Broadband optical parametric chirped pulse amplifier insensitive to temperature
The present disclosure relates to a broadband optical parametric chirped pulse amplifier insensitive to temperature comprises the first pulsed laser, the second pulsed laser, a pulse stretcher and a periodically poled nonlinear crystal. Via the proper arrangement of the non-collinear angles between the transmission directions of the signal light, the pump light and the idler light, to simultaneously satisfy the angular relationship required for constructing the non-collinear phase-matching configuration insensitive to wavelength and that required for constructing the non-collinear phase-matching configuration insensitive to temperature, the optical parametric chirped pulse amplifier not only can realize a broadband parametric amplification of the signal light (insensitive to wavelength), but also can effectively alleviate the phase mismatch in nonlinear crystal resulted from the excessively high local temperature (insensitive to temperature).
1. A broadband optical parametric chirped pulse amplifier, capable of tolerating temperature variation in a certain range without changing an already satisfied phase-matching condition, comprising a first pulsed laser, a second pulsed laser, a pulse stretcher and a periodically poled nonlinear crystal, wherein a signal light generated by the first pulsed laser passes through the pulse stretcher, and then is coupled with a pump light generated by the second pulsed laser in the periodically poled nonlinear crystal, during a coupling process, energy is transferred from the pump light to the signal light to amplify power of the signal light and generate an idler light, wherein the signal light, the pump light and the idler light passing through the periodically poled nonlinear crystal are non-collinear, and non-collinear angles therebetween simultaneously satisfy an angular relationship required for constructing a non-collinear phase-matching configuration capable of tolerating wavelength variation in a certain range and that required for constructing a non-collinear phase-matching configuration capable of tolerating temperature variation in the certain range;
the periodically poled nonlinear crystal is a periodically poled lithium niobate crystal that satisfies a Type-0 quasi-phase matching condition, wherein the periodically poled lithium niobate crystal is 5% molar magnesium oxide (MgO) doped, a periodic grating of the periodically poled nonlinear crystal has an ability to constitute a wave-vector quadrangle with k s (T 0 ) represents a wave vector of the signal light at its central wavelength and a preset phase-matching temperature T 0 , and k p (T 0 ) represents a wave vector of the pump light at its central wavelength and the preset phase-matching temperature T 0 , and the k i (T 0 ) represents a wave vector of the idler light at its central wavelength and the preset phase-matching temperature T 0 , and k g =2π/Λ represents a grating wave vector of the periodically poled nonlinear crystal, wherein Λ represents a grating period of the periodically poled nonlinear crystal.
2. The broadband optical parametric chirped pulse amplifier of claim 1 , wherein the angular relationship required for constructing the non-collinear phase-matching configuration capable of tolerating wavelength variation in the certain range is:
v i cos β= v s ,
wherein v i represents a group velocity of the idler light, and v s represents a group velocity of the signal light;
the angular relationship required for constructing the non-collinear phase-matching configuration capable of tolerating temperature variation in the certain range is:
∂
k
p
(
T
)
∂
T
❘
T
=
T
0
cos
(
α
+
β
)
-
∂
k
s
(
T
)
∂
T
❘
T
=
T
0
cos
β
=
∂
k
i
(
T
)
∂
T
❘
T
=
T
0
,
wherein α represents an included angle between transmission directions of the pump light and the signal light, β represents an included angle between transmission directions of the signal light and the idler light, k p (T) represents a temperature-dependent wave vector of the pump light, k s (T) represents a temperature-dependent wave vector of the signal light, k i (T) represents a temperature-dependent wave vector of the idler light, T 0 represents the preset phase-matching temperature of the periodically poled nonlinear crystal, and T represents an operating temperature of the periodically poled nonlinear crystal.
3. The broadband optical parametric chirped pulse amplifier of claim 1 , wherein a tilted angle of the periodically poled nonlinear crystal is adjustable.
4. The broadband optical parametric chirped pulse amplifier of claim 1 , wherein the optical parametric chirped pulse amplifier further comprises a reflecting mirror, the pump light generated by the second pulsed laser passes through the reflecting mirror, and then is coupled with the signal light passing through the pulse stretcher in the periodically poled nonlinear crystal.
5. The broadband optical parametric chirped pulse amplifier of claim 1 , wherein the optical parametric chirped pulse amplifier further comprises a pulse compressor, the amplified signal light is compressed by the pulse compressor.
6. The broadband optical parametric chirped pulse amplifier of claim 1 , wherein the first pulsed laser is a femtosecond pulsed laser.
7. The broadband optical parametric chirped pulse amplifier of claim 6 , wherein the first pulsed laser is a mid-infrared femtosecond pulsed laser or a Ti: sapphire femtosecond pulsed laser.
8. The broadband optical parametric chirped pulse amplifier claim 1 , wherein the second pulsed laser is a picosecond pulsed laser.