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Curso de Métodos experimentales
En la Física PCF UNAM
Cuernavaca, Agosto 2008
cuarta semana
Dr. Antonio M. Juárez Reyes, ICF UNAM
Física Atómica, Molecular y óptica.
Cuernavaca, Agosto 2008
TEMARIO PARTE 1
I.- Instrumentos y conceptos básicos (Toño, 5 semanas)
I.1.- Conceptos básicos de instrumentación
-Conceptos generales de seguridad en el laboratorio (eléctrica, de gases
comprimidos, láseres y químicos.
--El proceso de medida y asignación de incertidumbres.
I.2.- Instrumentos básicos
2.1 sistemas de vacío.
-Conductancia, velocidad de bombeo, viscosidad,
-bombas: Rotatorias, de diafragma, difusoras, turbo, de sublimación,
ionicas. razón de compresión en bombas,
- transductores de presión, pirani, Bayer Alpert, Baratrón, análisis de
gases
residuales.
2.2 Instrumentos básicos de electrónica:
-osciloscopios, generadores de señales,
electrómetros,
2.3 Instrumentos avanzados
-Amplificador Lock In
-Integrador Boxcar
-Monocromadores
Cuernavaca, Agosto 2008
I.3.- Conceptos generales de láseres y fuentes de luz:
- Cavidades, ganancia y finesa
-Etalones de Fabri Perot,
-Quarter wave plates, half wave plates, Stokes parameters
-Optoacustic modulators
-Dicroic mirrors
-Láseres pulsados de nitróngeno, Nd:YAG, pulsadores del tipo Q-Switch,
láseres de diodo de cavidad extendida,
-Otras fuentes de luz: sincrotrónesy Free electron Lasers,
I.4.-Conceptos generales de diseño: herramientas de dibujo, herramientas de
simulación de circuitos, criterios generales de diseño de piezas asociadas a
instrumentación científica.
El taller de electrónica y el taller de mecánica del ICF
1.5 Elección del proyectos semestrales de instrumentación
Cuernavaca, Agosto 2008
-Interferómetro de Fabri-Perot ( etalon)
A Fabry–Pérot interferometer (also called Fabry–Pérot resonator)
is a linear optical resonator (or cavity) which consists of two
highly reflecting mirrors (with some small transmittivity) and is
often used as a high-resolution optical spectrometer. One exploits
the fact that the transmission through such a resonator exhibits
sharp resonances and is very small between those.
Cuernavaca, Agosto 2008
-Interferómetro de Fabri-Perot ( etalon)
For optical spectrum analysis, the Fabry–Pérot
interferometer is often made short enough to achieve a
sufficiently large free spectral range; the bandwidth of the
resonances is then the free spectral range divided by the
finesse
Figure 2: Frequency-dependent transmission of a linear Fabry–Pérot cavity with mirror
reflectivities of 90%.
Cuernavaca, Agosto 2008
-Interferómetro de Fabri-Perot ( etalon)
free spectral range; The free spectral range of an optical resonator (cavity) is the
frequency spacing of its axial (Gaussian-shaped) resonator modes. It is therefore also called axial mode
spacing. For an empty standing-wave resonator of length L, it can be calculated as
Bandwidth the width of the frequency range which can be transmitted by some element, e.g. an optical fiber
Finesse The finesse of an optical resonator (cavity) is defined as its free spectral range divided by the (full width
at half-maximum) bandwidth of its resonances.
Figure 2: Frequency-dependent transmission of a linear Fabry–Pérot cavity with mirror
reflectivities of 90%.
Cuernavaca, Agosto 2008
-Interferómetro de Fabri-Perot ( etalon)
Finesse The finesse of an optical resonator (cavity) is defined as its free spectral range divided by the (full width
at half-maximum) bandwidth of its resonances.
If a fraction ρ of the circulating power is left after one round-trip (i.e., a fraction
1 − ρ of the power is lost), assuming that there is no incident field from outside
the resonator, it can be shown that the finesse, F can be given by:
Figure 2: Frequency-dependent transmission of a linear Fabry–Pérot cavity with mirror
reflectivities of 90%.
Cuernavaca, Agosto 2008
-Interferómetro de Fabri-Perot ( etalon)
Finesse The finesse of an optical resonator (cavity) is defined as its free spectral range divided by the (full width
at half-maximum) bandwidth of its resonances.
