基于单通单光栅对主压缩器的多步脉冲压缩器

Asymmetric four-grating compressor for ultrafast high power lasers

The peak power improvement and running safety of petawatt (PW) lasers are limited by laser-induced damage of optical components with limited sizes and damage thresholds. Diffraction gratings in pulse compressors have been the shortest stave of PW lasers up to now, as to manufacture a high quality meter-sized grating remains particularly challenging. Here, the asymmetric four-grating compressor (AFGC) with asymmetric configuration is proposed for PW lasers to increase the maximum bearable output pulse energy and running safety without neither additional optical component nor extra control in co…

Compact optical grating compressor

A novel design of a grating-based optical pulse compressor is proposed. The proposed compressor provides a large group delay dispersion while keeping the compressor linear size small. The design of the proposed compressor is based on a traditional Treacy compressor with a straightforward modification of inserting two lenses between the compressor's gratings. This simple alternation aims to substantially increase group delay dispersion of the compressor or alternatively to decrease the compressor size while maintaining its group delay dispersion. A theoretical description of the enhanced compre…

降低对称和非对称压缩器中的激光束通量与强度波动

Reducing laser beam fluence and intensity fluctuations in symmetric and asymmetric compressors

本文解析研究了非对称双光栅对压缩器中的时空耦合效应，发现其不改变远场通量，但通过空间噪声滞后或超前降低通量波动，并给出了仅依赖一个参数的波动谱与均方根表达式及自聚焦抑制效率。

Frequency-domain "single-shot" (FDSS) transient absorption spectroscopy using a variable-length grating pair compressor

Single-shot ultrafast spectroscopy based on the frequency encoding of transient absorbance kinetics (FDSS) is demonstrated. These kinetics are sampled spectrally using linearly chirped pulses derived from a Ti:sapphire laser. A variable length grating pair compressor is used to provide group velocity dispersion out to -1.6 ps^2 and achieve the sampling of 512 channels per a 2-to-160 ps window with sensitivity > 5e-4. The possibilities of FDSS are illustrated with studies of three photon ionization of liquid water and one-photon excitation of a thin-film

Low-dispersion low-loss dielectric gratings for efficient ultrafast laser pulse compression at high average powers

We have developed low-dispersion (1480 l/mm), resonance-free, diffraction gratings made of dielectric materials resistant to femtosecond laser damage $(SiO_{2}/HfO_{2})$. A 14 cm diameter sample was fabricated resulting in a mean diffraction efficiency of 99.1% at λ = 810 nm with 0.4% uniformity using equipment which can fabricate gratings up to 1m diagonal. The implementation of these gratings in the compression of 30 fs pulses in an out-of-plane geometry can result in compressor efficiencies of ~95%. The measured laser absorption is 500x lower than current ultrafast petawatt-class compressor…

Compensation of nonlinear phase shifts with third-order dispersion: fiber stretchers can out-perform grating stretchers in short-pulse fiber amplifiers

We show that nonlinear phase shifts and third-order dispersion can compensate each other in short-pulse fiber amplifiers. In particular, we consider chirped-pulse fiber amplifiers at wavelengths for which the fiber dispersion is normal. The nonlinear phase shift accumulated in the amplifier can be compensated by the third-order dispersion of the combination of a fiber stretcher and grating compressor. A numerical model is used to predict the compensation, and initial experimental results that exhibit the main features of the calculations are presented. In the presence of third-order dispersion…

等离子体衍射光栅的色散特性：迈向基于等离子体的激光脉冲压缩

Dispersive Properties of Plasma Diffraction Gratings: Towards Plasma-Based Laser Pulse Compression

研究通过实验测量等离子体传输光栅的角色散、角带宽和衍射角，证实其色散和衍射特性与光学理论一致，为等离子体光栅压缩器设计提供可能方案，指向皮瓦至艾瓦峰值功率紧凑激光器的发展路径。

2.6mJ/100Hz CEP stable near-single-cycle 4μm laser based on OPCPA and hollow-core-fiber compression

A carrier envelope phase stable near-single cycle mid-infrared laser based on optical parametric chirped pulse amplification and hollow-core-fiber compression is demonstrated. 4 μm laser pulses with 11.8 mJ energy are delivered from a KTA based OPCPA with 100 Hz repetition rate, and compressed to be ~105 fs by a two-grating compressor with efficiency over 50%. Subsequently, the pulse spectrum is broadened by employing a krypton gas-filled hollow-core-fiber (HCF). Then, the pulse duration is further compressed to 21.5 fs through a CaF2 bulk material with energy of 2.6 mJ and stability of 0.9% R…

啁啾脉冲波导放大器

Chirped pulse waveguide amplifier

本文提出一种单模Cr:ZnS晶体波导超快放大器，利用超快激光写入的凹陷包层波导实现5.5 dB/cm增益和2.35 W平均输出功率，并通过解析模型优化设计，在CPA装置中验证了宽带高增益放大性能。

Frequency-domain "single-shot" (FDSS) ultrafast transient absorption spectroscopy using compressed laser pulses. Part I. Basic treatment

Single-shot ultrafast absorbance spectroscopy based on the frequency encoding of the kinetics is analyzed theoretically and implemented experimentally. The kinetics are sampled in the frequency domain using linearly chirped, amplified 33 fs FWHM pulses derived from a Ti:sapphire laser. A variable length grating pair compressor is used to achieve the time resolution of 500-1000 channels per a 2-to-160 ps window with sensitivity > 5x10-4. In terms of the acquisition time, FDSS has an advantage over the pump-probe spectroscopy in a situation when the "noise" is dominated by amplitude variations o…