侧面抽运(Tm,Ho):YLF晶体传导冷却百纳秒脉冲激光器  

Side-Pumped, Conductively Cooled (Tm, Ho)∶YLF Pulsed Laser with More than One-Hundred-Nanosecond Pulse Width

作　　者：蔡宇航 张俊旋 陈晓 宋铁强 刘继桥 陈卫标[1,2] 朱小磊[1,2] Cai Yuhang;Zhang Junxuan;Chen Xiao;Song Tieqiang;Liu Jiqiao;Chen Weibiao;Zhu Xiaolei(Key Laboratory of Space Laser Communication and Detection Technology,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Laboratory of Space Laser Engineering,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]中国科学院上海光学精密机械研究所空间激光传输与探测技术重点实验室,上海201800 [2]中国科学院大学材料与光电研究中心,北京100049 [3]中国科学院上海光学精密机械研究所航天激光工程研究室,上海201800

出　　处：《中国激光》2021年第13期54-60,共7页Chinese Journal of Lasers

基　　金：民用航天预先研究项目(D0403)。

摘　　要：针对基于航空和航天平台的激光雷达对2μm波段激光源的特殊需求,设计一种声光调Q、传导冷却(Tm,Ho)∶YLF晶体和波长为2051 nm的激光器。在4腔镜8字形环形谐振腔结构中,采用自主设计的侧面抽运楔形镜波导光学耦合系统实现均匀抽运(Tm,Ho)∶YLF晶体,从而实现高光束质量、百纳秒脉宽和2051 nm波长的调Q脉冲激光的稳定输出。当激光器的输出重复频率为1 Hz时,最高单脉冲能量达到141 mJ,脉冲宽度约为103 ns,此时光-光转换效率达到4.3%,实验测得光束质量因子在x和y方向上分别为1.22和1.08。Objective Owing to the advantages of being highly transmitted in the atmosphere, being safe to human eyes, being in the absorption spectrum band of water molecules, and being an efficient pump source for 3--5-μm laser, solid-state lasers emitting around 2 μm have been widely employed in many areas, including the medical field, high-precision ranging, environmental monitoring, and photoelectric counter-measurement. Laser source emitting at 2 μm with high energy and high beam quality output performance is a paramount component of the remote wind-measuring light radar. In addition, more than one hundred nanosecond pulse duration and narrow spectral linewidth are required. Therefore, the Q-switched 2-μm solid-state laser with a high energy output at room temperature has been a research hotspot for the space-borne lidar. Usually, the laser source used in the ground-based wind lidar system adopts the traditional liquid-cooling method, whereas those used in the air-or space-borne lidar system should adopt the conductive cooling design. To meet the special application requirement of the space-borne lidar, in this study, a laser diode(LD) side-pumped(Tm, Ho)∶YLF laser with a conductive cooling structure is developed by optimizing the key parameters of four-mirror ring cavity, such as the length of the cavity, the pump beam size inside the gain medium, output coupler mirror. As a result, high energy output with high energy efficiency and good beam quality are achieved.Methods The special eight-shaped ring cavity comprising two concave mirrors and two plane mirrors is designed(Fig.1).The pulse width of the Q-switched laser is calculated as a function of cavity length(Fig.2).To obtain a Q-switched pulse output of more than one hundred pulse width,the length of the ring cavity is chosen about 2580 mm.In theory,there are two waist positions inside the ring cavity,one placed with acousto-optic modulation(AOM)and another with(Tm,Ho)∶YLF crystal.In experiments,the driving signal waveform of the AOM is a square wave pulse

关 键 词：激光器 侧面抽运 (Tm Ho)∶YLF晶体 声光调Q 楔形镜耦合系统 

分 类 号：O436[机械工程—光学工程]