定向棱镜腔改善重频DPL光束质量的研究

Study on directional prism resonator to improve the laser beam quality of repetition rate DPL

影响重频DPL光束质量的主要因素包括谐振腔的失谐、非均匀光泵浦以及工作物质的热效应。定向棱镜作为全反射镜与平面输出镜构成简单的自准直、不失调介稳腔结构,实现对侧向泵浦DPL的增益匀化、热效应的光学补偿以及光轴的自纠偏。通过实验发现:定向棱镜谐振腔在热传导冷却、Cr4+:YAG被动调Q 的侧向泵浦DPL中, 40 Hz运行时, 0.532 μm输出能量为52.2 mJ/pulse,稳定度为0.5%,脉宽7.5 ns, 频率稳定度0.025%,远场束散角为2.8 mrad,2小时内光轴指向近乎零漂移,远场光束分布稳定。

The factors that deteriorate beam quality of repetition DPL include maladjustment of resonator, un-even distribution of pumped light and thermal effect of working medium. Directional prism is as entirely reflect mirror which builds up critical resonator with piano output mirror, and it realizes symmetry gain in side pumped cavity, optical compensation to thermal effect and optical axis self-correction. Directional prism resonator works in Conductive cooling, side pumped DPL with frequency of 40 Hz, experiment results are as follows: 0.532 μm laser energy is of 53.2 mJ, stability of output energy is of 0.5%, pulse width is of 7.5 ns and the stability of frequency is of 0.025%, original beam divergence is of 2.8 mrad, laser axis is nearly nil-drift in two hours, and the beam distribution in far field is steady.