 Bessel beam position in the sample (top left) and image of a microchannel processed with
1000 shots(bottom left). A schematic representation of the energy flow in the Bessel beam
producing the plasma channel is shown on the right side.
In this presentation, we will review our recent work using nondiffracting Bessel beams to overcome many of the
difficulties of Gaussian beam femtosecond laser micromachining. Our results show that Bessel beams can be used to
generate taper-free channels of around ~2 µm diameter and ~80 µm length in glass in a straightforward setup without
the need for any sample translation. We interpret these results in terms of a specific regime of stable filament formation
[4], and identify a working window for the practical use of Bessel beams for glass micromachining. Recent results
concerning high aspect ratio nanochannels processing will also be presented with important applications to photonic
devices fabrication.
References
[1] Gattass, R.R.; Mazur, E. Nat Photonics, 2, 219-225 (2008)
[2] Kudryashov, S.I.; Mourou, G.; Joglekar, A.; Herbstman, J.F.; Hunt, A.J. Appl. Phys. Lett. 91, 141111. (2007)
[3] Courvoisier, F. et al.. Opt. Lett. 34, 3163-3165 (2009).
[4] Bhuyan, M.K. et al. Opt. Express 18, 566-574 (2010)
Page 20
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 10: Single process femtosecond laser microfabrication — novel technology in modern photonics: meticulous experiments and serious numerics
Vladimir Mezentsev
Photonics Research Group
Aston University
Birmingham B4 7ET
United Kingdom
Recent results are presented on femtosecond (fs) laser microfabrication of key components for integrated
optics such as highly curved low-loss waveguides in glasses, depressed cladding waveguides in crystals.
Details of microfabrication and characterisation are discussed. Full vectorial Maxwell's simulations are
required to get quantitative description of femtosecond electromagnetics of tightly focussed laser beam. First
results on such modelling are presented and discussed.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 11: Femtosecond ablation of dielectrics: time resolved studies of excitation
mechanisms
Stéphane Guizard1*, Nikita Fedorov1, Alexandros Mouskeftaras1, Sergey Klimentov2,
1
Laboratoire des Solides Irradiés, Ecole Polytechnique, 91128 Palaiseau, France.
2
General Physics Institute of the Russian Academy of Sciences, Vavilova St 38, 11991 Moscow,
Russia.
*e-mail: [email protected]
Abstract : In the field of laser ablation of wide band gap materials by ultrashort laser pulses, there
has been a long debate regarding the excitation and energy deposition mechanism. This is due to the
lack of direct experimental investigations, which have been mostly limited to the measurement of
ablation threshold. Indeed, the measurement of this single parameter, besides its technological
importance, is clearly insufficient to understand a phenomenon as complex as laser induced
breakdown. The complexity arises from the intricate evolution of the laser pulse propagation and
the optical properties of the solid, due to the onset of a dense electronic excitation. If we consider
only the very first step which is the electronic excitation, it is noteworthy to observe that one can
still find advocate of different mechanisms such as tunnel [1], avalanche [2], or multiphoton [3]
ionisation.
To investigate this problem, we use an original pump-probe interferometry technique [4, 5] which
allows to measure the carrier density as a function of time, and to observe the initial relaxation
mechanisms. We will show that, using a pair of excitation pulses with well chosen characteristics, it
is possible to clearly identify the excitation mechanism at work at intensities when the breakdown
threshold is reached. By using this approach on Al2O3 samples, we have obtained original results
showing that the breakdown mechanisms is not involving an increase of the density of carrier, as
expected from the avalanche model, but rather from an efficient energy deposition mechanism, by
linear and non linear absorption of photons by the previously excited carriers.
[1] I. N. Zavestovskaya, P. G. Eliseev, O. N. Krokhin, N. A. Men’kova, Apll. Phys. A, 2008, 92,
903.
[2] L. Englert, B. Rethfeld, L. Haag, M. Wollenhaupt, C. Sarpe-Tudoran and T. Baumert, Optics
Exp. 15, 17855, 2007.
[3] V. Temnov, K. Sokolowski-Tinten, P. Zhou, A. El-Khamhawy, and D. Von Der Linde, Phys.
Rev. Lett. 97, 2006, 237403.
[4] Audebert P., Daguzan Ph., Guizard S., et al. Physical Review Letters 52, p. 1994.
[5] Martin Ph., Guizard S., Daguzan Ph., Petite G., D'Oliveira P., Meynadier P. Perdrix M., Phys.
Rev. B, 55, 5799, 1997.
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 12: Ultra-short laser interactions: insights from numerical modeling
N. S. Shcheblanov1, M. E. Povarnitsyn2, Th. Derrien3, and T. E. Itina1
1Laboratoire Hubert Curien (LaHC), CNRS/Université Jeann Monnet, Bat. F , 18 rue du Professeur
Benoît Lauras, Saint Etienne, 42000, France
2Joint
Institute for High Temperatures RAS, 13 Bd. 2, Izhorskaya street, Moscow, Russia
3Laboratoire
Lasers, Plasmas et Procédés Photonique (LP3) CNRS/Université de la Méditerranée,
Case 917, 163 avenue de Luminy, 13288 Marseille, France
Better understanding of ultra-short laser interactions requires two-temperature modeling of
laser energy absorption and its following relaxation. In particular, two-temperature hydrodynamic
model with a thermodynamically complete equation of state provide insights into the ablation
mechanisms are observed. For metal targets, the major fraction of the ablated material is found to
originate from the metastable liquid region, which is decomposed either thermally or mechanically.
In addition, effects of the ultra-short laser excitations on semiconductors and wide band gap
materials require particular attention.
In this case, material ionization through multi-photon
excitation and electron-impact ionization should be considered. These processes are modeled by
using a detailed kinetic approach.
Laser-irradiated material response is based on the electron-phonon/ion interactions, which
in turn depend strongly on the energy of the electron sub-system defined by laser parameters and
on the material properties. In this study, based the numerical modeling, we propose the energybased analysis of these interactions.
Single, double and multiple shot interactions are simulated with a particular focus on the
control over the transient reflectivity changes and the energy deposition rate. We show that the
history of laser excitations affects not only the ionization process and the final number of the
conduction band electrons, but also determines the rate of the energy deposition into the material.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 13: Explosive Evaporation of Large Water Droplet Irradiated by Ultrashort
Laser Pulses
Yu.E. Geints1, S.S. Golik2, A.M. Kabanov1, V.K. Oshlakov1, and A.A. Zemlyanov1
1
Zuev Institute of Atmospheric Optics SB RAS, Tomsk, Russia
Yu.E.Geints e-mail: [email protected]
2
Far Eastern State University, Vladivostok, Russia
Abstract
We have investigated for the first time experimentally and theoretically the interaction of
high-intensive femtosecond laser pulses (800 nm, 1 mJ, 50÷800 fs@1 kHz) with large isolated
suspended in air millimetric drops made of distilled water. The experiments have shown that upon
ultrashort light irradiation large optically transparent drops can evaporate and boil-up with bubble
formation and hot steam/liquid fragments release. This boiling-up dynamics demonstrates an
explosive character and in the condition of long-term laser illumination the boiling channel covers
the major part of the droplet diameter. The theoretical analysis shows that the most probable
physical mechanism of drop explosive evaporation is plasma formation due to laser-induced
breakdown (LIB) inside a droplet in areas of laser internal intensity maxima (the “hot spots”).
These spatial zones, in turn, are supported by the focusing effect of spherical air-droplet interface.
The thermalization of dense plasma produced by multiphoton/avalanche ionization of water
molecules in “hot spots” can lead to the significant rise in water temperature (> 1000 K) and
pressure (> 10 kbar) and cause droplet fragmentation.
The explosive evaporation of large water droplet irradiated by a train of 800-nm
femtosecond laser pulses is accompanied by a bright near isotropic droplet emission in the visible.
The brightness of this emission source and its spectral composition also strongly depend on the
initial laser power. At the high intensity of irradiation the emission lines of oxygen and hydrogen
ions produced by LIB of water are clearly distinguishable in the spectrum. Moreover, integrally the
emission spectrum broadens with the increase in laser pulse power. The temporal dynamics and
spectral form of this emission can be attributed to the combined effect of pulse self-phase
modulation in water due to Kerr and plasma optical nonlinearity and blackbody-type emission of
heated liquid with the temperature of approximately thousands absolute degree.
Page 24
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 14:
Short pulses approximation in dispersive media
David Lannes
Département de Mathématiques et Applications
Ecole Normale Supérieure
45, rue d’Ulm
75005 Paris
FRANCE
We derive various approximations for the solutions of nonlinear hyperbolic systems with fastly oscillating
initial data. We first provide error estimates for the so-called slowly varying envelope, full dispersion, and
Schrodinger approximations in a Wiener algebra; this functional framework allows us to give precise
conditions on the validity of these models; we give in particular a rigorous proof of the “practical rule”
which serves as a criterion for the use of the slowly varying envelope approximation (SVEA). We also
discuss the extension of these models to short pulses and more generally to large spectrum waves, such as
chirped pulses. We then derive and justify rigorously a modified Schrödinger equation with improved
frequency dispersion. Numerical computations are then presented, which confirm the theoretical predictions.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 15:
A nonlinear quantum optics model for laser-gas
interaction in some extreme regimes
E. Lorin1,3,_, S. Chelkowski2, and A. Bandrauk2,3
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 16:
High Frequency Behaviour of the Maxwell-Bloch
Model with Relaxations: Convergence to the SchrödingerBoltzmann System
F. CASTELLA (1) AND E. DUMAS (2)
WLMI-2010
Page 27
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 17:
On three-wave coupling system and the related
simulations of the Brillouin Backscattering for ICF target.
