铌酸锂晶体低温电光调Q性能的影响因素研究  

Factors Affecting Cold-Temperature Electro-Optic Q-Switching Performance of Lithium Niobate Crystals

作　　者：商继芳 李清连[2] 陆泽洋 孙兴 陈铃 杜文静 李留帮 Shang Jifang;Li Qinglian;Lu Zeyang;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19期258-266,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(242102211083,232102210168);天津市自然科学基金青年项目(S22QND945);河南工程学院横向课题(HKJ2023079)。

摘　　要：对铌酸锂(LN)电光Q开关低温性能大幅降低且原因不明的问题进行了系统研究。提出并搭建了高低温锥光干涉测量装置,通过检测多块晶体的低温光学均匀性,发现低温下LN晶体通光口径内不同区域的双折射特性发生了不同变化,但分布具有规律性,各晶体双折射特性变化的程度不同,与低温调Q输出相吻合。结合低温下可能影响双折射特性的各因素进行了分析,模拟了晶体中热释电电场的分布,发现由该电场引起的锥光干涉图样的变化及其分布规律与低温锥光干涉测量结果一致,由此探明热释电电场是影响低温调Q性能的主要因素,其与热释电系数和电导率有关。对LN晶体进行热化学还原处理,使其电导率提高约4.9倍,实验证实其低温光学均匀性得到明显改善,低温调Q性能得到显著提高,在-30℃以上时动静比可达常温时的90%以上,-40℃时动静比为常温时的80%。研究结果对高温度稳定性LN电光Q开关的研制具有重要指导意义。Objective Lithium niobate(LiNbO3,LN)is currently the preferred electro-optic(EO)Q-switch material for military lasers owing to its ease of growth and processing,low cost,and nonhygroscopic nature.Major national projects such as aerospace projects,lunar exploration,and Beidou satellite navigation demand lasers that can operate over a wide temperature range.However,the performance of LN EO Q switches deteriorates considerably at subfreezing temperatures.Currently,researchers attribute the unsatisfactory performance of cold Q-switching to three reasons:stress birefringence,the pyroelectric effect,and the thermo-optic effect.Most related studies focus on improving cold performance,whereas studies that investigate the mechanism underlying degraded cold Qswitching performance are few.Consequently,the reasons for unsatisfactory cold Q-switching performance are contradictory and confusing,which limits the development of LN EO Q switches with high-temperature stability.In this study,we perform comprehensive investigations to determine the primary factors affecting cold Q-switching performance and fabricate LN Q switches with improved temperature stability.Methods First,the cold Q-switching performance of several LN Q switches is measured using a flash-lamp pumped Nd∶YAG laser,which is placed in a high‒low temperature test chamber.The optical homogeneity of these Q switches at cold temperatures is characterized using high‒low-temperature conoscopic interference technology,from which the variation in the birefringence at cold temperatures is clearly observed.Subsequently,we analyze the various factors that may affect the birefringence at cold temperatures and their influence characteristics.The distribution of the electric field created by pyroelectric charges inside the LN crystal is simulated using finite-element-analysis software.Combining the above with the EO effect of the LN crystals,we analyze the spatial-distribution characteristics of birefringence induced by the pyroelectric field and compare them with the e

关 键 词：光开关器件 电光调Q 铌酸锂晶体 低温调Q性能 热释电效应 

分 类 号：O734[理学—晶体学]