以腔内倍频调Q激光器工作原理为基础，研究了多种形式抽运光分布的情况下倍频光的脉冲形状以及脉冲持续过程中光场分布的时间不稳定性，分析了倍频光光束质量随时间的变化规律。发现腔内倍频调Q激光器输出的倍频光光场分布在脉冲的持续过程中并不稳定，呈持续变化。对高斯型抽运的情况研究发现，减小腔长会使脉冲光场分布的不稳定性减小；而增加抽运光半径与振荡光半径之比则会使脉冲光场分布的不稳定性增加，且脉冲的平均光束质量因子会变大。

Based on the principle of Q-switched intracavity frequency doubled laser, the shape of the second harmonic pulse and the second harmonic unstable light field distribution under the various forms of pump light distribution are studied, and the variation of the second harmonic beam quality is also analyzed. It is found that the light field of Q-switched intracavity frequency-doubled laser is changing in the duration of pulse. In the case of Gaussian type of pump light, it is found that the instability will decrease when the cavity length decreases. And the instability increases by increasing the ratio of the pump light radius and that of the oscillating light, but the average beam quality factor M2 will be greater.