Remi Sentis
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 18:
Plasma expansion into a vacuum and ion acceleration
P. Mora
Centre de Physique Théorique, Ecole Polytechnique, CNRS, 91128 Palaiseau, France
Laser created plasma expansion into a vacuum leads to energetic ions which present a
strong interest for various applications such as hadron (proton) therapy, proton imaging, nuclear
physics, ion accelerators, fast ignition, warm dense matter production, etc. In the case of ultra-high
intensity lasers interacting with thin foils, the laser energy is absorbed by suprathermal electrons
which acquire relativistic energies. These electrons invade the foil and cause its expansion, by
progressively transferring their energy to the ions. Similarly thin foils heated by various means
(electrons, protons, X-rays) expands into vacuum. We will present various results concerning
plasma expansion into a vacuum, involving purely kinetic effects, collisional effects,
electromagnetic instabilities, multi-species ions, two temperatures electron distribution function,
etc.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 19: Towards improving the quality of laser-produced particle sources
V. Yu. Bychenkov
P. N. Lebedev Physics Institute, Russian Academy of Science, Leninskii Prospect 53,
Moscow 119991, Russia
A long-term difficulty — generation of the very broad, thermal-like energy spectrum of the
accelerated particles from short laser pulse interaction with plasma has been overcome recently for
both electron and ion beams. This step towards monoenergetic particles shows a distinct
improvement of energy spectra, opening new possibilities for different applications. Here we report
recent progress in the above aspect achieved by Lebedev Physics Institute with theory of laser
triggered particle acceleration and multidimensional PIC simulations. Both simulation-theoretical
studies and simulation models for interpretation of the recent experimental results will be presented.
Several models and schemes for production of electrons and ions with monoenergetic
features are discussed.
(a) The collisionless adiabatic expansion into vacuum of spherical and plane plasma targets
composed of two-species ions and hot electrons is studied kinetically by theoretically and numerical
solving of the equations of motion of plasma particles in the self-consisting electrostatic field.
Special attention is paid to optimization of light ions acceleration from two ion species
heterogeneous (structured) and homogeneous targets. (b) The performed 3D PIC simulation study
demonstrates that protons beam with therapeutic energy and small energy spread can be generated
from ultra-thin (with thickness of tens nanometers) mass-limited targets with hydrogenised impurity
irradiated by powerful (with intensity of the order of 1022 W/cm2) ultra-short laser pulses.
(c) Simulations with a hybrid code that combines kinetic PIC model with field ionization input
demonstrate that collimated beams of backward electrons with quasi-monoenergetic feature can be
produced by tightly focused millijoule-energy femtosecond laser pulses incident onto a soliddensity plasma with about micron scale length. These simulations are in good agreement with the
experimental results on production of electron beams from the interaction of relativistically-intense
laser pulses with a solid-density SiO2 target.
(d) The hybrid code was also used for study of high-energy electron production in a laser wakefield
accelerator in a bubble regime. This study indicates enhanced electron trapping initiated by field
ionization of target ions. In agreement with experiment, the addition of a higher Z additive has been
shown to increase the trapped charge and lower the transverse emittance of the generated electron
beam as compared to pure gas at the same electron density.
(e) We have demonstrated that dense hydrogen gas jet or hydric aerogels may serve as competitive
sources of protons with therapeutic energy and small energy spread. The space-temporal and
spectral features of the protons accelerated from such low-dense targets are compared with that
from the thin foils.
This work was partly supported by the Russian Foundation for Basic Research.
Page 30
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 20: Laser-based ion acceleration: new progress and perspectives for
application
S. Ter-Avetisyan1, R. Prasad1, D. Doria1, K.E. Quinn1, L. Romagnani1, P. Gallegos2, 3,
P.S. Foster1,2, C.M. Brenner2,3, J.S. Green2, M.J.V. Streeter2, D.C. Carroll3, O. Tresca3,
N. Dover4, C.A.J. Palmer4, J. Schreiber4, D. Neely2, 3, Z. Najmudin4, P. McKenna3,
M. Zepf1, and M. Borghesi1
1
School of Mathematics and Physics, Queen's University Belfast, Belfast, UK
2
CLF, Rutherford Appleton Laboratory, STFC, Oxfordshire, UK
3
SUPA Department of Physics, University of Strathclyde, Glasgow, UK
4
The Blackett Laboratory, Imperial College, London, UK
Recent advances in laser technology have led to laser systems with high contrast and extreme intensity values, which
have opened up new perspectives in the field of laser–matter interactions. We will discuss recent results obtained in the
high power (300 TW) Astra-GEMINI laser system at the Rutherford Appleton Laboratory (RAL). These development
enabled access to unprecedented intensities (above 1020 W/cm2), an order of magnitude higher than the previously
achieved with ultra-short (~ 50 fs) laser pulses. The interaction of such an intense and high contrast (~ 1010) laser pulses
with matter still has to be explored carefully and the experiments aiming to obtain scaling laws or conversion
efficiencies are essential.
The measurements provided for the first time the opportunity to extend scaling laws for the acceleration process in
the ultra-short regime beyond the 1020 W/cm2 threshold, and to access new ion acceleration regimes. Comprehensive
on-line diagnostics with high resolution led to a full characterization of the ion emission process and accelerated beam
characteristics. The scaling of accelerated proton energies was investigated by varying a number of parameters such as
target thickness (down to 10 nm), target material (C, Al), laser light polarization (circular and linear) and angle of laser
incidence (oblique - 350, and normal). A pronounced increase in the ion energies has been observed for ultra-thin targets
(10 - 100 nm) at normal laser incidence, with peak energies (~ 20 MeV for protons, ~ 240 MeV for C) significantly
higher than previously reported with ultrashort laser pulses. The transition to a “new” regime of ion acceleration, the socalled Radiation Pressure Acceleration (RPA) regime, was also identified, showing quasi-monoenergetic proton spectra
and a more favorable ion energy scaling with laser intensity. The experiment was carried out in the framework of the
LIBRA project.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 21:
Laser ion acceleration in shaped mass-limited targets
A.A.Andreev1,2
1. Max-Born Institute, Berlin, Germany
2. SIC “S. I. Vavilov State Optical Institute”, St. Petersburg, Russia
Ultrahigh intensity (UHI) laser radiation produces fast ions at interaction with solid targets. Most
groups use in experiments a thin foils because of the possibility to characterize them well and they
can be positioned easily. UHI laser pulses may accelerate ions in thin foils to energies of several
MeV per nucleon and highly collimated ion beams may be formed. In order to avoid the slowly
moved foil regions it has been proposed to use a small target with radius about laser spot size, so
named mass limited target (MLT). Because these MLT are near solid density and with sizes that are
comparable to the laser spot size, high laser pulse absorption and strong laser plasma interaction are
expected, where the absorbed energy does not lose to its surroundings through rapid conduction
processes. Ion acceleration in targets irradiated by UHI laser pulses has been studied here with
analytical model and PIC simulations. Simulations were performed for different sizes and shape
targets. Energy spectra of fast ions, laser conversion efficiency to fast ions and the divergence of ion
beams are compared for various types of targets. When MLT is irradiated by UHI laser pulse, the
resulting pellet plasma is strongly accelerated forward. Even after the laser pulse is reflected, the
remaining high-intensity region continues to accelerate forward within the rapidly moving plasma
bunch. The kinetic energy of the ions in the bunch’s densest region can exceed tens MeV at about
solid density. It was shown that a diffracted laser light additionally accelerates electrons at MLT
rear and produces short electron bunches, which correlates with light structure. If the laser spot size
is bigger than MLT the radial force at vacuum MLT boundary can provide confinement. The regime
of a most effective acceleration is realized in the case when laser field is about electrostatic field of
ion core of MLT. It is found that maximal energy of ions and its directionality can be significantly
enhanced, by choosing of shaped targets. The results of the simulations were compared with the
experimental data and have shown a good coexistence.
Page 32
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 22: Recent results on unstable relativistic electron transport into dense
plasmas
Laurent Gremillet, Benoît Vermersch, Didier Bénisti, Erik Lefebvre
CEA, DAM, DIF, 91297 Arpajon, France
Understanding the transport of electron beams in dense plasmas is of critical importance in many
physical settings, notably in the context of relativistic laser-plasma interaction. We will report on
recent results on this topic with particular emphasis on the collective effects arising from beamplasma instabilities [1].
The first part of our presentation will address the issue of collisional effects on the purely
electrostatic beam-plasma instability. This is a long-standing issue [2] here revisited within the
rigorous framework of the Vlasov-Landau equation. Exact numerical results will be presented as
well as analytical estimates of the maximum growth rate as a function of the system parameters.
The conditions for collisional stabilization will be highlighted, and compared to those obtained
from simplified Krook-like models.
The second part will focus on the space-time dynamics of the unstable transport of laser-driven
electrons by means of particle-in-cell simulations. Within a 1-D geometry, it will be demonstrated
that, although the longitudinal momentum distribution of the fast electrons at the target boundary
may be a quasi-stationary decreasing function of the longitudinal momentum, time-of-flight effects
lead to a time-varying bump-on-tail distribution deep into the target prone to electrostatic beamplasma instabilities, a process reminiscent of that extensively investigated in the context of type III
solar radio bursts [3,4]. For commonly considered laser-plasma parameters, the quasilinear
relaxation proves to be fast enough to generate a plateau within a broad region of the hot electron
phase-space. The dynamics of the plateau formation will be investigated in connection with the
excitation of the plasma waves at the beam front, and their subsequent reabsorption by slower
electrons. A self-similar analytical model extending that of Zaitsev et al. [3] will be presented and
compared to the simulations. The consequences of this transient quasilinear relaxation on the hot
electron energy transport will be discussed, as will be the extension of these results to mobile ions
and to a 2-D geometry.
[1] A. Bret, L. Gremillet, D. Bénisti and E. Lefebvre, Phys. Rev. Lett. 100, 205008 (2008).
[2] H. E. Singhaus, Phys. Fluids 7, 1534 (1964).
[3] V. V. Zaitsev et al., Sov. Phys. JETP 18, 147 (1974).
[4] G. R. Foroutan et al., Phys. Plasmas 12, 042905 (2005).
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 23:
Single and multiple filamentary self-compression scenarios
Günter Steinmeyer1,2, Carsten Brée1,3, Ayhan Demircan3, Stefan Skupin4, Luc Bergé5
1
Max-Born-Institut (MBI), Max-Born-Straße 2a, 12489 Berlin, Germany e -mail: [email protected]
2
Optoelectronics Research Centre (ORC), Tampere University of Technology, 33101 Tampere, Finland
Weierstraß-Institut für Angewandte Analysis und Stochastik (WIAS), Mohrenstraße 39, 10117 Berlin, Germany,
4
Max-Planck-Institut für Physik komplexer Systeme (MPIPKS), Nöthnitzer Straße 38, 01187 Dresden, Germany
5
CEA-DAM, DIF, F-91297 Arpajon, France
3
The combined action of plasma nonlinearity, Kerr nonlinearity, and linear optical effects in a
filament can serve to compress mJ laser pulses without any need for external dispersion
compensation. Self-compression of 40 fs input pulses has been demonstrated in several laboratories
to date, resulting in sub-10 fs output pulses. Numerical simulations [1] have helped in clarifying the
underlying mechanisms, which chiefly act in the spatial domain, contrasting other laser pulse
compression schemes, in which dispersion and Kerr nonlinearity act together for temporal pulse
contraction. Self-compression typically goes through 3 characteristic stages [2]: In a first stage, the
beam profile contracts in its leading and trailing edges and expands around the input pulse peak.