If a fraction ρ of the circulating power is left after one round-trip (i.e., a fraction
1 − ρ of the power is lost), assuming that there is no incident field from outside
the resonator, it can be shown that the finesse, F can be given by:
A high finesse can be useful for optical spectrum analysis, because it allows the combination of a large free
spectral range with a small resonator bandwidth. Therefore, a high spectral resolution in a wide spectral range
is possible.
Cuernavaca, Agosto 2008
-Interferómetro de Fabri-Perot ( etalon)
Cuernavaca, Agosto 2008
Cuernavaca, Agosto 2008
I.3.- Conceptos generales de láseres y fuentes de luz:
- Cavidades, ganancia y finesa
-Etalones de Fabri Perot,
-Quarter wave plates, half wave plates, Stokes parameters
-Spacial filters
-Optical modulators
-Dicroic mirrors
-Láseres pulsados de nitróngeno, Nd:YAG, pulsadores del tipo Q-Switch,
láseres de diodo de cavidad extendida,
-Otras fuentes de luz: sincrotrónesy Free electron Lasers,
Cuernavaca, Agosto 2008
-Quarter wave plates, half wave plates, Stokes parameters
Optical waveplates (also called wave plates or retarder
plates) are transparent plates with a carefully adjusted
birefringence, which are mostly used for manipulating the
polarization state of light beams.
A waveplate has a slow axis and a fast axis, both being
perpendicular to the surface and the beam direction, and
also to each other. The phase velocity of light is slightly
higher for polarization along the fast axis.
This induces a Phase shift between orthogonal components
Of light
Cuernavaca, Agosto 2008
-Quarter wave plates, half wave plates, Stokes parameters
A waveplate has a slow axis and a fast axis, both being
perpendicular to the surface and the beam direction, and
also to each other. The phase velocity of light is slightly
higher for polarization along the fast axis.
This induces a Phase shift between orthogonal components
Of light
The wave plate is characterized by the amount of relative
phase Γ; that it imparts on the two components, which is
related to the birefringence Δn and the thickness L of the
crystal by the formula
Cuernavaca, Agosto 2008
Exercise: Proof that, considering
Is the phase shift induced by
A biorrefringent material with
A given ∆n
Then:
Phase velocity
Refractive index
The most common types of waveplates are quarterwave plates (λ/4 plates) and half-wave plates (λ/2
plates), where the difference of phase delays between
the two linear polarization directions is π/2 or π,
respectively
Cuernavaca, Agosto 2008
Ok, this is interesting, but, how does one use waveplates?
•When the plate is a half-wave plate(π -shift), then the polarization stays li
but the polarization direction is rotated. For example, for an angle of 45°
to the axes, the polarization direction is rotated by 90°.
•When the incident polarization is at an angle of 45° to the axes, a
quarter-wave (π /2 shift)plate generates a state of circular polarization.
(Other input polarizations lead to elliptical polarization states.)
Conversely, ccircularly polarized light is converted into linearly polarized
light.
See mathematica ...
Cuernavaca, Agosto 2008
Ok, this is interesting, but, how does one use waveplates?
Waveplates are in a few words, the tools one uses to
Manipulate the state of light.
Remember that a general polarization state is expressed
In terms of the Stokes Parameters.
See Stokes parameter .PDF …
Cuernavaca, Agosto 2008
-Optical modulators
Cuernavaca, Agosto 2008
An optical modulator is a device which can be used for
manipulating a property of light – often of an optical beam, e.g.
a laser beam.
Depending on which property of light is controlled, modulators
are called intensity modulators, phase modulators, polarization
modulators, spatial light modulators, etc.
A wide range of optical modulators are used in very different
application areas, such as in optical fiber communications,
displays, for active Q switching or mode locking of lasers, and
in optical metrology.
Cuernavaca, Agosto 2008
Types of Optical Modulators
There are very different kinds of optical modulators:
Acousto-optic modulators are based on the acousto-optic effect.
They are used for switching or continuously adjusting the
amplitude of a laser beam, for shifting its optical frequency, or its
spatial direction.
Electro-optic modulators exploit the electro-optic effect in a
Pockels cell. They can be used for modifying the polarization,
phase or power of a beam, or for pulse picking in the context of
ultrashort pulse amplifiers.
Electroabsorption modulators are intensity modulators, used e.g.
for data transmitters in optical fiber communications.
Interferometric modulators, e.g. Mach–Zehnder modulators, are
often realized in photonic integrated circuits for optical data
transmission.
