基于双光成丝过程的光参量啁啾脉冲放大器前端  

Front-End of Optical Parametric Chirped-Pulse Amplifier Based on Dual Laser Filamentation

作　　者：冯天利 商景诚 李涛[1,2,3] Feng Tianli;Shang Jingcheng;Li Tao(School of Information Science and Engineering,Shandong University,Qingdao,Shandong 266237,China;Shandong Key Laboratory for Laser Technologies and Applications,Shandong University,Qingdao,Shandoyig 266237,China;Key Laboratory of Laser&Infrared System,Ministry of Education,Shandong University,Qingdao,Shandong 266237,China)

机构地区：[1]山东大学信息科学与工程学院,山东青岛266237 [2]山东大学山东省激光技术与应用重点实验室,山东青岛266237 [3]山东大学激光与红外系统集成技术教育部重点实验室,山东青岛266237

出　　处：《中国激光》2022年第7期136-142,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(62005144,61775119);山东省自然科学基金(ZR2020QF096,ZR2018MF033);山东省青年泰山学者基金(tsqn201812010);山东大学齐鲁青年项目;中德DAAD博士后基金。

摘　　要：报道了一种包含两个激光成丝过程的工作在2μm波段的光参量啁啾脉冲放大(OPCPA)系统前端,该前端工作在简并模式下,2μm种子激光脉冲通过近红外和可见光波段的超连续光谱之间差频产生。可见光和近红外波段的超连续光谱分别通过泵浦脉冲激光在两个YAG晶体中通过激光成丝过程产生。经过光参量放大及合理的色散补偿后,2μm种子激光脉冲的波长可从1830 nm覆盖至2320 nm,脉冲宽度为29 fs,单脉冲能量为16.7μJ,平均功率为167 m W,功率波动小于3%。Objective Gain narrowing and thermal effects that usually exist in a chirped-pulse amplifier can be avoided by anoptical parametric chirped-pulse amplifier(OPCPA),which relies on the optical parametric process existing in anonlinear crystal to realize pulse amplification.The 2μm OPCPA system is an ideal pumping source for waterwindow desktop X-ray light source,which has potential applications in medicine,biology,and material science.Thefront-end,which is the core of an OPCPA system,is unutilized to generate broadband and a few optical cycles seedlaser pulses.In this study,we propose a new scheme for 2μm OPCPA front-end based on dual laser filamentationprocesses.The proposed scheme can be used to realize 2μm laser seed pulses with broad spectrum,short pulseduration,and high-energy stability.Methods In the 2μm OPCPA front-end,Yb-doped laser amplifier with 500 fs pulse duration,100μJ pulse energy,and 10 k Hz pulse repetition rate is used as a pumping source.The output laser pulses are separated into two parts,which are respectively used to realize the visible and near-infrared(IR)supercontinuum generation(SCG)in YAG crystals through the dual laser filamentation processes and pump the OPA stages for amplifying 2μm seed laser pulse.Before the YAG crystal,a half-wave plate and a polarization beam splitter(PBS)are used to adjust the pulse energy incident into the YAG crystal.Then,another half-wave plate after the PBS is employed to adjust the polarization state of the incident pump laser.A CaF_(2) lens is used to adjust the beam spot size of the incident pump light on the YAG crystal.After SCG,the visible light and near-IR light are focused onto a Bi BO nonlinear crystal to generate the 2μm laser seed pulse using the difference frequency generation(DFG)process.The Bi BO nonlinear crystal is cut with a phase-matching angle of 10.7°for typeⅠphase matching in the DFG process.Results and Discussions The generated visible supercontinuum spectrum ranges from 500 to 850 nm,and the near-infrared(IR)supercontinuum spec

关 键 词：非线性光学 光参量啁啾脉冲放大器 激光成丝 2ΜM激光 差频产生 

分 类 号：O436[机械工程—光学工程]