双晶电光Q开关消光比的研究  

Research on Extinction Ratio of Double-Crystal Electro-Optic Q-switch

作　　者：商继芳 李清连[2] 孙兴 陈铃 杜文静 李留帮 Shang Jifang;Li Qinglian;Sun Xing;Chen Ling;Du Wenjing;Li Liubang(Henan Key Laboratory of Electronic Ceramic Materials and Application,College of Materials Engineering,Henan University of Engineering,Zhengzhou 451191,Henan,China;School of Physics,Nankai University,Tianjin 300071,China;Zhengzhou Zhuoertai New Material Technology Co.,Ltd.,Zhengzhou 450016,Henan,China)

机构地区：[1]河南工程学院材料工程学院河南省电子陶瓷材料与应用重点实验室,河南郑州451191 [2]南开大学物理科学学院,天津300071 [3]郑州卓而泰新材料科技有限公司,河南郑州450016

出　　处：《中国激光》2024年第8期7-15,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(51902087,52202618);河南省科技攻关项目(232102210168);天津市自然科学基金青年项目(S22QND945);河南省青年人才托举工程项目(2021HYTP004);河南工程学院横向课题(HKJ2023079)。

摘　　要：双晶匹配电光Q开关能够利用晶体的最大有效电光系数,大幅降低半波电压,具有重要的应用价值,但其消光比易受多种因素的制约。系统分析了影响双晶电光Q开关消光比的各个因素,建立了包含光学不均匀性、晶向偏离、两晶体温度变化、长度偏差及温差等参数的系列相位延迟公式,由此分析计算了各因素的容差范围。结果表明:光学不均匀性、两晶体的长度偏差和温差是影响消光比的关键因素;当仅考虑单一变量时,消光比与此变量的平方成反比;同时,晶体长度对消光比也有显著影响,当光学不均匀性、晶向偏离、温差一定时,消光比与晶体长度的平方成反比。制备了两种不同尺寸的双晶钽酸锂电光Q开关,实验证实长度较短的Q开关的双晶匹配质量更好,消光比更高,其消光比主要受光学不均匀性的限制。研究结果可为高消光比双晶电光Q开关的研制提供重要指导。Objective Electro-optic(EO)Q-switching technology has been extensively used to fabricate pulsed lasers.Its advantages of a faster switching rate,better hold-off ability,and controllable repetition rates enable the generation of energetic short laser pulses.To date,practical EO crystals include LiNbO3(LN),LiTaO3(LT),KD2PO4(DKDP),and RbTiOPO4(RTP).To achieve a low driving voltage,the laser must propagate along the non-optical-axis direction of these crystals,which introduces additional phase retardation induced by natural birefringence.Using a second crystal that is rotated 90°with respect to the first crystal is necessary to compensate for the natural birefringence and its strong thermal fluctuations.However,achieving double-crystal EO Q-switches with a high extinction ratio is difficult because both crystals should have high transverse optical homogeneity and should be carefully matched.The matching quality may be affected by numerous factors,including the optical inhomogeneity of the crystals,optical processing accuracy,and temperature changes.To date,factors affecting the extinction ratio of double-crystal EO Q-switches have not been systematically studied,limiting the development and application of double-crystal EO Q-switches.In this study,we comprehensively analyze the factors affecting the extinction ratio and fabricated double-crystal LT EO Q-switches.Methods First,using double-crystal LT EO Q-switches as examples,we analyze the factors that affect the extinction ratio of double-crystal EO Q-switches.To maximize the EO effect,an LT Q-switch is fabricated from two x-cut LT crystals with light propagating along the x axis and voltage applied along the z axis.A set of analytical phase-shift formulas that consider the optical inhomogeneity,crystallographic orientation deviation,length deviation,and temperature change of the two matching crystals are derived.Combined with the transmittance formula for the parallel-polarization system,the tolerances of these factors are calculated using an extinction ratio of 1

关 键 词：激光光学 光开关器件 电光调Q 双晶匹配 消光比 钽酸锂晶体 

分 类 号：O734[理学—晶体学]