Download Ultrashort approach

10 fs laser chain based on optical
parametric chirped pulse amplification
Lourdes Patricia Ramirez
Equipe Lasers Solides et Applications
Laboratoire Charles Fabry de l’Institut d’Optique (LCFIO), Palaiseau, France
Frédéric Druon
Directeur de thèse
Journées Scientifiques de l’EDOM
March 8, 2011
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Outline
• Motivation: Front end of the Apollon laser
• Optical parametric chirped pulse amplification (OPCPA)
• Seed source for OPCPA
Ultrashort approach
Direct XPW approach
• Summary and future work
Journées Scientifiques de l’EDOM
March 8, 2011
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Front end of the Apollon 10 PW laser
Ultrashort seed source @ 800 nm
High contrast, CEP stable,
sub-10 fs, >100 µJ, 1 kHz
Noncollinear Optical
Parametric Chirped Pulse
Amplification stages
NOPCPA
(BBO or LBO)
Optical synchronization
<10 fs, 100 mJ,
@800 nm, 10-100 Hz
10 TW!
HEC-DPSSL pumped
high rep-rate amplifiers
(Yb:KGW, YAG, CaF2)
2 J @ 1030 nm, 10-100 Hz
SHG: ps-ns
1 J @ 515 nm
10-100 Hz
Pump source @ 515 nm
Applications: high harmonic generation, attosecond physics, particle acceleration, plasma
physics, high energy physics experiments
Journées Scientifiques de l’EDOM
March 8, 2011
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Optical parametric amplification (OPA)
Generation
pump
Nonlinear
Crystal
X(2)
 p  s  i
Amplification
pump
signal
Nonlinear
Crystal
X(2)
• Extremely broad
amplification bandwidth
signal
• High gain per single pass
• High quantum efficiency
idler
• Low thermal effects
• Reduced amplified
spontaneous emission –
high energy and
intensity contrast ratio
residual pump
pulses
• Scalability to high
amplified signal
energies
idler
Journées Scientifiques de l’EDOM
March 8, 2011
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Chirped pulse amplification (CPA)
Journées Scientifiques de l’EDOM
March 8, 2011
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OPA + CPA = OPCPA
Replace with nonlinear crystals
e.g. BBO, LBO, KDP
Journées Scientifiques de l’EDOM
March 8, 2011
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Front end of the Apollon 10 PW laser
Ultrashort seed source @ 800 nm
High contrast, CEP stable,
sub-10 fs, >100 µJ, 1 kHz
Noncollinear Optical
Parametric Chirped Pulse
Amplification stages
NOPCPA
(BBO or LBO)
Optical synchronization
<10 fs, 100 mJ,
@800 nm, 10-100 Hz
10 TW!
HEC-DPSSL pumped
high rep-rate amplifiers
(Yb:KGW, YAG, CaF2)
2 J @ 1030 nm, 10-100 Hz
SHG: ps-ns
1 J @ 515 nm
10-100 Hz
Pump source @ 515 nm
Journées Scientifiques de l’EDOM
March 8, 2011
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Ultrashort seed source
• Sub-10 fs , >100 µJ, 1 kHz, CEP stable, high contrast ratio at 800 nm
• 2 approaches:
Commercial ultrashort Ti:Sa system
25 fs, 1.5 mJ, 1 kHz,
CEP stable, CR ~ 108
Ultrashort approach: 5 fs
Hollow core fiber (HCF) pulse compression
Cross polarized wave generation (XPW)
5 fs, 100 µJ, CEP preserving, CR ~ 1010
Main disadvantages: low efficiency
- Compression in between two stages
Journées Scientifiques de l’EDOM
March 8, 2011
Direct XPW: Sub-10 fs approach
Spectral broadening and contrast enhancement
via cross polarized wave generation only
< 10 fs, 200-300 µJ, CEP preserving, CR ~ 1010
Advantages: higher efficiency
- Single stage for broadening and contrast
enhancement
- Simple and compact setup
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Ultrashort approach: hollow fiber compression
1.4mJ, 25fs
>850 µJ
>750 µJ
Pulse compression:
25 fs to 4.4 fs
Spectral broadening in the HCF:
60 nm to 250 nm
25
1.0
1.0 HCF 250µm diam, 1m long, 1.3bar Ne:
----Ein=1.3 mJ (~48nm)
----Eout=0.8mJ (~250nm)
0.8
60nm
250 nm
0.4
20
0.6
0.4
15
0.2
0.2
0.0
0.0
500
Phase (rad)
0.6
Laser
HCF
Intensity (a.u.)
Intensity (a.u.)
0.8
10
600
700
800
Wavelength (nm)
Journées Scientifiques de l’EDOM
March 8, 2011
900
1000
-30
-20
-10
0
10
20
30
Time (fs)
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Cross polarized wave generation (XPW)
XPW is based on a degenerated four-wave mixing process governed by the
anisotropy of the real part of a crystal’s third-order nonlinearity tensor.
I XPW (t )  I L 3 (t )
χ(3)
Glan 1
BaF2
Glan 2
Main features:
- Contrast enhancement: depends on the polarizer exctinction ratio (105)
t 3
- Temporal pulse shortening:
- Spectral cleaning and broadening  3
Journées Scientifiques de l’EDOM
March 8, 2011
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Ultrashort approach: HCF + XPW
~550μJ, 5fs
~80 μJ, 5fs
~100μJ
Energy/Spectrum
FROG
3ω/f-2f
Spectral cleaning with XPW:
250 nm to 200 nm
Compression: 5 fs
60
1.0
50
0.8
XPW
HCF
30
0.4
20
0.2
10
-20
-10
0
Time (fs)
Journées Scientifiques de l’EDOM
March 8, 2011
Main result:
HCF + XPW
5 fs, 100 μJ
0
0.0
-30
Phase (rad)
Intensity (a.u.)
40
0.6
10
20
30
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Direct XPW
Filtered spatial
profile of laser
beam
Actual spatial
profile of laser
beam
1.5 mJ
25 fs
f = 1.5 m
f
Spatial
profile of
XPW beam
25-41 cm
300 μJ
f
XPW
20-cm hollow core
waveguide
Spectral broadening with XPW:
60 nm to 140 nm
2.5-mm BaF2
Polarizer
Pulse compression with XPW:
25 fs to 9.6 fs
Main result:
Direct XPW
9.6 fs, 300 μJ!
Journées Scientifiques de l’EDOM
March 8, 2011
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Summary and future work
• Implemented two seed sources for an OPCPA based laser
chain.
- Hollow core fiber compression and cross polarized wave
generation: 5 fs, 100 µJ, 10-10 contrast ratio
- Direct cross polarized wave generation: 9.6 fs, 300 µJ, 10-10
contrast ratio
• Improving the stability and reliability of the direct XPW seed
source
• Developing a stretcher for the seed source
• Perform OPCPA
Journées Scientifiques de l’EDOM
March 8, 2011
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Merci pour votre attention!
Journées Scientifiques de l’EDOM
March 8, 2011
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Ultrashort approach: contrast
HCF
XPW
- Pre-pulses are removed.
- Contrast ratio is estimated to be 10-10.
Journées Scientifiques de l’EDOM
March 8, 2011
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