Eventually, this causes the on-axis temporal profile to split, yielding a pulse shape with two distinct
maxima. Subsequently, one of these pulses starts to diffract out into the reservoir, yielding again a
single-maximum pulse shape. This split-isolation cycle alone typically provides about threefold
compression. The isolated pulse may then undergo further shortening due to nonlinear propagation.
Fig. 1: Single and double self-compression (a) Temporal pulse profile evolution in the single-compression regime. (b) Same in the double
compression regime. Inset shows zoomed view of the second split event. (c) Evolution of peak intensity during propagation for single (dashed)
and double (solid) compression. Inset shows resulting temporal profiles. (d) Evolution of pulse duration during propagation.
In this contribution, we will show that self-compression can be cascaded in a single gas cell,
without the need for intermediate dispersion compensation or recompression, see Fig. 2(b). The
cascaded self-compression gives rise to characteristic spatio-spectral energy distributions that can
be seen in numerical simulations as well as in experiments. The latter clearly revealed two separated
ionized zones. We will further elucidate the appearance of negative distributions to the group delay
dispersion from nonlinear optical effects, another characteristic feature frequently observed in selfcompression experiments. We believe that this dispersion contributions stem from nonlinear effects
inside the windows of the gas cell, similar to those first discussed in [3]. We will provide
experimental evidence for an important role of the windows for pulse shaping in self-compression.
Additionally, we will discuss some novel ideas for theoretically explaining this effect. Both these
results, the double self-compression as well as the dispersion contribution of the windows, widen
the scope of applicability of self-compression schemes and add to a deeper understanding of this
remarkable laser pulse compression mechanism.
[1] S. Skupin, G. Stibenz, L. Bergé, F. Lederer, T. Sokollik, M. Schnürer, N. Zhavoronkov, G. Steinmeyer, Phys. Rev.
E 74, 056604 (2006).
[2] C. Brée, A. Demircan, S. Skupin, L. Bergé, G. Steinmeyer., Opt. Express 17, 16429 (2009).
[3] L. Bergé, S. Skupin, G. Steinmeyer., Phys. Rev. Lett. 101, 213901 (2008).
Page 34
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 24:
Ionization induced post compression of high energy pulses
A. Dubrouil, C. Fourcade Dutin, S. Petit, E. Mével, D. Descamps and E. Constant
Centre Lasers Intenses et Applications (Université de Bordeaux, CNRS, CEA, UMR5107),
Université Bordeaux1, France ; www.celia.u-bordeaux1.fr
[email protected]
High energy ultrashort pulses are a key tools for studying or initiating ultrafast processes.
Amplification of very short pulses to achieve high energies leads however to spectral narrowing that pushes
their duration above the minimum value imposed by the gain bandwidth. To overcome these limitations,
post-compression techniques have been developed to obtain broadband ultrashort pulses that can even be
shorter than the minimum pulse duration imposed by the gain media. These techniques require to create
new frequencies by a non linear process and rephase all the frequencies to get shorter pulses. Usually the
non linear steps is based on self phase modulation (SPM) that can significantly broaden the pulse spectrum.
To achieve a uniform beam, SPM can occur in a guided geometry either by using a capillary filled with gas
[1] or by using a self guided geometry where the interplay between Kerr effect and ionization leads to selfguiding [2]. In both cases, the gas pressure is usually high and several parameters such as self-focusing and
ionization limit the output peak power [3] and thereby the energy of the post compressed pulse to the mJ
level [4].
We present here a new optical post-compression scheme [5] where we use Helium ionization as
the spectral broadening mechanism. This is suitable for recompression and compatible with using a gas
pressure that is low enough not to perturb beam propagation. To ensure spatial beam homogeneity, the
beam propagates in hollow capillary filled with few mbar of helium gas designed for high energy ultra-short
pulses. The blue-shifted pulses are then compressed with a combination of chirped mirrors and silica plates.
We could obtain a significant spectral broadening associated with a chirp that could be compensated. From
a conventional Ti:sapphire laser chain providing pulses of 40 fs – 70 mJ, we demonstrate pulses with a total
output energy of 13.7mJ (Fig.1) and a duration of 11.4 fs and nice spatial properties.
The pulses were characterized both with single shot autocorrelator and with a single shot SHG frequency
resolved optical gating (FROG) [6].
20
15
10
10
5
5
0
1
2
3
4
5
6
7
8
Helium pressure (mbar)
Fig. 1. Output energy and duration
of the post compressed pulse for
several helium pressures.
9
0
1,2
1,5
2
Experimental spectrum
Retrieved FROG spectrum
Phase
FT experimental spectrum
Retrieved FROG profile
Temporal phase
(a)
0
1,0
0,8
0,6
-2
Intensity (u.a.)
15
Intensity (u.a.)
Best values 25
1,4
(b)
4
FWHM 11.4 fs
1,0
2
0,5
Phase (rad)
20
FWHM of pulse duration (fs)
35
30
0
1,6
40
Pulse duration
Transmitted energy
25
Phase (rad.)
Output energy (mJ)
30
0,4
0
0,2
0,0
600
650
700
750
800
Wavelength (nm)
850
-4
900
0,0
-40
-30
-20
-10
0
10
20
30
40
Time (fs)
Fig. 2. SH FROG measurement of our shortest pulses : in (a) experimental and
retrieved FROG spectra of the post-compressed pulse with the residual spectral
phase, in (b) intensity profile and temporal phase of the post-compressed pulses.
The temporal phase of the shortest pulse exhibits a constant value over a large part of the pulse leading to
an excellent recompression (figure 2) and the 11.4 fs FWHM duration of the post-compressed pulse is close to the
inverse Fourier Transform FWHM of the experimental spectrum (10.4 fs). This new technique is therefore compatible
with the post compression of high energy short pulses and allowed us to reach the 10 mJ – 10 fs level. This is very
promising to generate high energy isolated attosecond pulses [7] suitable for XUV induced pump-probe experiments
with as resolution.
1. M. Nisoli, S. De Silvestri and O. Svelto , Appl. Phys. Lett. 68, 2793 (1996).
2. C. Hauri, W. Kornelis, F. Helbing, A. Henrich, A. Couairon, A. Mysyrowicz, J. Biegert, U. Keller, Appl. Phys. B 79, 673
(2004).
3. M. Nurhuda, A. Suda, K. Midorikawa and K. Nagasaka, J. Opt. Soc. Am. B 20, 2002 (2003).
4. S. Bohman, A. Suda, T. Kanai, S. Yamaguchi and K. Midorikawa, Opt. Lett. 35, 1887 (2010).
5. C. Fourcade-dutin, A. Dubrouil, S. Petit, E. Mével, E. Constant and D. Descamps, Opt. Lett. 35, 253 (2010).
6. R. Trebino and D. J. Kane, J. Opt. Soc. Am. B 11, 2206 (1994).
7. V. V. Strelkov, E. Mével and E. Constant, New J. Phys. 10, 083040 (2008).
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 25: Few-cycle energetic femtosecond pulses in the visible and near-IR by
using cascaded quadratic soliton compression
Page 36
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 26: Pulse propagation effects in high order harmonic generation by midinfrared source
V. Tosa1, K. Kovacs1, C. Vozzi2, M. Negro2, F. Calegari2, and S. Stagira2
1
Natl. Institute for R&D Isotopic and Molecular Technologies, Cluj-Napoca, Romania
2
Dipartimento di Fisica & CNR-IFN, Politecnico di Milano, Milano, Italy
On-axis intensity (1014 W/cm2)
The limited photon energy and photon flux currently available is a major drawback of high order
harmonic generation (HHG). A recently investigated route to higher photon energy is HHG driven
at wavelengths l longer than the 800 nm of the Ti:Sa laser. At constant intensity, longer
wavelengths generate more energetic electrons, opening the possibility of producing multi-kilovolt
photons of coherent radiation.
Macroscopic aspects of HHG cannot be disregarded in any experiment aiming to optimize the HHG
yield. Propagation effects, seen as modifications in the spatial, temporal/spectral structure of the
laser pulse are stronger for longer wavelengths because the refractive index change is more
sensitive to the plasma variation.
In this work we analyze the laser field configuration established as a result of 1550 nm wavelength
20 fs pulse propagation in a Xe jet. We calculated the field amplitude and phase of the field using a
non-adiabatic three-dimensional model in a focusing geometry of cylindrical symmetry.
The figure illustrates the on-axis intensity
for several runs. For each run a gas
4.5
medium 1.5 mm long at 20 Torr pressure
4.0
was placed at different relative positions
Initial field
Propagated field
of the jet with respect to the focus. One
3.5
can observe that for most of the runs, the
3.0
on-axis propagated field levels-off at an
intensity of ~1.5×1014 W/cm2, regardless
2.5
the initial intensity.
This pattern
2.0
maintains also for different gas pressures,
the higher the pressure the lower the
1.5
established on-axis intensity.
1.0
The propagated laser field was used to
calculate single dipole response in the
z (mm)
strong field approximation and finally to
integrate the Maxwell equation for the
harmonic field. The results were found in good agreement with experimental spectra measured
recently and were used further to reveal the HHG physics behind the data. We will show how the
propagation of the mid-infrared pulse in an ionizing medium directly influences the HHG. We will
demonstrate that for these driving frequencies even very low ionization levels perturb the laser
pulse propagation and determine the way in which HHG process takes place.
0.5
-8
-6
-4
-2
0
2
4
6
8
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 27:
Parametric wave mixing in nonlinear disordered media
Wieslaw Krolikowski
Laser Physics Centre, Research School of Physical Sciences and Engineering, Australian National
University, Canberra, Australia
Email: [email protected]
There is a natural common perception that coherent optical phenomena are always
intimately associated with the ordered perfect medium. This is for instance the case of normal light
propagation in crystals where particular ordering of atoms or ions and associated with this ordering
spatial symmetry defines particular optical properties including the nonlinear optical response. In
fact the lack of this ordering immediately precludes certain optical properties from being observed.