Cuernavaca, Agosto 2008
Acousto-optic Modulators
An acousto-optic modulator (AOM) is a device which can be used for
controlling the power, frequency or spatial direction of a laser beam with
an electrical drive signal. It is based on the acousto-optic effect, i.e. the
modification of the refractive index by the oscillating mechanical pressure
of a sound wave.
Cuernavaca, Agosto 2008
Acousto-optic Modulators
The key element of an AOM is a transparent crystal (or piece of glass)
through which the light propagates. A piezoelectric transducer attached to
the crystal is used to excite a sound wave with a frequency of the order
of 100 MHz. Light can then experience Bragg diffraction at the periodic
refractive index grating generated by the sound wave; therefore, AOMs
are sometimes called Bragg cells
Cuernavaca, Agosto 2008
Acousto-optic Modulators
The scattered beam has a slightly modified optical
frequency (increased or decreased by the frequency of the
sound wave) and a slightly different direction.
The frequency and direction of the scattered beam
can be controlled via the frequency of the sound
wave
Cuernavaca, Agosto 2008
Electro-optic modulators
Cuernavaca, Agosto 2008
Electro-optic modulators
An electro-optic modulator (EOM) (or electrooptic
modulator) is a device which can be used for
controlling the power, phase or polarization of a laser
beam with an electrical control signal.
typically contains one or two Pockels cells,
and possibly additional optical elements such
as polarizers.
The principle of operation is based on the linear electro-optic effect
(also called the Pockels effect), i.e., the modification of the
refractive index of a nonlinear crystal by an electric field in
proportion to the field strength.
Cuernavaca, Agosto 2008
Electro-optic modulators
An electro-optic modulator (EOM) (or electrooptic
modulator) is a device which can be used for
controlling the power, phase or polarization of a laser
beam with an electrical control signal.
typically contains one or two Pockels cells,
and possibly additional optical elements such
as polarizers.
The principle of operation is based on the linear electro-optic effect
(also called the Pockels effect), i.e., the modification of the
refractive index of a nonlinear crystal by an electric field in
proportion to the field strength.
Cuernavaca, Agosto 2008
Electro-optic modulators
A Pockels cell is a device consisting of an electro-optic crystal
(with some electrodes attached to it) through which a light beam
can propagate. The phase delay in the crystal (→ Pockels effect) can
be modulated by applying a variable electric voltage.
Only non-centrosymmetric materials (mostly crystals) exhibit the
linear electro-optic effect, also called the Pockels effect, where the
refractive index change is proportional to the electric field strength
Cuernavaca, Agosto 2008
Electro-optic modulators
The Pockels effect (first described in 1906 by the
German physicist Friedrich Pockels) is the linear
electro-optic effect, where the refractive index of a
medium is modified in proportion to the applied electric
field strength.
This effect can occur only in non-centrosymmetric materials. The most
important materials of this type are crystal materials such as lithium
niobate (LiNbO3), lithium tantalate (LiTaO3), potassium di-deuterium
phosphate (KD*P), β-barium borate (BBO), potassium titanium oxide
phosphate (KTP), and compound semiconductors such as gallium
arsenide (GaAs) and indium phosphide (InP).
Cuernavaca, Agosto 2008
Other optical modulators
An electroabsorption modulator (or electro-absorption
modulator) is a semiconductor device which can be
used for controlling (modulating) the intensity of a
laser beam via an electric voltage
Its principle of operation is based on the Franz–Keldysh effect [1, 2],
i.e., a change in the absorption spectrum caused by an applied electric
field, which changes the bandgap energy
[1]L. V. Keldysh, “Behaviour of non-metallic crystals in strong electric fields”, J. Exp. Theor. Phys. (USSR)
33, 994 (1957); translation: Sov. Phys. JETP 6, 763 (1958)
Cuernavaca, Agosto 2008
Electro-optic modulators
The Pockels effect (first described in 1906 by the
German physicist Friedrich Pockels) is the linear
electro-optic effect, where the refractive index of a
medium is modified in proportion to the applied electric
field strength.
This effect can occur only in non-centrosymmetric materials. The most
important materials of this type are crystal materials such as lithium
niobate (LiNbO3), lithium tantalate (LiTaO3), potassium di-deuterium
phosphate (KD*P), β-barium borate (BBO), potassium titanium oxide
phosphate (KTP), and compound semiconductors such as gallium
arsenide (GaAs) and indium phosphide (InP).
