被动调Q双腔双频Nd:YAG激光器设计及实验  

Design and Experimental Investigation of Passively Q-Switched Two-Cavity Dual-Frequency Nd:YAG Laser

作　　者：周叶 焦明星[1] 连天虹[1] 邢俊红[1] 刘芸[1] 刘健宁[1] Zhou Ye;Jiao Mingxing;Lian Tianhong;Xing Junhong;Liu Yun;Liu Jianning(School of Mechanical and Precision Instrument Engineering,Xi'an University of Technology, Xi’an,Shaanxi 710048,China)

机构地区：[1]西安理工大学机械与精密仪器工程学院,陕西西安710048

出　　处：《中国激光》2018年第12期48-55,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(61605156);陕西省科技厅自然科学基础研究计划(2016JQ6073)

摘　　要：为了获得峰值功率高、相干性好、频差大的双频脉冲激光,设计了一种二极管端面抽运被动调Q双腔双频Nd:YAG激光器,该激光器采用共增益T型双驻波腔结构,腔内偏振分光棱镜和半波片组成的双折射滤光片作为激光纵模选择元件,并以Cr4+:YAG晶体作为腔内被动Q开关,使1064nm激光的p分量和s分量分别在直线腔和直角腔内同时以单纵模振荡,从而获得1064nm正交线偏振双频激光脉冲输出。建立了被动调Q双腔Nd:YAG激光器速率方程组,理论分析了双腔脉冲激光输出特性,实验研究了双腔双频脉冲激光的振荡特性和输出特性。实验结果表明:当激光二极管的抽运功率为2.7W时,从直线腔输出的p偏振单频脉冲激光的重复频率、脉冲宽度和峰值功率依次为5.8kHz、42ns和126.4W;从直角腔输出的s偏振单纵模激光脉冲的重复频率、脉冲宽度和峰值功率依次为5.8kHz、40ns和133.6 W。该双频脉冲激光的频差约为10GHz。这种双频脉冲固体激光器在激光干涉测量和相干激光雷达探测等领域具有广阔的应用前景。In order to obtain a dual frequency pulsed laser with high peak power, good coherence and large frequency difference, a diode-pumped passively Q-switched two-cavity dual-frequency Nd∶YAG laser is designed, which adopts a structure composed of two T-shaped standing-wave cavities sharing a common gain medium. An intracavity polarizing beam-splitter and a half wave-plate are combined to form a birefringent filter acting as the laser longitudinal mode selector, a piece of Cr4+∶YAG crystal is chosen as a passive Q-switch, and thus the p-component and s-component of this 1064 nm laser are forced to oscillate simultaneously in a single longitudinal mode within the linear and right angle cavities, respectively. The output of orthogonally and linearly polarized dual-frequency pulsed laser at 1064 nm is realized. In addition, the rate equation group of a passively Q-switched two-cavity Nd∶YAG laser is established and the output characteristics of two-cavity pulsed laser are analyzed theoretically. Moreover, both the oscillation and output characteristics of this two-cavity dual-frequency pulsed laser are investigated experimentally. The experimental results show that, when the pump power of laser diode is 2.7 W, as for the p-polarization single-frequency pulsed laser output from the linear cavity, the repetition frequency, pulse width and peak power are 5.8 kHz, 42 ns and 126.4 W, respectively. In contrast, as for the s-polarization single-frequency pulsed laser output from the right angle cavity, those are 5.8 kHz, 40 ns and 133.6 W, respectively. The frequency-difference of this dual-frequency pulsed laser is approximately 10 GHz. This dual-frequency pulsed solid-state laser has a wide application prospect in the fields of laser interferometry, lidar coherent detection, and so on.

关 键 词：激光器 双频脉冲激光 双折射滤光片 被动调Q CR^4+:YAG晶体 

分 类 号：TN242[电子电信—物理电子学]