Therefore one can intuitively expect the strong sensitivity to the medium ordering in case of
nonlinear properties of the medium. However it turns out that this is no always true and actually
introducing disorder into otherwise perfect optical system (structure) is in fact beneficial. It turns
out that random ferroelectric domain structures formed naturally in ferroelectric crystals which
exhibit multi-domain structure with domains having random distribution of size and orientation can
be useful in realization of various parametric processes. Such a disordered nonlinear medium is
equivalent to an effective QPM system with almost infinite set of reciprocal wave vectors enabling
to quasi-phase-match any parametric process, e.g. second harmonic generation or sum-frequency
mixing, in a ultra-broad frequency range.
In this talk we present our recent experimental and theoretical results on second and third
harmonic generation in such random nonlinear structures formed in as-grown strontium barium
niobate crystals as well fabricated structures in lithium niobate. We will consider various types of
interaction geometry, discuss spatial and polarizational properties of the emitted harmonic waves
and the possible application of this process.
Page 38
WLMI-2010
WORKSHOP ON LASER-MATTER INTERACTION 2010
O 28:
Nonlinear photonics in silicon nano-structures
A.V. Gorbach
Centre for Photonics and Photonic Materials, Department of Physics,
University of Bath, Bath BA27AY, UK
Recent progress in the fabrication of nano-structures has stimulated active research in
sub-wavelength light guidance and manipulation. Silicon-on-insulator waveguides [1]
appear to be promising candidates to become basic elements in nano-photonics. The
large refractive index of silicon (n~3.5 at telecom wavelength) allows for tight light
confinement by the conventional total internal reflection mechanism, giving the
simultaneous advantages of controlled dispersion, and manageable losses. Bringing two
silicon waveguides together with a separation of few tens of nanometres produces a high
intensity peak in the slot area between the waveguides, with the field predominantly
polarized perpendicular to the slot interface [2]. Combination of light being tightly focused
in a nanometre scale area, and strong ultrafast Kerr nonlinearity of silicon and/or of
dielectrics and polymers filling the slot, makes silicon waveguides and their arrangements
to be perfect testing ground for various nonlinear effects. Crucially, main approximations of
the conventional and well-established scalar Schrödinger-type models are invalidated due
to the abrupt and strong variations of both linear and nonlinear material properties on the
sub-wavelength scale. Thus one needs to develop adequate theoretical tools.
In this talk I will overview our recent theoretical and experimental research of nonlinear
effects in silicon nano-structures. Starting from first principles, we developed the set of
theoretical and computational tools to analyze nonlinear guided modes in silicon slot
waveguides and their arrays, as well as basic nonlinear effects in these setups, such as
frequency mixing, modulational instability, resonant radiation by solitonic modes.
References:
[1] For a recent review see e.g. R. M. Osgood et al., Adv. Opt. Photon. 1, 162 (2009).
[2] C. Koos et al., Nature Photonics 3, 216 (2009).
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 29: Generation of high-power supercontinuum and tunable sub-10-fs VUV
pulses in photonic crystal fibers
J.Herrmann, S.-J. Im and A. Husakou
Max Born Institute, Berlin, Germany
Phone: +493063921278, Fax: +493063921209, e-mail: [email protected]
A decade ago, the discovery of soliton-induced supercontinuum generation in photonic
crystal fibers (PCFs) [1,2] has led to extensive research and numerous fascinating
applications in frequency metrology, coherence tomography, absorption spectroscopy and
other fields. Despite the progress in this field, the output peak powers of supercontinua
were up to now limited by the low radius and low damage threshold of solid-core PCFs. In
the present talk we study kagome-lattice hollow-core PCFs [3] as an alternative and
predict the generation of high-energy soliton-induced supercontinua with spectral width of
more than two octaves. Besides, we predict the generation of isolated UV/VUV 5-fs pulses
without external chirp compensation during this spectral broadening process, tunable from
350 nm to 120 nm by the variation of pressure. Finally we present results on
supercontinuum generation in a water-filled PCF.
We have simulated the pulse propagation using the Forward Maxwell equation [2] which
includes group velocity dispersion to all orders, as well as the Kerr nonlinearity, plasma
effects, and higher-order nonlinear effects. The evolution of the output spectrum is
presented in Fig. 1(a) for a 50-fs, 100-TW/cm2 input pulse at 800 nm with output energy of
0.07 mJ, which exceeds the results obtained in solid-core PCFs by roughly five orders of
magnitude. As can be seen the spectrum contains a bright spectral peak at around 200 nm
which corresponds to an isolated VUV pulse with 5 fs duration [Fig. 1(b)]. The spectral
position of the pulse can be easily tuned by changing the pressure.
Finally, supercontinuum generation in a water-filled PCF is studied. By filling the central
hollow core of this fiber with water, bandgaps do not arise and broadband guiding is
posible. Using a pump at 1200 nm and few-microjoule pump pulses, the generation of
high-coherent supercontinua with two-octave spectral coverage from 410 to 1640 m is
predicted. Our simulations indicate a transition from the soliton-induced mechanism to selfphase modulation dominated spectral broadening with increasing pump power. The
numerical simulations show good agreement with experimental measurements at the Max
Born Institute.
(a)
Fig.1 Evolution of spectrum (a) and output spectrum for different pressures (b). In (b) the pressure is 2 atm
(red), 1 atm (green) 0.5 atm (blue) and 0.25 atm (black).
References
1. J. K. Ranka, R. S. Windeler, and A. J. Stentz, Opt. Lett. 25, 25 (2000).
2. A. Husakou and J. Herrmann, Phys. Rev. Lett. 87, 203901 (2001).
3. F. Couny et al., Science 318, 1118 (2007).
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 30: Observation of extreme temporal events in CW-pumped supercontinuum
M. Taki, A. Mussot, A. Kudlinski, M. Kolobov, E. Louvergneaux
Université Lille 1, Laboratoire PhLAM, IRCICA, 59655 Villeneuve d’Ascq Cedex, France
*[email protected]
Abstract: We study experimentally and numerically the temporal features of
supercontinuum generated with a continuous-wave ytterbium-doped fiber laser.
We show that the temporal output of the supercontinuum is characterized by
strong and brief power fluctuations, i.e. so-called optical rogue waves. We
show that, in the linear regime, modulational instability is one of crucial
mechanisms in their formation. We also show how the power of extreme events
is further enhanced by higher order dispersion impacting their probability
density function. In the nonlinear regime, we demonstrate numerically that
these rare and strong events that appear and disappear from nowhere result
from solitonic collisions. New developments in this subject will also be
discussed.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 31: Analysis and review of laser plasma interactions in experiments on the
National Ignition Facility
Pierre Michel*, L. Divol, S.H. Glenzer, E.A. Williams, D.A. Callahan, N.B. Meezan, R.P.J.
Town, D.E. Hinkel, J.D. Moody, E. Bond, S.N. Dixit, M.B. Schneider, E.L. Dewald, C.A.
Thomas, G.A. Kyrala2, J.L. Kline2, K. Widmann, B.J. MacGowan, M.J. Edwards, O.L.
Landen, L.J. Atherton, J.D. Lindl and L.J. Suter
Lawrence Livermore National Laboratory
2
Los Alamos National Laboratory
The National Ignition Facility (NIF), the world's largest laser with 192 beams delivering more than a
megajoule of ultraviolet energy on target, became operational in March 2009. The "hohlraum
energetics" experimental campaign was conducted from August to December 2009, and
demonstrated symmetric implosion of ignition-emulate hohlraums at radiation temperatures
suitable for ignition conditions. The first ignition experiments will begin in 2010.
Laser plasma interactions (LPI) can be important for ignition experiments. Stimulated scattering of
the laser beams in the hohlraums can cause backscatter of the laser light, which can affect the
implosion symmetry, reduce the energy coupling and generate hot electrons that can preheat the
target. On the other hand, we have also demonstrated that we can control the scattering processes
between laser beams crossing at the entrance of the hohlraums, allowing us to tune the implosion
symmetry by controlling the energy transfer between the laser beams. All these LPI processes are
diagnosed by a large number of diagnostics, analyzing the backscatter light, the hot electrons
generation, the implosion symmetry, the hohlraum radiation temperature and the brightness of the
laser beams on the hohlraum walls.
In this talk, we will review the status of LPI in the 2009 hohlraum energetics experiments. We will
present the experimental diagnostics used during the campaign, and the hydrodynamics and LPI
modeling tools used for the design and "post-shot analysis" of these experiments. We will present
our latest understanding of the hohlraum energetics campaign with respect to LPI, and explain how
we leverage our understanding of LPI to optimize the design of the forthcoming ignition
experiments on NIF.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence
Livermore National Laboratory under contract DE-AC52-07NA27344.
*email: [email protected]
Page 42
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O 32: Spike Trains of Uneven Duration and Delay: STUD pulses for the
Control of Nonlinear Optical Instabilities in Laser-Matter Interactions*
Bedros Afeyan, Marine Mardirian, Polymath Research;
Josselin Garnier, Universite Paris VI,
Stefan Hueller, Ecole Polytechnique,
Christophe Rousseaux, CEA.
We will show analytical and numerical results (And sketch out experiments that could test our
findings) on a new concept of laser-plasma instability (LPI) control in high energy density
laboratory plasmas. This new STUD pulses technique involves breaking up the continuous laser
pulse into short spikes whose durations and delays are to be adaptable to the true plasma conditions
and not what is guessed at a priori. These spike trains will modulate the laser amplitude at the
fastest growing instability growth time scale so as to make the possible growth of that instability be
limited to a prescribed number of growth times (4-8 is advised but remains adjustable). By breaking
the coherence of the drive, by allowing damping of the daughter waves to occur in between driven
sections and by moving the laser hot spots around between “on” spikes, the instabilities can be
strongly suppressed. We will show results in the weak and strong plasma wave damping regimes
(EPW or IAW), when the gain within a speckle but at the average intensity is less than 1 and up to 4
and compare our results to RPP, SSD and pseudo-STUD pulses where the laser is modulated in
time but the speckle patter is kept fixed (as in the RPP case).
These results will show that it is possible to use Green lasers for the driver of ICF and IFE with
considerable LPI control, which is thoroughly missing in current schemes touted as being LPI free.
STUD pulses also allow the control of interactions between large crossing or spatially overlapping
laser beams by controlling their overlap in space-time. This has vast consequences both for direct
and indirect drive laser fusion as well as shock and fast ignition schemes.
We will show theoretical results based on the Geometry of Gaussian Random Fields and the
statistical properties of laser hot spots with and without self-focusing, with and without plasma
inhomogeneity, with and without multiple crossing laser beams. These theoretical analyses make
predictions that could be tested in experiments we will sketch out that require 100 or more psec
long pulses which are psec time scale on-off modulated; psec time scale Thomson scattering and
backsattering measurement capability; and short pulse OPAs with tunable frequency and
wavenumber which can be used to drive background plasma waves to large levels by optical mixing
techniques.
