In-situ measurement and compensation of complex spatio-temporal couplings in ultra-intense lasers. (January 2023)

• Record Type: Journal Article
• Authors: Zang, Zhongming; Peng, Shaojing; Jin, Wangzan; Zuo, Yanlei; Steinmeyer, Günter; Dai, Yaping; Liu, Dong
• Is Part Of: Optics and lasers in engineering. Volume 160(2023)
• Publication Date: 2023-01
• Subjects: Ultra-intense laser -- Spatio-temporal coupling -- Grating compressor -- In-situ measurement -- Wavefront error -- Continuous phase plate; G1/G2/G3/G4 first/second/third/fourth grating of the four grating Treacy compressor -- STC spatio-temporal coupling -- CSTC complex spatio-temporal coupling -- CPP continuous phase plate -- RMS root mean square -- CPA Chirped-pulse amplification -- OPCPA optical parametric Chirped-pulse amplification -- SHWS Shark-Hartmann wavefront sensor -- LSI lateral shearing interferometry -- PLSI pseudo lateral shearing interferometry -- CCD charge-coupled device -- FOV field of view -- PV peak-valley -- MHSF mid- and high-spatial frequency -- FWHM full width at half maxima -- SSR square sum root; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2022.107239
• Languages: English
• ISSNs: 0143-8166

Abstract

Highlights: In-situ measurement method for CSTC wavefront error of Treacy compressors. Tunable measurement laser is generated by the stretcher with a slit. Systematic errors and the impact of other optics are eliminated in measurements. Spatio-temporal couplings are effectively reduced with a continuous phase plate. Ultra-intense laser facilities require no changes using the proposed method. Abstract: Diffraction wavefront errors of large-scale Treacy compressors may induce complex spatio-temporal couplings (CSTCs) in chirped pulse amplification and degrade the quality of the pulsed beam in both near and far fields. This problem is particularly pronounced in petawatt laser facilities that require tiled compressor gratings. Here, to the best of our knowledge, we present the first in-situ measurement method named pseudo lateral shearing interferometry (PLSI) for the CSTC wavefront error and manufacture a continuous phase plate (CPP) according to the measurement to reduce the distortion. A Shark-Hartmann wavefront sensor is used to characterize wavefronts of the entire system at two different wavelengths, and the CSTC wavefront error can be reconstructed similarly to lateral shearing interferometry (LSI). Our approach strongly reduces systematic errors and the impact of other optics. The root-mean-square (RMS) value of the resulting error is 40 nm in a single measurement, and the day-to-day repeatability is 55 nm. The employed CPP reduces the peak-to-valley (PV) value of the CSTC wavefront error from 675 to 312 nm, and the focused peak intensity is improved by 51%.