Noise filtering in parametric amplification by dressing the seed beam with spatial chirp

Abstract

We report a method for filtering out the noises produced in optical parametric chirped-pulse amplifiers by dressing the seed beam with spatial chirp. After dechirping the amplified signal with a compressor, the noises experience a spatiotemporal coupling, making themselves highly distinguishable from the compressed signal in space, and hence supporting noise filtering effectively and expediently in the spatial domain, which would otherwise not be possible. Numerical simulations performed for the proposed method show the capabilities of an order of magnitude reduction in the noise energy and several orders of magnitude enhancement in the temporal contrast.

Further Development of the Short‐Pulse Petawatt Laser: Trends, Technologies, and Bottlenecks

“…[250] Here, AOPDF can also be used to precompensate both spectral phase and amplitude modulations. [223] In the amplifier, for a Ti:sapphire laser, ASE can be suppressed by optimizing the laser crystal, [251] the pump geometry, [252] the synchronization control, [253] the clean and strong injection, [254] the saturation absorption, [255] etc., and for an OPCPA laser, OPF can be suppressed by using a lowgain amplifier, [256] an extra quencher pulse, [257,258] a short-pulse (picosecond/femtosecond) pump, [26,259] a spatially chirped signal beam, [260,261] etc.…”

Numerical Investigation of Phase-Conjugate Wave Generation as a Pulse Cleaner in Femtosecond Petawatt Laser Systems

“…A number of techniques have been proposed and investigated experimentally over the past 20 years aiming to improve the temporal contrast of high peak power laser systems. These methods include the application of saturable absorbers [12], a nonlinear Sagnac interferometer [13], a double CPA scheme [14], nonlinear birefringence [15], cross-polarization wave generation (XPW) [16], a low-gain optical parametric amplification (OPA) [17], self-diffraction (SD) process [18], secondharmonic generation [19], spatial chirp technique [20], methods based on nonlinear Fourier-filter [21], rapid scanning Fabry-Perot (F-P) interferometer [22], plasma mirrors [23], and picosecondpumped OPCPA (PS-OPCPA) [24]. Among these, XPW, plasma mirrors, and PS-OPCPA are the most promising techniques, which have already been applied combined or independently in several petawatt-class laser facilities around the world [25]- [30].…”

In‐Band Noise Filtering via Spatio‐Spectral Coupling

“…As a result, current petawatt lasers typically achieve a pulse contrast of 10 9 , which degrades high‐field physics experiments . This situation creates the need for efficiently filtrating the in‐band noise . Unfortunately, in‐band filtering has not been resolved in optics owing to the dilemma of simultaneously attenuating noise and transmitting signal within a same spectral band.…”

“…[20][21][22] This situation creates the need for efficiently filtrating the in-band noise. [23] Unfortunately, in-band filtering has not been resolved in optics owing to the dilemma of simultaneously attenuating noise and transmitting signal within a same spectral band.…”