* Work supported by DOE NNSA Joint HEDLP Program grant and a DOE OFES SBIR Phase I
grant.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 33:
Nonlinear properties of an electron plasma wave and
application to stimulated Raman scattering
Didier Benisti, Olivier Morice, Laurent Gremillet,
Evangelos Siminos
CEA, DAM, DIF F-91297 Arpajon, France
and
David J. Strozzi
Page 44
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 34:
Realistic modelling of laser-plasma interaction in hot
plasmas: toward a predictive tool?
P. Loiseau1, M. Casanova1, D. Teychenn´e1, P.-E.
Masson-Laborde1, D. Marion1,
C. Rousseaux1, S. Depierreux1, J.-P. Goossens2, D.
Pesme3 and S. H¨uller3
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 35:
Progress in modeling and understanding of parametric
instabilities in laser-plasma-interaction
P. E. Masson-Laborde1, S. H¨uller2, D. Pesme2, W.
Rozmus4,
M. Casanova1, P. Loiseau1, S. Depierreux1 and Ch.
Labaune3
Page 46
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 36:
MeV X-ray source production on Omega EP laser facility
Cédric Courtois1, Antoine Compant la Fontaine,1 Ray Edwards,2 Olivier Landoas,1 JeanLuc Bourgade,1 J. Gazave,1 S. Bazzoli1, Greg Pien,3 Dino Mastrosimone,3 C. Aedy,2
D. Drew2, M. Gardner2, A. Simons2, E. Lefebvre,1 C. Stoeckl3.
1
CEA, DAM, DIF, F-91297 Arpajon, France
AWE Plc., Aldermaston, Reading RG7 4PR, United Kingdom
3
Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
2
Results of experimental studies performed on Omega EP laser facility on multi-MeV
Bremsstrahlung x-ray source created by picosecond laser pulse are presented. Omega EP is a unique
laser facility which is able to focus kJ of laser energy in a ps time scale. The interaction of such a
high-intensity laser pulse (Il2> 1019 W.cm-2µm2) with a solid target leads to the generation of
relativistic multi-MeV electrons that can produce intense high-energy x-ray Bremsstrahlung
emission when they propagate in a (high-Z) solid target located behind the interaction area. Highenergy (>1 MeV) X-ray photon sources can be interesting for radiography applications, nuclear
activation and fission, radiation effects and radiation safety studies. In the first experiment, the short
pulse laser (Backlighter) was focused on thin gold foils 20 or 100 µm thick and delivered up to 300
J in 0.6 ps (l=1.053 µm). The second experiment was performed in a higher laser energy regime (1
kJ, 8 ps). The x-ray converter targets consisted of 2 mm thick, 2 mm diameter Ta cylinders coated
with 10 µm thick plastic (CHO).
X-ray source properties are characterized using series of diagnostics. The high energy part of
the x-ray spectrum is inferred from activation techniques using copper and carbon samples which
undergo (g,n) photo-nuclear reactions. X-ray spectrum and angular distribution of the dose are
measured with series of filtered dosimeters (image plates, OSL). Source size is inferred from the
radiography of an Image Quality Indicator (IQI) and from penumbral images that can be unfolded
to reconstruct two-dimensional images of the source with an autocorrelation method.
Results from the first campaign show a larger x-ray source with the thinnest foil (160µm
compared to 90 µm inferred from penumbral images) which could be explained by electrons
recirculation in the target. The second experiment indicates that the x-ray source temperature and
size are approximately 3.5 MeV and below 200 µm respectively which is potentially interesting for
MeV radiography with high spatial resolution. Numerical simulations performed with PIC (Calder)
and Monte Carlo (MCNP) codes are also presented.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 37: Fast electrons and high order harmonics generation from ultraintense
laser-plasma interaction
Jiansheng Liu, Wentao Wang, Changquan Xia,Cheng Wang, Ruxin Li, and Zhizhan Xu
State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy
of Sciences, Shanghai 201800, P. R. of China.
Phone: 86-21-69918187,
Fax: 86-21-69918021
[email protected]
Abstract
The interaction of ultraintense laser pulses with plasmas can generate fast electrons, monoenergetic
electron and ion beams, and intense coherent X-ray sources, which can find important applications
such as laser fusion, medical therapy and diagnostics. We have experimentally investigated angular
and energy distributions of fast electrons generated from the interaction of ultraintense laser pulses
with foil and subwavelength grating targets with various laser parameters [1,2]. A transition of the
angular distribution of outgoing fast electrons from the specular reflection direction to the target
normal has been observed for p-polarized laser irradiation. By adding a prepulse to generate
preplasma, the electron yields at the direction of the reflected laser can be greatly enhanced, and a
double-peak angular distribution is observed. In the case of subwavelength grating targets, the fast
electron beam emitted along the target surface is enhanced by more than three times in comparison
with a planar target. A more collimated electron beam can be obtained by employing a larger fnumber focusing system.
Generation of 100-MeV-scale monoenergetic electron beams is demonstrated by using laser
wakefield acceleration in high-density gas jets. Beam splitting due to the plasma instability is
observed by using backward Raman scattering. In order to obtain electron beams with much higher
energy, we generate 3-cm-long and low-density plasma channels by using ablative capillary
discharges [3]. Self guiding of a 200-TW laser pulse in the plasma channel has been observed.
Some issues on high-order harmonics emission, intense attosecond pulse and ultrabroad
supercontinuum generation from relativistic laser interaction with dense plasmas have also been
discussed [4.5].
References
1.
2.
3.
4.
5.
Wentao Wang et al., “Angular and energy distribution of fast electrons emitted from a solid surface irradiated by fs
laser pulses in various conditions”, Physics Plasmas, 17,023108 (2010).
Guangyue Hu et al., “Collimated hot electron jets generated from subwavelength grating targets irradiated by
intense short-pulse laser”, 17, 033109 (2010).
Mingwei Liu et al., “Low density and long plasma channels generated by laser transversely ignited ablative
capillary discharges”, Rev. Sci. Instrum. 81, 036107 (2010).
Jiansheng Liu et al., “Nonlinear Thomson backscattering of intense laser pulses by electrons trapped in plasmavacuum boundary”, Laser and Particle Beams, 27, 365 (2009).
Li Liu et al., “Control of single attosecond pulse generation from the reflection of a synthesized relativistic laser
pulse on a solid surface”, 15, 103107 (2008).
Page 48
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 38:
Modeling of THz emission from plasma-generating
femtosecond laser pulses with unidirectional Maxwell
equation in plasma spots and in guided geometries
I. Babushkin,1 S. Skupin,2, 3 C. Köhler,2 L. Bergé,4 and J. Herrmann5
WLMI-2010
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O 39: X-ray Thomson scattering of isochorically proton heated Boron Nitride
S. Le Pape1, P.F. Davis1, 2, P. Neumayer4, A.L. Kritcher1, 2, T. Doeppner1, 5 A. BennuzziMounaix, 5A. Ravasio, 6,7 C. Brown, D. Hochhaus4, C. Fortmann1, 3, 6 G. Gregori,
O. L. Landen1, and S. H. Glenzer1
1
Lawrence Livermore National Laboratory, P.O. Box 808,
Livermore, California 94551, USA
2
University of California, Berkeley, CA, USA
3
Physics Department, University of California Los Angeles,
Box 951547, Los Angeles, California, 90095, USA
4
Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt, Germany
5
Laboratoire pour l’Utilisation des Lasers Intenses, UMR7605, CNRS – CEA - Université Paris VI
- Ecole Polytechnique,, 91128 Palaiseau Cedex, FRANCE
6
Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
7
AWE Plc., Aldermaston, Reading RG7 4PR, United Kingdom
925-422-6201, [email protected]
Abstract. We have measured for the first time the temperature of proton heated Boron Nitride using
X-ray Thomson scattering. The experiment has been performed on the 300J, 10 ps Titan laser at
Lawrence Livermore National Laboratory. The ultra-intense laser beam was split into two beams.
30% of the energy was directed onto a 10µm Aluminum foil to generate a proton beam, and the
remaining 70% was focused onto a 10µm iron foil to generate a k-alpha backlighter at 6.4 keV. The
proton beam isochorically heats a Boron Nitride foil, creating a solid density plasma with a
temperature between 10-20 eV. X-rays are scattered from the heated target onto a curved HOPG
crystal. X ray Thomson scattering in the collective regime provides an accurate measurement of the
temperature from the ratio of up- vs. down-shifted plasmon signals. Temperature has been
measured as a function of time (from 200 to 400 ps after the proton irradiation) and proton flux (by
changing the intensity of the laser on the proton target).
*This work was performed under the auspices of the U.S. Department of Energy by the Lawrence
Livermore National Laboratory, through the Institute for Laser Science and Applications, under
contract DE-AC52-07NA27344. The authors also acknowledge support from Laboratory Directed
Research and Development Grant No. 08-LW-004.
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O 40: Time-resolved XANES to probe the structure of Warm Dense Matter
F. Dorchies1, A. Benuzzi-Mounaix2, A. Lévy2, A. Ravasio2, F. Festa2,3, N. Amadou2,
E. Brambrink2, S. Mazevet3, V. Recoules3, O. Peyrusse1, T. Hall4, M. Koenig2
1
Université de Bordeaux – CNRS – CEA, Centre Lasers Intenses et Applications (CELIA), Talence, F-33405 France
Laboratoire pour l’Utilisation des Lasers Intenses, UMR7605, CNRS-CEA-Université Paris VI-Ecole Polytechnique,
91128 Palaiseau, France
3
Département de Physique Théorique et Appliquée, Commissariat a l’Energie Atomique, 91680 Bruyères-le-Châtel,
France
4
Physics Department, University of Essex - Colchester, UK
2
The study of the so-called « Warm Dense Matter » is the subject of active experimental exploration
and theoretical analysis, since it is now possible to bring the matter in such a regime using high power laser
or X-FEL. Such a regime designs a large part of the density (0.1 to 10 times the solid density) and
temperature (0.1 to a few 10 eV) phase diagram, where the properties of the matter is still poorly understood,
although of primary importance in a wide range of physical phenomena (geophysics, astrophysics1, inertial
confinement for nuclear fusion2, laser machining, …). Here, the physics is at the crossroads of condensed
matter and plasma physics. The matter is mostly degenerated (electrons), strongly coupled (ions) and nonideal, giving rise to a great physical complexity in its simulation.
