本文研究了一种在激光谐振腔内额外加入晶体以优化谐振腔稳定性的方式, 通过在谐振腔内加入折射率合适的晶体有效提高了激光输出性能。本工作搭建了一台Nd3+∶Gd0.1Y0.9AlO3(Nd∶GYAP)晶体激光器, 并在激光谐振腔内置入LBO晶体, 研究对比了LBO对b切和c切晶体激光性能的影响, 以及有无LBO时的激光器性能, 包括输出功率、激光波长、光束质量和偏振特性。结果表明, 当在激光谐振腔内置入LBO后, 光谱和光束质量基本没有发生变化, b切Nd∶GYAP激光器的斜率效率从18.9%提高到24.3%, c切Nd∶GYAP激光器的斜率效率从2.87%提高到10.07%, b切晶体的最大输出功率从0.931 W增加到1.254 W, c切晶体的输出功率从63 mW增加到134 mW。置入LBO后, 输出激光的偏振由于旋光现象也会在一定程度上发生偏转。因此, 在一些必须延长腔长的情况下, 如调谐和锁模操作中, 该工作为其提供了一种提高激光器斜率效率和输出功率的方法。

A method of optimizing the stability of the resonant cavity by adding an additional crystal into the laser resonant cavity is studied for the first time. The laser performance can be effectively improved by adding crystals with appropriate refractive index into the resonant cavity. In this study, a Nd3+∶Gd0.1Y0.9AlO3 (Nd∶GYAP) crystal laser device was built, and LBO crystal were added into the resonant cavity. The effects of LBO crystal on the laser properties of b-cut and c-cut crystals were compared respectively. The laser performance with and without LBO crystal was characterized in terms of output power, laser wavelength, beam quality and polarization characteristics. When LBO crystal is inserted into the laser resonant cavity, the slope efficiency of b-cut Nd∶GYAP increases from 18.9% to 24.3%, and that of c-cut Nd∶GYAP increases from 2.87% to 10.07% without changing the spectrum and beam quality. The maximum output power of b-cut crystal increases from 0.931 W to 1.254 W, and that of c-cut crystal increases from 63 mW to 134 mW. However, the polarization of the output laser deflects to some extent due to the optical rotation effect. This research provides a way to improve the slope efficiency and output power of lasers in the cases of the cavity length must be extended such as tuning and mode-locking operations.