用于汤姆孙散射诊断的高重频高光束质量焦耳级Nd:YAG纳秒激光器  

High repetition rate and high beam quality joule level Nd:YAG nanosecond laser for Thomson scattering diagnosis

作　　者：邱基斯[1,2] 唐熊忻[1,2] 樊仲维[1] 陈艳中[1,2] 葛文琦[1,2] 王昊成[1] 刘昊[1] 

机构地区：[1]中国科学院光电研究院,北京100094 [2]中科和光(天津)应用激光技术研究所有限公司,天津300304

出　　处：《物理学报》2016年第15期97-103,共7页Acta Physica Sinica

基　　金：国家重大科研装备研制项目(批准号:ZDYZ2013-2);科技部创新人才推进计划重点领域创新团队(批准号:2014RA4051);中国科学院青年创新促进会资助的课题~~

摘　　要：基于激光二极管抽运棒状放大器和板条放大器相结合的方式,研制了一台应用于汤姆孙散射诊断的高重复频率、高光束质量焦耳级的Nd:YAG纳秒激光器.激光器采用主振荡功率放大的结构,主要包括单纵模种子、预放大单元和能量提取单元三部分.为了获得高光束质量的激光输出,采用相位共轭技术对激光光束畸变进行补偿.在重复频率200 Hz,单纵模种子注入单脉冲能量8.23μJ的条件下,获得了1.85)的能量输出.输出激光的脉冲宽度为5.36 ns,远场光斑为1.72倍衍射极限,能量稳定性(RMS)为1.3%.A joule-level Nd：YAG nanosecond laser of high repetition frequency and high beam quality is developed for Thom-son scattering diagnosis. The laser is designed as a master oscillator power-amplifier system mainly including single longitudinal mode seed, pre-amplifier unit and energy extraction unit. The single-longitudinal-mode Q-switched laser of a high stability is taken as the seed laser of output pulse at μJ level. The pre-amplifier unit amplifies the μJ-level pulse laser beam into hundreds of mJ level. In order to obtain the high-quality laser beam output, phase conjugation is adopted to compensate for the laser beam distortion. The ultra-filtered FC-770 is taken as an SBS gain medium of 0.0011 cm^-1 absorption coe？cient, 197.9 GW/cm^2 optical breakdown threshold and 3.5 cm/GW gain coe？cient. The double-pass amplification of SBS phase conjugation could realize a real-time repair towards the non-uniformity, deformation and wavefront aberration caused by thermal distortion of the optical components and the laser amplifier to achieve the uniform amplified beam output of high quality close to the diffraction limit. In the energy extraction unit, the amplifier of large-diameter slab is used for energy amplification. The size of the slab is 7 mm × 35 mm × 138.2 mm of 56？ cutting angle and 0.6% Nd^3＋ doping concentration. The slab is plated by a layer of SiO2 against light leak. Horizontal pumping mode is adopted. And the slow axis of the laser diode is almost the same as the length of the slat and the direction of laser transmission. The single-plane array is composed of 8 groups of vertical stacks and each group consists of 12 laser diode bars of power 200 W. At 200 Hz repetition frequency, 250 μs pump pulse width and 140 A pump current, the up to 2.3 J stored energy can be achieved The energy extraction unit achieves high gain amplification and finally outputs high-quality laser beam. Under the condition of 200 Hz high repetition frequency and 8.23 μJ single pulse energy injected by the single lon

关 键 词：二极管抽运 高重复频率 纳秒激光器 高光束质量 

分 类 号：TN248[电子电信—物理电子学]