Using either isochoric heating by ultra-short and energetic pulses or high-energy laser shock
compression, one can bring the matter in such a regime, but in a transient way (10 ps to 100 ps), before
hydrodynamic expansion. Taking advantage of an ultra-short (ps) laser-plasma based X-ray source3,4, timeresolved X-ray Absorption Near-Edge Spectroscopy (XANES) can bring a lot of information at macroscopic
(temperature and density) and microscopic scales (electronic and ionic structures).
In this context, we have performed several experiments to reach the Warm Dense Matter regime and
study its properties5. Recently, an experiment has been led using the LULI2000 laser facility. An aluminum
target has been compressed and heated, through laser-shock compression, up to three times the solid density
and ~ 10 eV. Density and temperature have been characterized using optical diagnostics (VISAR and SOP)
coupled with hydrodynamic simulations. Al K-edge XANES spectra have been recorded in a various set of
thermodynamic conditions, highlighting the respective influence of density and temperature on the K-edge
shift and slope. Experimental data are supported by two types of calculations, one based on Quantum
Molecular Dynamic6, the other on a dense plasma model7.
1
T. Guillot et al., Science 286 (1999) 72.
J. Lindl et al., Phys. Plasmas 11 (2004) 339.
3
M. Harmand et al., Phys. Plasmas 16 (2009) 063301.
4
F. Dorchies et al., Appl. Phys. Lett. 93 (2008) 121113.
5
A. Mancic et al., Phys. Rev. Lett. 104 (2010) 035002.
6
V. Recoules et al., Phys. Rev. B 80 (2009) 064110.
7
O. Peyrusse, J. Phys.: Condens. Matter 20 (2008) 195211.
2
WLMI-2010
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O 41:
Collapse as a process of pulse shortening
E.A. Kuznetsov
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 42:
Statistics of strong optical turbulence
Pavel M. Lushnikov and Natalia Vladimirova
Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM 87131, USA
Phone: +1 505 277 2104
We consider the statistics of light amplitude fluctuations for the propagation of a laser beam
subjected to multiple filamentation in an amplified Kerr media, with both linear and nonlinear
dissipation. Dissipation arrests the catastrophic collapse of filaments, causingtheir disintegration
into almost linear waves. These waves form a nearly-Gaussian random field which seeds new
filaments. For small amplitudes the probability density function (PDF) of light amplitude is close to
Gaussian, while for large amplitudes the PDF has a long power-like tail which corresponds to
strong non-Gaussian fluctuations, i.e. intermittency of strong optical turbulence. This tail is
determined by the universal form of near singular filaments and the PDF for the maximum
amplitudes of the filaments.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 43:
Few-cycle optical pulse: Collapse and light bullets
Hervé Leblond1, David Kremer1, and Dumitru Mihalache2
Page 54
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WORKSHOP ON LASER-MATTER INTERACTION 2010
O 44: Extreme Optical Pulse Compression and Frequency Transformation
Nikolay N. Rosanov
Vavilov State Optical Institute
Birzhevaya Liniya 12, Saint-Petersburg, 199034 Russia
Phone: +7 812 3281093 Fax: +7 812 3285891
E-mail: [email protected]
The temporal compression of initial femtosecond pulses up to attosecond dissipative solitons is
possible on the basis of self-induced transparency in media with nonlinear amplification and
absorption [1-3]. Such few-cycle pulses with coherent spectral supercontinuum are promising for a
number of applications; on the other hand, their features reveal new peculiarities of extreme
nonlinear optics. In the talk, I describe and compare different mechanisms for few-cycle dissipative
soliton pulse formation in laser amplifiers with a coherent amplifier and an absorber. Then I present
the theoretical consideration and numerical simulation of relativistic light reflection on medium
inhomogeneities induced in a nonlinear medium by strong and ultra-short laser pulses or solitons
and moving in the medium jointly with the pulses [4, 5].
First, a matrix with active (with pump) and passive (no pump) dopants is considered. Steady-state
pulses in such a medium correspond to the condition of self-induced transparency for the passive
(absorbing) dopants which have higher concentration. However, for the active dopants the
conditions of self-induced transparency are violated: Pulses with energy exceeding a critical value
are observed to collapse. I analyze the mechanisms arresting the collapse on the basis of the 1Dwave equation for the full electric field and the Bloch equations for the passive and active dopants,
as well as for the matrix. The ultimate limits to the pulse shortening are typically given by the
matrix IR- and UV-absorption spectral bands [2].
Second, studied is propagation of strong ultra-short laser pulses in a medium with fast nonlinearity.
Laser pulse induces an inhomogeneity of the medium refraction index moving jointly with the
pulse, i.e., with relativistic speed. Reflection of an additional light radiation on such a relativistic
mirror is accompanied with a giant Doppler frequency shift, and reflection coefficient can exceed
100% under certain conditions [4]. New regimes of reflection arise when inhomogeneous
(evanescent) plane waves are involved [5]. In the talk, presented are the development of the theory
and results of computer simulation of such the parametric Doppler effect. New regime of field
accumulation near the moving strong pulse is studied. In such a way a low-frequency incident
radiation is transformed into a high-frequency radiation due to reflection on the counter-propagating
strong laser pulse. Similarly, the pulse of incident radiation is substantially compressed.
1. N.V. Vyssotina, N.N. Rosanov, V.E. Semenov. JETP Lett. 83, 337 (2006).
2. N.V. Vyssotina, N.N. Rosanov, V.E. Semenov. Opt. Spectr. 106, 713 (2009).
3. N.N. Rosanov, V.V. Kozlov, S. Wabnitz. Phys. Rev. A 81, 043815 (2010).
4. N.N. Rosanov. JETP Lett. 88, 501 (2008).
5. N.N. Rosanov. Opt. Spectr. 108, 628 (2010).
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P 1:
Advances in Optical Mixing Techniques for the Effective Control of
Parametric Instabilities in Laser-Produced Plasmas
Bedros Afeyan,* M. M. Mardirian, Polymath Research Inc., Pleasanton, CA, and
M. Shoucri, IREQ, Quebec, CA
We have made considerable progress in the taming of parametric instabilities in laser-produced
plasmas and HEDLP. One technique uses nonlinear self-sustaining structures in phase space such as
KEEN waves to suppress the nonlinear undamped-trapped particle states of electron plasma waves.
This may be an ideal method of suppressing unwanted SRS plaguing indirect drive experiments at
present. We will describe the origin of these novel objects, namely kinetic electrostatic electron
nonlinear waves and how they nonlocally affect the EPWs at twice or three times their frequency by
a novel 2:1 and 3:1 resonance between phase locked multiple harmonics of the KEEN wave and the
single mode EPW through their self-consistent E field.
Fig. 1 Shows the evolution of a pair of waves, first a KEEN wave and then an EPW. The EPW fails
to form a nonlinear state because its trapping dynamics has been disrupted by extra harmonics of
the self-consistent overall E field disallowing that precise dance between electrons and the trapping
potential. This is a novel means of snuffing out resonant waves nonlocally in phase space by the use
of these novel nonlinear nonstationary self-organized asymptotic states.
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Fig. 2 shows the density response as a function of time of the KEEN + EPW vs EPW + KEEN
driven cases in the 2:1 resonance regimes. The density response of KEEN+EPW driven pairs and
the same in the opposite order. Note how the EPW never makes it when a in 2:1 resonance KEEN
wave is present prior to the formation of the EPW, while it does, with fits and starts, in the opposite
order (bottom panels). The dotted lines are the envelopes of the drives showing their relative
amplitudes and durations.
* [email protected]
Work funded by the DOE NNSA SSAA Grants program as well as a grant from the DOE NNSAOFES Joint HEDLP Program.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
P 2:
Nonlinear Bloch equations for laser-quantum dot
interactions
Brigitte Bidégaray-Fesquet
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WORKSHOP ON LASER-MATTER INTERACTION 2010
P 3:
Scaling laws in laboratory astrophysics
Serge Bouquet, Emmanuel Falize
CEA-DAM, DIF
91297 Arpajon cedex
France
and
Claire Michaut
Laboratoire Univers et Théories (LUTH)
Observatoire de Paris-Meudon
92195 Meudon Cedex
France
In this communication, a theoretical connection between laboratory astrophysics experiments and
astrophysical phenomena (or objects) is presented. For this purpose, scaling laws based on invariance
considerations of the equations of the model are derived. A few cases are considered (purely hydrodynamic,
radiatively optically thin ...) and the way this approach works is shown in each case. Finally, specific
experiments are shown as examples of application of these scaling laws.
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
P 4:
Terahertz radiation from gas plasma, generated by linearly polarized
femtosecond pulses
D. A. Fadeev, V. A. Mironov
Institute of Applied Physics RAS, Nizhny Novgorod, 603950, Russia
* [email protected]
The significant interest to terahertz waves (the last one insufficiently explored electromagnetic
band) is concerned with it’s extremely wide applicability to the different areas of researches from
utilitarian imaging in biology and security to investigation of complex molecules in chemistry [1,2].
Some of the most promising alternative for terahertz waves generation are laser plasma methods.
The common theoretical approach to this problem is divided into three stages: a) research of selfconsistent evolution of laser pulse during the breakdown of gas b) investigation of plasma electrons
excitation mechanism c) research of self-consistent low frequency plasma oscillation and
calculation of far terahertz field.
Recently in our institute new experimental data were obtained. In the common scheme of
generation using short focal length (80-400mm) parabolic lens, short laser pulse (50fs, 2.5 mJ) with
linear polarization a radiation pattern with pronounced transverse orientation depending on optic
polarization was obtained [3]. This effect could not be explained in terms of ponderomotive force
like in [4] due to it’s cylindrical symmetry character.
Here we introduce a new model of terahertz waves generation that could describe novel
experimental data. The approach is based on Boltzman equation for electron velocity distribution
function with instantaneous appearance of electrons due the tunneling ionization of gas molecules
by laser field. Considering linearly polarized laser pulse we calculated distribution function of
electrons along velocity component corresponding to laser pulse polarization direction, assuming
distributions along other two axis to be delta functions. This effect could be effectively described in
hydrodynamic model with constant anisotropic pressure (one component in pressure tensor)
appearing with laser pulse action and non vanishing after laser pulse passes.
