Development of a novel large bandwidth front-end system for high peak power OPCPA systems

Achieving 100 GW idler pulses from an existing petawatt optical parametric chirped pulse amplifier

Optical parametric chirped-pulse-amplification produces two broadband pulses, a signal and an idler, that can both provide peak powers >100 GW. In most cases the signal is used, but compressing the longer-wavelength idler opens up opportunities for experiments where the driving laser wavelength is a key parameter. This paper will describe several subsystems that were added to a petawatt class, Multi-Terawatt optical parametric amplifier line (MTW-OPAL) at the Laboratory for Laser Energetics to address two long-standing issues introduced by the use of the idler, angular dispersion, and spectral phase reversal. To the best of our knowledge, this is the first time that compensation of angular dispersion and phase reversal has been achieved in a single system and results in a 100 GW, 120-fs duration, pulse at 1170 nm.

Broad-bandwidth high-temporal-contrast carrier-envelope-phase-stabilized laser seed for 100 PW lasers

We demonstrate in this Letter the generation of carrier-envelope-phase (CEP)-stabilized laser pulses at 910 nm with simultaneously high-temporal-contrast, broad spectral bandwidths and few-cycle pulse durations. Through combining the techniques of cascaded optical parametric amplification (OPA) and second-harmonic generation (SHG) in the laser setup, a pulse temporal contrast as high as ${ \gt }{{10}^{12}}$>10¹² has been obtained at the laser output. During the OPA and SHG processes, both the pulse chirp and gain bandwidth are perfectly optimized, leading to the generation of 170 µJ pulses with ${ \gt }{200}\;{\rm nm}$>200nm bandwidth and ${\sim}{15}\;{\rm fs}$∼15fs pulse duration. Moreover, the CEP of the laser is stabilized passively to a noise level of less than 340 mrad. This high-quality pulsed light source, as the seed laser of the deuterated potassium dihydrogen phosphate (DKDP)-based 100 PW system, will be integrated into the Station of Extreme Light facility in the near future.

Output features of optical parametric chirped pulse amplification in LiB3O5 near 800 nm at different phase-matching geometries

We theoretically and experimentally investigated the output beam quality and wavefront distortion in four different phase-matching geometries in LBO-OPCPA at 800 nm: broadband noncollinear geometry, collinear geometry, pump-idler the Poynting vector collinear (S_p∥S_i) geometry, and pump-signal Poynting vector collinear (S_p∥S_s) geometry. It was found that the output profile is closely related to the noncollinear angle between Poynting vectors of parametric waves. However, the wavefront evolution depends mainly on the angles between the wave vectors. Broadband noncollinear geometry has the largest spatial modulation and wavefront distortion. Good output beam quality can be achieved in collinear geometry with little wavefront distortion, but the bandwidth is only approximately 10 nm. The S_p∥S_s and S_p∥S_i configurations result in a bandwidth of more than 20 nm with enhanced beam quality and small wavefront distortion. The two geometries have different output features wherein the former has a relatively lower modulation, and the latter shows smaller wavefront distortion.

Temperature- and wavelength-insensitive parametric amplification enabled by noncollinear achromatic phase-matching

Optical parametric chirped-pulse amplification (OPCPA) has been demonstrated to be a promising approach for pushing femtosecond pulses towards ultra-high peak powers. However, the future success of OPCPA strongly relies on the ability to manipulate its phase-matching (PM) configuration. When a high average power pump laser is involved, the thermal effects in nonlinear crystals induce phase-mismatch distortions that pose an inherent limitation on the conversion efficiency. Here, we demonstrate that the noncollinear configuration previously adopted for wavelength-insensitive PM can be employed for temperature-insensitive PM when the noncollinear angle is properly reset. Simultaneous temperature- and wavelength-insensitive PM is realized for the first time by imposing such a temperature-insensitive noncollinear configuration with an angularly dispersed seed signal. Based on the lithium triborate crystal, the proposed noncollinear achromatic PM has a thermal acceptance 6 times larger than that of the conventional wavelength-insensitive noncollinear PM and has a sufficient spectral acceptance to support pulse durations of ~20 fs at 800 nm. These achievements open new possibilities for generating ultra-high peak power lasers with high average power.