在大功率端面抽运固体激光器中, 传统Nd∶YAG晶体吸收谱线较窄, 极易受到抽运源因温度发生波长漂移的影响, 导致激光器输出功率出现起伏变化。为了降低激光器对抽运源温度波长漂移的敏感程度, 将具有优良热物性参数的Nd∶YAG晶体和具有宽吸收谱特性的Nd∶YVO4晶体相结合, 通过前后组合放置的方式, 由前端Nd∶YAG晶体吸收大部分抽运光能量, 用后端Nd∶YVO4晶体对未被吸收的抽运光能量进行补充吸收。当抽运源出现波长漂移时, 两种晶体通过互补吸收的方式, 使激光器吸收效率和输出功率保持稳定, 从而降低抽运源温度波长漂移对激光器产生的影响。实验表明, 在抽运功率97.5 W时, 这种双晶体组合方案可在抽运源工作温度为22~32 ℃内, 实现对抽运光大于90%的吸收效率, 同时激光器输出功率不稳定度小于8%, 有效改善了激光器对抽运源温度波长漂移的敏感程度。

In high power end-pumped solid state laser, the conventional Nd∶YAG crystal can be influenced by LD wavelength shift induced by temperature shift due to its narrow absorption bandwidth, which will lead to fluctuating of output power. In order to reduce the sensitivity of laser which is influenced by LD temperature, a combination crystals scheme between Nd∶YAG and Nd∶YVO4 is proposed. The Nd∶YAG with good thermophysical parameters is placed at the front end of LD to absorb most pumped energy, and Nd∶YVO4 with broad absorption spectrum at the rear of Nd∶YAG to absorb the rest pumped energy. The absorption efficiency and output power of the laser can be kept stable through the above complementary absorption during LD wavelength shift, and more tolerant to LD temperature variations. Experimental results show that the absorption efficiency of pumped energy can be improved to 90% by using the combination crystals at LD power 97.5 W in the range of LD work temperature 22-32 ℃. And the output power fluctuation is less than 8%, which reduces the sensibility to the LD temperature.