高重复频率、窄脉冲声光调Q射频波导CO_(2)激光器  

Acousto-Optic Q-Switched Radio Frequency Waveguide CO_(2) Laser with High Repetition Rate and Short Pulse Width

作　　者：吴名俊 谭荣清 李辉 宁方晋 郑义军 朱子任 白进周 Wu Mingjun;Tan Rongqing;Li Hui;Ning Fangjin;Zheng Yijun;Zhu Ziren;Bai Jinzhou(The Laser Engineering&Technology Research Center,Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China;School of Electronic,Electrical and Communication Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院空天信息创新研究院激光工程技术研究中心,北京100094 [2]中国科学院大学电子电气与通信工程学院,北京100049

出　　处：《中国激光》2023年第22期47-54,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(61775215);中国科学院科研仪器设备研制项目(YJKYYQ20190041)。

摘　　要：为实现高重复频率、窄脉冲激光输出,研制了一台声光调Q射频波导CO_(2)激光器。首先,采用矩形波导耦合损耗理论分析了波导耦合效率与全反镜曲率半径、全反镜到波导口距离的关系,获得了波导耦合损耗较小时的优化参数。其次,研究了工作气压与激光输出的关系,以及脉冲拖尾长度与Q开关开启时间的关系。当工作气压为6.5 kPa,Q开关开启时间为0.6μs时,获得了无拖尾脉冲波形,并分析了峰值功率、平均功率、脉宽等参数随重复频率的变化规律。设计的激光器可实现重复频率1 Hz~100 kHz可调。当Q开关开启时间为0.6μs、重复频率为1 kHz时,获得的脉冲宽度为108.2 ns,峰值功率为2809.6 W;当重复频率为100 kHz时,脉宽为135.1 ns,峰值功率为257 W。当重复频率为70 kHz时,测得x和y方向上的光束质量因子分别为1.50和1.21。Objective High-repetition-rate,short-pulse CO_(2) lasers have broad application prospects in non-metal processing,laser medicine,extreme ultraviolet(EUV)lithography,photoelectric countermeasures,and other fields.Radiofrequency(RF)-excited waveguide CO_(2) lasers are small,have high efficiency and long life,and are maintenance-free;thus,continuous-wave output CO_(2) lasers have been widely used.The main technical means for RF-excited waveguide CO_(2) lasers to achieve high peak power pulse outputs include electrooptical Q-switching,mechanical Q-switching,and acousto-optic Q-switching.Electro-optical Q-switching can achieve pulsed laser output with repetition rates of more than 100 kHz and pulse widths of tens of nanoseconds;however,electro-optical crystals,such as CdTe,are difficult to grow,easy to damage,and expensive,and the driving voltage required by the crystals is more than 1 kV;thus,the technology is relatively complex.The structure of mechanical Q-switching is simple and the cost is low;however,it is limited by the speed of the motor and the stability of the chopper at high speed.It is difficult to obtain a stable pulse output with a high repetition rate,and it is difficult to accurately control and encode the pulse.Acousto-optic Q-switching is normally realized by placing an acousto-optic modulator in the resonant cavity,and the loss in the cavity is modulated by acousto-optic diffraction to achieve a Qswitched pulse output,which has a low device cost and a high damage threshold.Acousto-optic Q-switched RF waveguide CO_(2) lasers can achieve pulse output with high repetition rate and short pulse width.They have a compact structure and are easy to carry,thus providing high-quality laser sources for photoelectric countermeasures and other fields.Methods The laser designed in this study adopts a semi-external cavity structure.An acousto-optic modulator is placed between the total reflection mirror and the window,and intracavity loss modulation is realized by the acousto-optic diffraction effect.Using rectang

关 键 词：激光器 波导CO_(2)激光器 高重复频率 窄脉冲宽度 声光调Q 

分 类 号：TN248.2[电子电信—物理电子学]