种子注入固体激光相干探测实验研究

Injection Seeding Nd∶YAG Laser and Its Application in Heterodyne Detection

利用激光二极管(LD)抽运的单块非平面单向行波环形腔单频固体激光器作为种子源,对电光调Q的功率激光器进行种子注入。通过温度反馈控制对种子光源进行频率调节,控制种子光源和从动激光器自由振荡频率的匹配,得到种子注入发生比率为80%,脉冲功率半宽度为20 ns,能量为5 mJ,重复频率为500 Hz的单频激光输出。利用目标反射回波与声光移频的本振光进行外差探测,获得了包含速度信息的相干信号输出。

A high peak-power single-longitudinal mode （SLM） Q-switched laser which seeding injected by a laser diode （LD） pumped continuous-wave monolithic single-frequency unidirectional non-planar ring oscillator （NPRO） is investigated. The frequency of the NPRO master laser is adjusted by precisely controlling the temperature of the laser crystal to match the frequency of Q-switching slave laser. SLM output of slave laser with 5 mJ energy and 20 ns pulse duration is achieved at the 500 Hz repetitive frequency. The ratio of the seeding injected probability is 80%. Part of single-frequency beam from the master laser is frequency shifted by an acoustooptical modulator （AOM） used as the local oscillating laser in the heterodyne system in order to execute heterodyne detection with the Q-switched laser backscattered by a rotating object, then the velocity information heterodyne signal is obtained.