为了改善被动调Q激光器输出不稳定的现象, 利用Nd:YVO4具有增益方向性的特点, 使用电光晶体将线偏振光光矢量方向旋转90°, 实现腔内增益突变, 进而实现被动调Q稳定输出。利用该方法, 在LD连续泵浦Nd:YVO4被动调Q实验中, 当耦合输出镜反射率为80%, 饱和吸收体初始透射率为83.06%, 泵浦功率为22 W时, 输出功率为4.68 W, 调Q序列脉冲的重复频率为49.16 kHz, 脉冲宽度为26.28 ns。并且在泵浦功率从10~22 W的情况下, 获得了稳定的被动调Q激光输出。脉冲幅度波动性低于±2.4%, 脉冲时间波动性低于±5%, 重复频率的不稳定性低于1%, 光光转换效率斜效率达到21.27%, 斜效率为34%。

In order to improve the stability of the passively Q-switched pulses, the gain orientation of the Nd:YVO4 was taken advantage and an electro-optic crystal was used to rotate the line polarized light vector by 90°, then the intracavity gain mutation can be realized, thereby stable output of the passively Q-switched was realized. Through this method, when the reflectivity of the coupling output mirror was 80% and the initial transmittance of the saturated absorber was 83.06%, the output power reached 4.68 W at a given pump power of 22 W, high repetition rate output with repetition frequency of 49.16 kHz and the pulse width of 26.28 ns was obtained in the experiment of LD continuously pumped Nd:YVO4 passively Q-switched. In the case of the pump current from 10 W to 22 W, a stable passive Q laser output was obtained. The pulse-to-pulse amplitude fluctuation was less than ±2.4%. The inter-pulse timing jitter of the Q-switched pulse train was found to be less than ±5%. The instability of repetition rate was less than 1%. For a slope efficiency of 34%, the corresponding optical-to-optical conversion efficiency reached 21.27%.