Optimization of temporal gate by two-color chirped lasers for the generation of isolated attosecond pulse in soft X rays  

作　　者：LIWEI HE GUANGLU YUAN KAN WANG WEIJIE HUA CHAO YU CHENG JIN 

机构地区：[1]Department of Applied Physics,Nanjing University of Science and Technology,Nanjing 210094,China [2]State Key Laboratory of Transient Optics and Photonics,Xi'an Institute of Optics and Precision Mechanics,Chinese Academy of Sciences,Xi'an 710119,China

出　　处：《Photonics Research》2019年第12期1407-1415,共9页光子学研究（英文版）

基　　金：National Natural Science Foundation of China(11774175,11704187,11774174,11834004)

摘　　要：We propose a simple and efficient method to optimize two-color chirped laser pulses by forming a"temporal gate"for the generation of isolated attosecond pulses(IAPs)in soft X rays.We show that the generation process for higher and cutoff harmonics can be effectively limited within the temporal gate,and the harmonic emission interval can be further reduced with the help of phase-matching by only selecting the contribution from shorttrajectory electrons.This two-color gating mechanism is verified by increasing the pulse duration,raising the gas pressure,and extending the target cutoff.Compared to the five-color waveform in Phys.Rev.Lett.102,063003(2009),our waveform can be used to generate the IAP in the long-duration laser pulse while the cutoff energy is higher without the reduction of harmonic yields.Our work provides an alternative temporal gating scheme for the generation of IAPs by simultaneously improving the harmonic conversion efficiency,thus making the attosecond soft X rays an intense and highly time-resolved tabletop light source for future applications.We propose a simple and efficient method to optimize two-color chirped laser pulses by forming a "temporal gate" for the generation of isolated attosecond pulses(IAPs) in soft X rays. We show that the generation process for higher and cutoff harmonics can be effectively limited within the temporal gate, and the harmonic emission interval can be further reduced with the help of phase-matching by only selecting the contribution from shorttrajectory electrons. This two-color gating mechanism is verified by increasing the pulse duration, raising the gas pressure, and extending the target cutoff. Compared to the five-color waveform in Phys. Rev. Lett. 102, 063003(2009), our waveform can be used to generate the IAP in the long-duration laser pulse while the cutoff energy is higher without the reduction of harmonic yields. Our work provides an alternative temporal gating scheme for the generation of IAPs by simultaneously improving the harmonic conversion efficiency, thus making the attosecond soft X rays an intense and highly time-resolved tabletop light source for future applications.

关 键 词：pulse HARMONIC SECOND 

分 类 号：O434.1[机械工程—光学工程] TN248[理学—光学]