为了研究倍频过程对激光光束质量及光束空间分布的影响,针对典型的高阶高斯光厄米-高斯光束,采用理论计算与实验相结合的方法,得出倍频过程中不同阶数的基频光束对倍频光光束空间分布及光束质量的影响。研究结果表明,随着基频光束模式变差,倍频光束质量严重恶化。而对于相同光束质量的基频基模光束,倍频光光束质量随着入射在倍频晶体上不同的基频光光斑半径基本不变。实验中得到半导体抽运掺钕钇铝石榴石内腔倍频激光器的绿光输出功率为49.5W,波长1064nm的基频光光束质量M2＝4.93,波长532nm的倍频光光束质量M2＝10.2。结果与理论基本相符。

For typical high order modes of Hermite-Gaussian beam,the effect of frequency doubling on beam quality factor and the space distribution was studied by means of calculation and experiments.The beam quality of the frequency doubled beam was deteriorated seriously with the beam quality of basic frequency reducing.The beam quality of the frequency doubled beam was invariant when the radius of the basic beam with the same beam quality was variant in the crystal surface.Green power of 49.5W was generated with a 15kHz repetition rate by intracavity frequency doubling of a diode-pumped Nd:YAG laser.The beam quality factor of the frequency doubled beam was 10.2 with the basic beam quality factor of M2=4.93.The result of experiment was the same with the theoretical calculation.