Cuernavaca, Agosto 2008
Electro-optic modulators
Mathematically, the Pockels effect is best described via
the induced deformation of the index ellipsoid, which
is defined by
in a Cartesian coordinate system. An electric
field can now change the coefficients
according to
Cuernavaca, Agosto 2008
Electro-optic modulators
Figure 1: Pockels cells of various
types.
Cuernavaca, Agosto 2008
-Dicroic mirrors
Cuernavaca, Agosto 2008
-Dicroic mirrors
Definition: mirrors with significantly different
reflection or transmission properties at two
different wavelengths
Cuernavaca, Agosto 2008
-Dicroic mirrors
Definition: mirrors with significantly different
reflection or transmission properties at two
different wavelengths
Figure 1: Reflectivity spectrum of a dichroic mirror coating, designed for high transmission (low
reflectivity) around 808 nm and high reflectivity at 1064 nm.
Cuernavaca, Agosto 2008
-Dicroic mirrors
A dielectric mirror consists of multiple thin layers
of (usually two) different transparent optical
materials (→ dielectric coatings, thin-film
coatings, interference coatings).
Dielectric coatings, also called thin-film coatings or interference
coatings, consist of thin (typically sub-micron) layers of transparent
dielectric materials, which are deposited on a substrate. Their function is
essentially to modify the reflective properties of the surface by exploiting
the interference of reflections from multiple optical interfaces.
Cuernavaca, Agosto 2008
-Dicroic mirrors
Even if the Fresnel reflection coefficient from a single interface
between two materials is small (due to a small difference in
refractive indices), the reflections from many interfaces can (in
a certain wavelength range) constructively interfere to result in a
very high overall reflectivity of the device.
he simplest and most common design is that of a Bragg mirror,
where all optical layer thickness values are just one-quarter of
the design wavelength.
Cuernavaca, Agosto 2008
-Dicroic mirrors
A Bragg mirror (also called distributed Bragg reflector) is a
structure which consists of an alternating sequence of layers of
two different optical materials.
The most frequently used design is that of a quarter-wave
mirror, where each optical layer thickness corresponding to one
quarter of the wavelength for which the mirror is designed.
Cuernavaca, Agosto 2008
-Dicroic mirrors
The principle of operation can be understood as follows. Each
interface between the two materials contributes a Fresnel
reflection. For the design wavelength, the optical path length
difference between reflections from subsequent interfaces is half
the wavelength; in addition, the reflection coefficients for the
interfaces have alternating signs.
Cuernavaca, Agosto 2008
-Dicroic mirrors
Figure 1: Field penetration into a
Bragg mirror.
The intensity distribution inside the
dielectric mirror can be rather complex!
Cuernavaca, Agosto 2008
More complex separations cangive rise to mirrors which
Reflect over a wide band of frequencies
Figure 3: Field penetration into the Bragg
mirror as a function of wavelength. The colors
indicate the optical intensity inside the mirror.
Cuernavaca, Agosto 2008
-Zone Plates
Cuernavaca, Agosto 2008
-Zone Plates
A zone plate is a device which focuses light using diffraction
instead of refraction.
They were devised by by Augustin-Jean Fresnel and are also
called Fresnel zone plates For this reason
A zone plate consists of a set of radially symmetric rings, known as Fresnel zones, which
alternate between opaque and transparent. Light hitting the zone plate will diffract around the
opaque zones. The zones can be spaced so that the diffracted light constructively interferes at
the desired focus,
Cuernavaca, Agosto 2008
-Zone Plates
A zone plate consists of a set of radially symmetric rings, known as Fresnel zones, which
alternate between opaque and transparent. Light hitting the zone plate will diffract around the
opaque zones. The zones can be spaced so that the diffracted light constructively interferes at
the desired focus,
Fuentes de luz UV.
1.- Introducción
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia.
2.2 Propiedades de la radiación sincrotrónica
2.3 Aplicaciones y usos.
3.- Fotoionización de hidrógeno molecular, H2.
3.1 Ortho y para-hydrógeno: O, de como la estadística Fermi-Dirac
nos brinda dos tipos de moléculas de H2.
3.2 Como obtener para-H2 a partir de H2 normal.
3.3. Medición de niveles rotacionales en para-H2 usando radiación
sincrotrónica.
1. Introducción
*
La investigación basica inicia como un ejercicio de
curiosidad… e inevitablemente se traduce en
aplicaciones en campos diversos y distintos del original.
El desarrollo de fuentes de luz , como el laser y la radiacion
sincrotrónica (de la que hablaremos en esta plática) son
ejemplos de lo anterior.
