Multi-stage harmonic cascade at seeded free-electron lasers  

作　　者：Li Zeng Yong Yu Xiaofan Wang Qinming Li Jitao Sun Xinmeng Li Zhigang He Jiayue Yang Guorong Wu Weiqing Zhang Xueming Yang 

机构地区：[1]Institute of Advanced Science Facilities,Shenzhen,China [2]Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian,China [3]University of Chinese Academy of Sciences,Beijing,China [4]College of Science,Southern University of Science and Technology,Shenzhen,China

出　　处：《High Power Laser Science and Engineering》2024年第6期197-206,共10页高功率激光科学与工程(英文版)

基　　金：support provided by the Dalian Coherent Light Source.This work was supported by the National Natural Science Foundation of China(Grant Nos.12305359 and 22288201);the Scientific Instrument Developing Project of Chinese Academy of Sciences(Grant No.GJJSTD20220001)

摘　　要：External seeded free-electron lasers(FELs) have exhibited substantial progress in diverse applications over the last decade. However, the frequency up-conversion efficiency in single-stage seeded FELs, particularly in high-gain harmonic generation(HGHG), remains constrained to a modest level. This limitation restricts its capability to conduct experiments within the ‘water window'. This paper presents a novel method for generating coherent X-ray FEL pulses in the water window region based on the HGHG scheme with multi-stage harmonic cascade. Without any additional modifications to the HGHG configuration, simulation results demonstrate the generation of intense 3 nm coherent FEL radiation using an external ultraviolet seed laser. This indicates an increase of the harmonic conversion number to approximately 90.A preliminary experiment is performed to evaluate the feasibility of this method. The proposed approach could potentially serve as an efficient method to broaden the wavelength coverage accessible to both existing and planned seeded X-ray FEL facilities.

关 键 词：free-electron laser harmonic lasing high-gain harmonic generation water window 

分 类 号：TN248[电子电信—物理电子学]