In this work we present all three (a,b,c) stages of analysis. The first is 2D calculation of laser
pulse focusing with breakdown of gas. Because of strong dependence of the results of third stage
analysis on plasma column parameters we included ionization damping, Kerr, and Raman responses
besides refraction of optic pulse on plasma to obtain quantitative data. The second stage is rather
analytic. Here we calculate the dependence of anisotropic pressure on laser pulse amplitude. The
third stage is full 3D calculation of plasma column dynamics excited by preset laser pulse. Thus the
third is quite qualitative. The calculated electric currents are integrated in order to obtain the far
terahertz field. The typical radiation pattern obtained from our model is in good qualitative
agreement with experimental data.
M. Tonouchi, ”Cutting-edge terahertz technology”, Nature photonics, 1, 97, 2007
K. Reimann, ”Table-top sources of ultrashort THz pulses”, Rep. Prog. Phys., 70, 1597, 2007
R. A. Akmedzanov, I. E. Ilyakov, V. A. Mironov, E. V. Suvorov, D. A. Fadeev and B. V. Shishkin, “Plasma
mechanisms of pulsed terahertz radiation generation”, Radiophysics and Quantum Electronics, 52, 7, 482-493, 2009
C. D. Amico, A. Houard, M. Franco, B. Prade, A. Mysyrowicz, ”Conical Forward THz Emission from FemtosecondLaser-Beam Filamentation in Air”, PRL, 98, 235002, 2007
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P 5:
Terahertz mode dynamics in beta- barium borate crystals
S.Vidal, J.Degert, J.Oberlé, E.Freysz
CPMOH, Bordeaux University, 351 course de Liberation, Talence 33400 France
O.Fedotova, G.Rusetsky, O.Khasanov
Belarus National Academy of Sciences, Scientific- Practical Material Research Centre,
19 Brovki str., Minsk 220072 Belarus
Nowadays terahertz (THz) time-domain spectroscopy attracts much attention of scientists
because of promising applications in fingerprint spectroscopy, environment monitoring,
semiconductor and medical imaging and law enforcement. Although many principal technical
advances had been witnessed in developing intense THz sources, there is still a strong need to
develop more powerful and tunable sources. Beta-barium borate (BBO) crystals have high impact
in harmonic frequency generation and even parametric amplifiers for this spectral range. They are
transparent and more importantly have large birefringence and strong dispersion in submillimeterwave range.
In presented work optical properties in THz range of a 200 µm-thick 29° cut BBO crystal
were measured at room temperature by means of THz time-domain spectroscopy. A THz wave with
a spectrum covering the 0.25 to 3 THz range was generated by optical rectification of a 800 nm fs
laser pulse from a Ti:sapphire regenerative amplifier in a 200 µm-thick (110) ZnTe crystal. This
wave was focused onto the sample by means of two off-axis paraboloidal mirrors. After
transmission through the sample, it was measured via electro-optic sampling in a second 200 µmthick (110) ZnTe crystal using a weak probe fs laser pulse. The refractive index and the absorption
coefficient are determined from comparison of the transmitted THz spectrum with the incident one.
In addition to this measurement, to get some insight into the dynamics of the phonon modes
interacting with the THz wave during its propagation through the crystal, we have performed
wavelet analysis of the THz waveform. THz wave form transmitted by the BBO and the
spectrogram deduced from the wavelet analysis are displayed in the figure below.
To the best of our knowledge in the BBO crystal four absorption peaks are observed at about
1.7, 2.1, 2.5 and 2.8 THz. The origin of these terahertz modes is still controversial, presumably
connecting them with translational motion of Ba ions or with librations of (B3O6)3- rings. To get
insight into the features of the phonon mode interaction among themselves and with the THz pulses
in a wide range of parameters including linear and nonlinear regimes we develop the model of two
and four coupled nonlinear forced oscillators with quadratic and cubic nonlinearities as well as
various kinds of coupling. Methods of nonlinear dynamics including construction of the phase
space trajectories, Poincaré section etc. allow us to reveal not only nonlinear resonances, their
overlapping and also chaotic oscillations.
WLMI-2010
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P 6:
Radiating Solitary Waves in Photonic Band Gap
E.Gaizauskas and A.Savickas, K.Staliunas
Page 62
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P 7:
Paths towards the generation of monochromatic ion
beams
M. Grech, S. Skupin, T. Kiefer, A. Diaw, A. Mikaberidze, R. Nuter,
L. Gremillet, E. Lefebvre, V. T. Tikhonchuk
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P 8:
All-optical steering of light via spatial Bloch oscillations
in a gas of three-level atoms
Chao Hang1;2;¤ and V. V. Konotop
Page 64
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P 9:
Theory of Plasmon-Enhanced High-Harmonic Generation in the
Vicinity of Metal Nanoparticles
Anton Husakou, Song-Jin Im, Joachim Herrmann
Max Born Institute, Max Born Str. 2a, D-12489 Berlin, Germany
Phone: +49 30 63921248, Fax: +49 30 63921289
[email protected]
Plasmonic field enhancement by metallic nanostructures plays a key role in nanooptics and
has been the subject of extensive theoretical and experimental research. Recently high-order
harmonic generation (HHG) by nJ pulses directly from a laser oscillator has been demonstrated [1]
by exploiting the local field enhancement near a metallic nanostructure. In this contribution we
present the theory of the high-harmonic generation in the vicinity of nanostructures, and apply it for
different nanostructure geometries.
Besides the electric field enhancement, the HHG in the vicinity of the nanostructures is
modified due to two facts: first, the strongly inhomogeneous plasmon-enhanced electric field
suggests that its spatial dependence should be taken into account in the description of the electron
motion; and second, one can assume that electrons which have reached the metal surface are be
absorbed and do not contribute to the HHG signal. We have developed a modification of the
Lewenstein formalism to describe both these phenomena. In Fig. 1(a), the high-harmonic spectra
are shown for weak (red curves and points), moderate (green) and strong (blue) inhomogeneity with
the parameters given in the caption. One can see that for the increased inhomogeneity, even
harmonics are generated as well as odd ones due to broken inverse symmetry. Additionally, the
cutoff is extended and becomes less pronounced for stronger inhomogeneity. The influence of
electrons being absorbed by metal surface (not shown) is similar.
(b
)
Figure 1. The influence of field inhomogeneity on the HHG (a) and the spatial distribution of the harmonic cutoff in the vicinity of the metal
nanocone (b). In (a), we consider the generation of both odd (solid curves) and even (dots) harmonics for inhomogeneous field E(t,x) =
exE(t)(1+x/dinh) with dinh = 1000 nm (red curves and points), dinh = 20 nm (green curves and points), and dinh = 5 nm (blue curves and points) in argon
by monochromatic radiation at 830 nm with the intensity of 200 TW/cm2. In (b), we consider a silver nanocone with curvature radius of the tip of 5
nm surrounded by argon and illuminated by cw radiation of 0.3 TW/cm2 at 830 nm.
In Fig. 1(b) we show the distribution of the harmonic cutoff in the vicinity of a silver
nanocone with the curvature radius of 5 nm. The significant enhancement of the electric field (up to
103 for the intensity) led to high harmonic generation of the order up to 120 for the low incident
intensity of only 0.3 TW/cm2 which can be obtained directly from the laser oscillator with MHz
repetition rate. The influence of the field inhomogeneity and the metal surface is significant in this
case: without considering them, the harmonic orders of only up to 45 are predicted. To corroborate
the validity of our modeling, we have also calculated the harmonic threshold (not shown) for the
bowtie antenna for the input intensity of 0.5 TW/cm2. We have found a harmonic cutoff at 36 nm
(Nharm = 23), which is in agreement with the experimental findings [1] (Nharm = 17).
References
1. S. Kim, J. Jin, Y.-J. Kim, I.-Y. Park, Y. Kim, and S.-W. Kim, ”High-harmonic generation by resonant plasmon field
enhancement,” Nature 453, 757-760 (2008).
2. M. Lewenstein et al., ”Theory of high-harmonic generation by low-frequency laser fields,” Phys. Rev. A 49, 2117-2132
(1994).
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P 10:
Self-compression of ultrashort pulses in media with
negative third order nonlinearity
Christian Köhler,1 Luc Bergé,2 and Stefan Skupin1, 3
Page 66
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P 11:
Coupling between Kerr-induced filamentation and
stimulated Brillouin scattering in silica
S. Mauger
,
_ L. Bergé,1 and S. Skupin2
WLMI-2010
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P 12: Development of laser plasma instabilities during the interaction of two
successive ps pulses at moderate intensity: space- and time-resolved
Thomson scattering measurements
C. Rousseaux1, S.D. Baton2, D. Bénisti1, L. Gremillet1, P. Loiseau, B. Loupias1,
F. Philippe1, F. Amiranoff2
1
2
Commissariat à l'Energie Atomique, DAM, DIF, F-91297 Arpajon, France
LULI, UMR 7605, CNRS-CEA-Ecole Polytechnique-Université Paris VI, Ecole Polytechnique, 91128
Palaiseau, France
in collaboration with J.L. Kline3, D.S. Montgomery3, B.B. Afeyan4
3
P-24, Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
4
Polymath Research Inc., 827 Bonde Court, Pleasanton, CA 94566, USA
The development and saturation mechanisms of the electron plasma waves (EPW) and ion
acoustic waves (IAW) respectively driven by stimulated Raman (SRS) and Brillouin (SBS)
backscattering are experimentally investigated using the LULI 100-TW laser facility. In this
experiment, the laser parametric instabilities (LPI) are excited by two successive 1w, 1.5 ps laser
pulses, separated by 3 or 6 ps. The pulses are fired at f/17 into a pre-ionized He plasma (ne ~ 57x1019 cm-3). Our objective is to investigate the potential coupling between the instabilities driven
by the two pulses as a function of the system parameters, to be compared with the single,
monospeckle interaction [1].
The shots are analyzed through two simultaneously operated, time-resolved (t = 300 fs),
Thomson-scattering diagnostics. The first one measures the driven IAW and EPW spectra along the
laser pump direction (z axis). The second one provides space-resolved measurements of the spectra
along the direction perpendicular to the pump direction simultaneously at two or three z locations.
The time delay between the two pulses, the initial gas pressure and the intensity of the first
pulse have been varied. Due to the moderate fixed intensity (Imax = 2x1016 W/cm2) of the second
pulse, the detected IAWs may not necessarily result from SBS. Second pulse–driven recovery of
SRS is observed at low electron density with 3 ps time delay or with 6 ps time delay at higher
electron density. As SRS saturates, the EPW spectra exhibit a surprisingly large radial extension
around the interaction volume, together with a significant frequency downshift of the EPWs which
is found to decrease with the radial distance [2] [3]. The potential implications of the experimental
measurements will be briefly discussed.