1. Introducción.
Que cosa es, antes que nada, la radiacion sincrotrónica
Brevemente, se puede definir como la radiación
electromagnética emitida por un electrón que se acelera
mientras viaja a velocidades cercanas a la velocidad de
la luz, C .
Esta radiación va de el infrarrojo a los rayos X (pasando
por el ultravioleta) , es continua en frecuencia y muy
intensa.
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
El fenomeno de difracción de
Bragg…..
...Así como el descubrimiento de
la doble hélice de ADN.
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
A pesar de esa importancia, las
fuentes de luz en el utravioleta y
los rayos X estuvieron limitadas
por más de medio siglo a
fuentes relativamente débiles, y
que emitían luz en unas cuantas
frecuencias...
Aparato de rayos X (esquema)
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
El interés en colisiones a altas energías
en la década de los 50´s llevo a los
físicos a desarrollar aceleradores que
permitieran realizar colisiones frontales
entre partículas a velocidades enormes (
y observar los productos resultantes)
Las partículas se hacen girar en
órbitas circulares opuestas, y se
hacen colisionar en lugares
específicos del tunel.
Tunel en CERN
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
En 1947 (mientras se pretendia
hacer otra cosa), técnicos y
cientificos de la General electrics
descrubrieron la radiación
sincrotrón.
Esto fue un tanto accidental puesto
que la cámara de vacío del
acelerador era de vidrio.
A la radiación descubierta se le
llamo inicialmente Radiación de
Schwinger
Luz emanando del famoso
acelerador en laboratorios
de la General Electrics.
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
Cuando fue evidente que los
usos de la radiación
sincrotrón merecian un
acelerador por derecho
propio, aceleradores mas
eficientes fueron
desarrollados con el objetivo
específico de aprovechar al
máximo las ventajas de la
radiación sincrotrónica.
Laboratorio de Daresbury
(Segunda generación)
Laboratorio Bessy, Berlin.
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
Estas fuentes de segunda
generación producen luz
sincrotrón acelerando electrones
con imanes de alta intensidad de
campo magnético.
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
Avances ulteriores en el diseño de imanes arreglados
en forma periódicos, así como de óptica optimizada
para su uso en el ultravioleta y los rayos X llevaron al
desarrollo de fuentes cada vez mas brillantes y
especializadas, que constituyen las fuentes de “tercera
generación”.
Estas fuentes se
caracterizan por el uso
de “elementos de
inserción”
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
La periodicidad del
campo magnético se
arregla de tal manera
que los electrones
realicen una
oscilacion sinusoidal.
En cada punto de
inflexión de esta
trayectoria ondulante
los electrones emiten
radiación
Si el período del los imanes se elige adecuadamente, se conseguirá interferencia
constructiva. Esto su vez lograra que se multiplique en órdenes de magnitud, la intensidad
de a luz producida.
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
Los sincrotrones que basan su operacion en el uso de
elementos de inserción se les denomina de “tercera
generación”
Sincrotrón Elettra, Trieste,Italia
ALS, Berkeley, vista
de una estación
experimental
2.- Principios básicos de radiación sincrotrónica.
2.1 Un poco de historia...
Cuarta generación… Fuentes de radiación sincrotrón por
electrones libres.
Aunque los laseres de electrones libres ya existen, las
fuentes de cuarta generacion planean extender sus
rangos espectrales al UV y los rayos X (4GLS)
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
2.2 Propiedades de la radiación sincrotrónica
Electrodinámica no-relativista
Un electron, de carga e, que es acelarado con
aceleracion a, radia energia electromagnética en
distintas direcciones. En particular, la potencia por
unidad de angulo sólido esta dada por la siguiente
expresion:
2
2
dP
r 2a

dΩ 16π ε
3
o
c
sin
2
Θ
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
sin 
tan  
   cos 
Donde Θ es el ángulo de un observador en reposo y
Θ ´es el angulo medido en el sistema de referencia
que se mueve.
Ademas: =v/c y =1/(1-v2/c2)1/2
Para apreciar de manera fácil que pasa con la radiación
emitida por un electron relativista, tal como es vista por
un observador en reposo, basta observar que, en el
limite relativista, 1, >>1
En este limite, Θ queda acotado por el valor maximo 1/ 
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
Comparación de los patrones de radiación electromagnética entre (a) un
electron que se observa en el mismo sistema de referencia y (b) un
electrón que se mueve a velocidades relativistas, desde un sistema de
referencia fijo en el laboratorio.
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
2.2.2. Composición espectral de la radiación
sincrotrónica.
