• High Power Laser Science and Engineering
  • Vol. 10, Issue 3, 03000e20 (2022)
Yirui Wang1, Jing Wang1、*, Jingui Ma1, Peng Yuan1, and Liejia Qian1、2
Author Affiliations
  • 1School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai200240, China
  • 2Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai200240, China
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    DOI: 10.1017/hpl.2022.10 Cite this Article
    Yirui Wang, Jing Wang, Jingui Ma, Peng Yuan, Liejia Qian. Numerical study of spatial chirp distortion in quasi-parametric chirped-pulse amplification[J]. High Power Laser Science and Engineering, 2022, 10(3): 03000e20 Copy Citation Text show less

    Abstract

    Optical parametric chirped-pulse amplification is inevitably subject to high-order spatial chirp, particularly under the condition of saturated amplification and a Gaussian pump; this corresponds to an irreversible spatiotemporal distortion and consequently degrades the maximum attainable focused intensity. In this paper, we reveal that such spatial chirp distortion can be significantly mitigated in quasi-parametric chirped-pulse amplification (QPCPA) with idler absorption. Simulation results show that the quality of focused intensity in saturated QPCPA is nearly ideal, with a spatiotemporal Strehl ratio higher than 0.98. As the seed bandwidth increases, the idler absorption spectrum may not be uniform, but the Strehl ratio in QPCPA can be still high enough due to stronger idler absorption.

    1 Introduction

    Ultrashort ultra-intense laser pulses have delivered peak intensities of 1022–1023 W/cm2 that represents the strongest radiation in the laboratory and enables the experimental research of extreme high-field physics[13]. However, ultrashort pulses with broad bandwidths are prone to spatiotemporal couplings (STCs)[47]. That is, there exists an interdependence between the temporal (or spectral) and spatial (or angular) properties of electromagnetic fields[8]. One of the simplest first-order STCs in space and time has a mathematical description of E(x, t + ξx) where ξ is the linear coupling coefficient. Since first-order STCs can be produced and compensated through angular-dispersion devices, they have been widely used to construct a pulse stretcher and compressor for chirped-pulse amplification (CPA)[916]. For example, in a pulse stretcher consisting of four prisms, the angular dispersion induced by the first prism is completely compensated in the second prism, which is anti-parallel to the first one, resulting in laser pulses with a pure temporal chirp at the output[11]. However, it is non-trivial to compensate all the STCs introduced during the pulse propagation and amplification. For example, the misalignment of the gratings in either the stretcher or compressor results in residual couplings (also termed spatiotemporal distortions), including both first-order STCs and complicated high-order STCs. It has been experimentally demonstrated that the high-order STCs in imperfect compression are very difficult to be compensated and contribute to most of the spatiotemporal distortions of the compressed and focused signal[12,1721].

    Copy Citation Text
    Yirui Wang, Jing Wang, Jingui Ma, Peng Yuan, Liejia Qian. Numerical study of spatial chirp distortion in quasi-parametric chirped-pulse amplification[J]. High Power Laser Science and Engineering, 2022, 10(3): 03000e20
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