[1] C. Rousseaux et al., Phys. Rev. Lett. 97, 015001 (2006).
[2] C. Rousseaux et al., Phys. Rev. Lett. 102, 185003 (2009).
[3] C. Rousseaux et al., Anomalous 2008.
Page 68
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P 13: Stability of nonlinear Vlasov waves through Fourier-Hermite
discretization
Evangelos SIMINOS, Didier BENISTI and Laurent GREMILLET
CEA, DAM, DIF, 91297 Arpajon, France
Using an expansion in Fourier-Hermite basis we compute stability of nonlinear Vlasov waves for two
problems of relevance to stimulated Raman scattering. We calculate the growth rate of perturbations of BGK
equilibria with multiple phase space depressions (holes) that undergo a hole-fusion route to saturation,
resembling the vortex fussion observed in SRS simulations. We also present preliminary results concerning
subharmonic perturbations of large amplitude electrostatic plasma waves.
WLMI-2010
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P 14:
Self-Organized Dissipationless Ginzburg-Landau Solitons
V. Skarka1 and N. B. Aleksic2
1
Laboratoire POMA, UMR 6136 CNRS, University of Angers, 2, Boulevard Lavoisier,
49045 Angers, France
2
Institute of Physics, Pregrevica 118
Belgrade, Serbia
e-mail: [email protected]
The diffraction and dispersion of an optical pulse need to be compensated by saturating
nonlinearity, in order to be completely confined in space and time forming so-called “light bullet”.
In a real experiment, light bullet cannot propagate without losses. We demonstrated that only cross
compensation between saturating nonlinearity excess, loss, and gain maintains such self-organized
structure in stable dynamic equilibrium, on the stable brunch of bifurcation diagram. We developed
the dissipative variational method in order to find steady state solutions of complex cubic-quintic
Ginzburg-Landau equation that describe well dissipative solitonic structures of one, two, and three
dimensions. A stability criterion is established rendering a large domain of dissipative parameters
[4]. Analytically obtained symmetric steady state solutions of Ginzburg-Landau equation are stable
in this domain. If these approximate solutions are taken as input for numerical simulations of full
Ginzburg-Landau equation, their evolution will always lead to stable dissipative solitons in dynamic
equilibrium. A localized light pulse becomes a dissipationless soliton whenever the loss is
compensated by the gain and simultaneously the light dispersion is balanced by the medium
nonlinearity. It is worthwhile to stress that even very asymmetric input pulses far from stable
spherically symmetric steady states, for the same dissipative parameters from our domain, always
self-organize into solitons. Analytically obtained stable steady states are in the domain of attraction
of the exact solution. As a consequence, bullets are very robust resisting to the successive increase
of amplitude during evolution. Variety of different solitons can appear for various parameters. The
opportunity to treat analytically and numerically asymmetrical input pulses propagating toward
necessarily stable and robust dissipationless light bullets opens possibilities for diverse practical
applications including experiments.
References
[1] G. Nicolis and I. Prigogine, Self-Organization in Nonequilibrium Systems, (John Wiley and
Sons, New York, 1977).
[2] V. Skarka, V.I. Berezhiani, and R. Miklaszewski, Phys. Rev. E 56, 1080 (1997).
[3] V. Skarka, and N.B. Aleksic, Phys. Rev. Lett. 96, 013903 (2006).
[4] N.B. Aleksic, V. Skarka, D. V. Timotijevic, and D. Gauthier, Phys. Rev. A 75, 061802(R)
(2007).
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P 15: Analytical solutions for generalized nonlinear Schrodinger equation
Larisa L. Tatarinova
Theoretical Physics, University of Fribourg, Chemin du
Musee 3, 1700 Fribourg, Switzerland.
[email protected]
New approximate analytical solutions for the nonlinear Schrodinger equation in
(1+1) and (1+2) dimensions are presented. The solutions are obtained on the basis of an
extension of an approach formulated in Ref. [1]. Various particular forms of the nonlinear
refractive index and the initial intensity distribution are studied. Expressions for determining
the nonlinear self-focusing position for each situation under consideration are obtained.
Comparison with the Marburger formula and results of numerical simulations of Ref. [2] are
presented.
References
[1]. L. L. Tatarinova, M. E. Garcia, Phys. Rev. A 78 (2008) 021806(R) (1-4).
[2]. L. Berge, C. Gouedard, J. Schjodt-Eriksen, H. Ward, Physica D 176 (2003) 181- 221
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
P 16: Fast Electron Generation and Transport in Laser-Induced Shock
Compressed Plasmas
B. Vauzour1, J. J. Santos1, D. Batani2, S. D. Baton3, M. Koenig3, Ph. Nicolaï1, F. Perez3, F.
N. Beg4, C. Benedetti5, R. Benocci2, E. Brambrink3, P. Carpeggiani2, S. Chawla4, M.
Coury6, F. Dorchies1, C. Fourment1, M. Galimberti8, L. A. Gizzi9, R. Heathcote8, D. P.
Higginson4, J. J. Honrubia7, S. Hulin1, R. Jafer2, L. C. Jarrot4, L. Labate9, K. Lancaster8, P.
Köster9, A. J. MacKinnon10, P. McKenna6, A. G. McPhee10, W. Nazarov11, J. Pasley12, R.
Ramis7, Y. Rhee13, M. Rabec Le Glohaec3, C. Regan1, X. Ribeyre1, M. Richetta14, F.
Serres3, H.-P. Schlenvoigt3, G. Schurtz1, A. Sgattoni5, C. Spindloe8, X. Vaisseau1, M.
Veltcheva2, L. Volpe2, V. Yahia3
1
CELIA, Université de Bordeaux-CEA-CNRS, Talence, France,
Dipartimento di Fisica, Università di Milano-Bicocca, Milano, Italy
3
LULI, Ecole Polytechnique-CNRS-CEA-UPMC, Palaiseau, France
4
University of California, San Diego, La Jolla, USA
5
Dipartimento di Fisica, Università di Bologna, Italy
6
SUPA, Department of Physics, University of Strathclyde, Glasgow, UK
7
ETSI Aeronauticos, Universidad Politécnica de Madrid, Madrid, Spain
8
Central Laser Facility, Rutherford Appleton Laboratory, Didcot, UK
9
Intense Laser Irradiation Laboratory at INO, CNR, Pisa, Italy
10
Lawrence Livermore National Laboratory, Livermore, USA
11
University of St. Andrews, Fife, UK
12
Department of Physics, University of York, UK
13
KAERI, Republic of Korea
15
Dipartimento di Ingegneria Meccanica, Università di Roma Tor Vergata, Italy
2
The fast ignition [1] scheme which is an alternative option to the standard Inertial Confinement Fusion (ICF)
is based on deep understanding of the fast electron propagation from their generation near the critical density
(nc) to the high compressed DT core (~300nc). Although not yet be able to reproduce fusion plasma
conditions it is however possible, by varying the compression geometries, to study the fast electrons
transport in different kinds of plasmas (classic, coupled and/or degenerated) representative (with lower
temperature and density levels) either of the corona or the core of fusion targets.
In this context we report on experimental results and their interpretation of the fast electrons
transport in compressed plasmas, created by laser-induced shock propagation in both planar and cylindrical
geometry. The experiments were respectively performed at PICO2000 (LULI, France) and VULCAN TAW
(RAL, UK) laser facilities. The obtained plasmas densities and temperatures ranged from 2 to 11g/cc and 4
to 120eV depending on the initial density of the target and the compression geometry.
The planar geometry ensures wide plasma homogeneity around the propagation axis and the surfacic mass
seen by the electrons is constant during the compression. Thus changes in the electrons range are mainly
governed by collective stopping power mechanism which can be an important source of energy loss for the
electrons. An increased stopping power is identified in compressed compared to solid Al. The cylindrical
geometry allows reaching higher compression factors and electron collimation depends on density and
temperature gradients inside the target. By imaging Ka fluorescence of electron tracers we observed for the
first time a fast electron jet propagating inside a compressed target. The fraction of hot electrons crossing the
200µm target length is found to be decreasing for an increasing compression [2]. Experimental results are
compared to hydrodynamic simulations for the compression study as well as PIC and hybrid simulations for
the electronic transport.
This work constitutes a part of the experimental validation program within the Inertial Fusion Energy
European project HiPER.
[1] Tabak M. et al., Phys. Plasmas (1994)
[2]Perez F. et al., PPCF (2009)
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Notes
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Notes
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Poster
WLMI-2010
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WORKSHOP ON LASER-MATTER INTERACTION 2010
Program:
Tuesday 14th
8:45
Opening
WDM & AstroLab
Chair: P. Mora
R. P. Drake
B. Loupias
S. Brygoo
T. Vinci
break
10:30
Femto. Filaments
Chair: L. Bergé
O. Kosareva
A. Aceves
J. Kasparian
S. V. Chekalin
12:30
lunch
17:00
Ultrafast Micropr.
Wednesday 15th
8:40
Applied Math.
Chair: E. A. Kuznetsov
D. Lannes
E. Lorin
E. Dumas
R. Sentis
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break
11:00
Supercontinuum
Chair: B. Afeyan
Chair: J. Kasparian
F. Courvoisier
V. Mezentsev
S. Guizard
T. Itina
Yu. Geints
19:00
Dinner
Chair: O. Kosareva
G. Steinmeyer
E. Constant
M. Bache
V. Tosa
break
10:30
UHI
P. Mora
V. Yu. Bychenkov
S. Ter-Avetisyan
A. A. Andreev
L. Gremillet
12:30
lunch
Thursday 16th
9:00
Pulse compression
Chair: G. Steinmeyer
W. Krolikowski
A. V. Gorbach
J. Herrmann
M. Taki
12:30
lunch
17:00
ICF
Chair: R. P. Drake
17:00
Poster Session
19:00
Dinner
P. Miche
B. Afeyan
D. Benisti
P. Loiseau
P. E. Masson-Laborde
19:30
Conference Dinner
WLMI-2010
Friday 17th
8:40
X, VUV, THz
Chair: V. Yu. Bychenkov
C. Courtois
J. Liu
I. Babushkin
S. Le Pape
F. Dorchies
break
10:50
Self-focusing
Chair: S. Skupin
E. A. Kuznetsov
P. M. Lushnikov
H. Leblond
N. Rosanov
Closing
12:30
lunch