Por que es continua la luz sincrotrón?
Debido a que la radiación
es emitida en un cono de
luz, un observador fijo
vería, conforme el electrón
gira en su órbita, un pulso
de luz solo cuando el
electrón pasara frente al
observador, como se
muestra en la figura 2.
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
2.2.2. Composición espectral de la radiación sincrotrónica.
Un argumento físico sencillo para explicar la presencia de
un continuo de colores en la radiación sincrotron es,
notando que el tiempo de tránsito del electrón para un
observador fijo es:
R
2t 
2c 3
Recordando que: Et=/2
Entonces:
E 
2c

R
3
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
Free Electron Lasers
Definition: laser devices where light
amplification occurs by interaction with
fast electrons in an undulator
Figure 1: Setup of an undulator, as
used in a free electron laser. The
periodically varying magnetic field
forces the electron beam (blue) on a
slightly oscillatory path, which
leads to emission of radiation.
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
Free Electron Lasers
Definition: laser devices where light
amplification occurs by interaction with
fast electrons in an undulator
Figure 1: Setup of an undulator, as
used in a free electron laser. The
periodically varying magnetic field
forces the electron beam (blue) on a
slightly oscillatory path, which
leads to emission of radiation.
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
Free Electron Lasers
Definition: laser devices where light
amplification occurs by interaction with
fast electrons in an undulator
A free electron laser is a relatively exotic type of laser where
the optical amplification is achieved in an undulator, fed with
high energy (relativistic) electrons from an electron accelerator.
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
uch devices have been demonstrated with emission
wavelengths reaching from the terahertz region via
the far- and near-infrared, the visible and ultraviolet
range to the X-ray region
K.-J. Kim and A. Sessler, “Free-electron lasers: present
status and future prospects”, Science 250, 88 (1990)
G. R. Neil and L. Merminga, “Technical approaches for
high-average-power free-electron lasers”, Rev. Mod. Phys.
74, 685 (2002)
W. Ackermann et al., “Operation of a free-electron laser
from the extreme ultraviolet to the water window”, Nat.
Photonics 1, 336 (2007)
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
The underlying principle of the intense pulses from the
X-ray laser lies in the principle of Self-Amplified
Stimulated-Emission which leads to the
microbunching of the electrons.
Self-Amplified Spontaneous (or Stimulated) Emission
(SASE) is a process within a Free electron laser (FEL)
by which a laser beam is created by the high-energy
electron beam.
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
The underlying principle of the intense pulses from the
X-ray laser lies in the principle of Self-Amplified
Stimulated-Emission which leads to the
microbunching of the electrons.
Self-Amplified Spontaneous (or Stimulated) Emission
(SASE) is the process responsible of the coherence
and laser-like properties present in a Free electron
Laser
2.- Principios básicos de radiación sincrotrónica.
2.2 Propiedades de la radiación sincrotrónica
Free Electron Lasers
El ancho de banda
proporcionado por la
radiación (del infrarrojo
a los rayos X duros, e
incluso gamma, no
puede obtenerse de
ninguna otra fuente
hecha por el hombre…
de ahí su importancia
práctica …
2.- Principios básicos de radiación sincrotrónica.
2.3 Algunas aplicaciones de la radiación sincrotroón
2.3 Aplicaciones
2.3 lista breve de algunos usos y aplicaciones de
radiación sincrotrónica.
1.- Caracterizacion de esfuerzos de tension y esfuerzo
de materiales. Por ejemplo, en alas de aviones (airbus,
en sus esudios de aleaciones para sus nuevos modelos)
Estudios de difracción de
rayos X de las juntas de
componentes críticas.
(valido par un sinfín de
materiales.. Acero,
concreto…
2.- Principios básicos de radiación sincrotrónica.
2.3 Algunas aplicaciones de la radiación sincrotroón
2.- Estudio de la estructura por difracción de rayos
X, de proteínas de importancia biológica, como la
hemoglobina y la insulina.
3.- Estudio de fotoionización, disociación,
recombinación de moléculas y radicales libres de
importancia atmosférica ( O2, O3, SO2, NO, N2O,
NO2) .
2.- Principios básicos de radiación sincrotrónica.
2.3 Algunas aplicaciones de la radiación sincrotroón
Litografía con ultravioleta para desarrollo de
microcomponentes, memorias magneticas de alta
densidad, estudio de nanoestructuras, orientacion de
cristales líquidos… la lista es tan grande como uno
quiera.