基于气体高次谐波的高亮度超快相干极紫外光源的研发  

Development of High-Photon-Flux Ultrafast Coherent Extreme-Ultraviolet Light Source Based on Gas High Harmonic Generation

作　　者：姚嘉泰 刘嘉月 杜进旭 周聪 邱子歌 邓瀚燊 肖震宇 刘亦婷 彭雅珮 刘小亮 李小勇 王国利[2] 王朋飞 周效信[2] 吴思忠 李露 周沧涛 Yao Jiatai;Liu Jiayue;Du Jinxu;Zhou Cong;Qiu Zige;Deng Hanshen;Xiao Zhenyu;Liu Yiting;Peng Yapei;Liu Xiaoliang;Li Xiaoyong;Wang Guoli;Wang Pengfei;Zhou Xiaoxin;Wu Sizhong;Li Lu;Zhou Cangtao(Shenzhen Key Laboratory of Ultra-Intense Laser and Advanced Material Technology,College of Engineering Physics,Shenzhen Technology University,Shenzhen 518118,Guangdong,China;College of Physics and Electronic Engineering,Northwest Normal University,Lanzhou 730070,Gansu,China;School of Nuclear Science and Engineering,East China University of Technology,Nanchang 330013,Jiangxi,China;College of Electrical Engineering,Northwest Minzu University,Lanzhou 730030,Gansu,China;Shanghai Y-LASER Technology Co.,Ltd.,Shanghai 201800,China)

机构地区：[1]深圳技术大学工程物理学院深圳市超强激光与先进材料技术重点实验室,广东深圳518118 [2]西北师范大学物理与电子工程学院,甘肃兰州730070 [3]东华理工大学核科学与工程学院,江西南昌330013 [4]西北民族大学电气工程学院,甘肃兰州730030 [5]上海镱镭飞秒激光技术有限公司,上海201800

出　　处：《中国激光》2024年第19期246-257,共12页Chinese Journal of Lasers

基　　金：国家自然科学基金(U2330128,12205203);国家重点研发计划(2022YFA1603200,2022YFA1603202)。

摘　　要：高平均功率、高峰值功率是超快激光技术发展的重要趋势,也是拓展其应用范围的关键。利用超高重复频率光纤激光器,开发了两套腔外脉冲再压缩模块,通过气体高次谐波技术,获得了高亮度超快相干极紫外光源。结合三维强场近似理论模型,分别从实验和理论上对驱动脉冲能量和脉冲宽度、气体种类、气体压强以及Z方向上的光场耦合情况等重要相位匹配条件进行了系统的研究。在500 kHz重复频率的驱动下,获得了高亮度的21~40 nm高次谐波信号,各阶次谐波信号的光子数通量均超过1.6×10^(10)photon/s,最强阶次谐波为第35阶谐波(29.4 nm),其光子数通量为1.8×10^(12)photon/s,能量转换效率为5×10^(-7)。基于该实验线路,进一步优化驱动脉冲宽度和脉冲能量,并结合毛细管气体单元,可实现更短波长(约为10 nm)的高亮度超快相干极紫外光源,为纳米结构成像、原子分子和新型材料表面超快动力学过程、极紫外波段光学元器件损伤和性能测试等提供综合实验平台。Objective High average and peak powers are key technical indicators for the development of ultrafast laser technology,enabling a wide range of applications.With the rapid growth of ultrafast laser technologies,high-average-power lasers with ultrahigh repetition rates in the order of MHz have gained attention as fascinating secondary sources,such as the laser-like desktop source of high-order harmonic generation(HHG)in the extreme ultraviolet(XUV)regime with ultrahigh repetition rate,which has great potential in coherent diffraction imaging,coincidence detection,photoelectron spectroscopy,XUV optics metrology,and ultrafast atomic and molecular physics and chemistry.This is because of its excellent coherence,short wavelength,and femtosecond-to-attosecond pulse duration,making it an excellent supplementary source for synchrotron and free-electron lasers.However,high-average-power laser technologies with ultrahigh repetition rates are limited to pulse duration of hundreds of femtoseconds to a few picoseconds,which obstructs gas HHG.In this study,two different post-compression modules are developed to optimize HHG driving pulses.Sufficient driving conditions related to phase matching are comprehensively studied.Methods High-photon-flux coherent XUV sources are developed using a fiber laser with an ultrahigh repetition rate.In the experiment,two nonlinear post-compression systems are investigated:an argon-filled hollow-core fiber(HCF,Fig.1)and a multi-pass cell(MPC,Fig.2)filled with argon.Both approaches successfully broaden the laser spectrum and further reduce the pulse duration from 230 fs to below 40 fs after proper dispersion compensation with chirped mirrors.The ytterbium-doped fiber laser with a center wavelength of 1030 nm provides a maximum average power of 80 W with a pulse duration of 230 fs and supports flexible pulse repetition rates from 50 kHz to 19 MHz.The maximum pulse energy(400μJ)is assigned at 200 kHz.As depicted in Fig.4,the post-compressed pulses are subsequently focused by a gold-coated spherica

关 键 词：高次谐波 极紫外光源 空芯光纤脉冲压缩 多通道单元脉冲再压缩 

分 类 号：O436[机械工程—光学工程]