体布拉格光栅外腔倍频半导体激光器研究

为提高绿光激光器的输出特性，设计了一种体布拉格光栅外腔倍频半导体激光器。采用反射型体布拉格光栅作为反馈元件构成外腔半导体激光器，并使用三硼酸锂晶体进行倍频，研究了基频光的光束及光谱特性对倍频光的光束及光谱特性的影响。实验结果表明，使用体布拉格光栅进行外腔锁波时，所得到的倍频光同样能实现窄带宽输出，同时倍频光的远场分布与基频光的远场分布一致。使用衍射效率为10%的体布拉格光栅作为外腔输出镜，可将半导体激光器的输出波长稳定锁定在1 064 nm，所得到的倍频光波长稳定在532 nm附近，光谱线宽压缩至0.4 nm左右，输出功率可达73 mW。

Study on volume Bragg grating external cavity second harmonic generation semiconductor laser

To improve the output characteristics of green light lasers, a volume Bragg grating external cavity second harmonic generation semiconductor laser is designed. A reflective volume Bragg grating was used as a feedback element to construct an external cavity semiconductor laser, and a lithium triborate crystal was used for second harmonic generation. The influence of the beam and spectral characteristics of the fundamental frequency light on the beam and spectral characteristics of the frequency doubling light was studied. The experimental results showed that when volume Bragg grating for external cavity mode locking was used, the obtained second harmonic generation also could achieve narrow bandwidth output, and the far field distribution of second harmonic generation was consistent with that of fundamental frequency light. A volume Bragg grating with a diffraction efficiency of 10% was used as an external cavity output mirror. The output wavelength of the semiconductor laser could be stably locked at 1 064 nm. The obtained second harmonic generation wavelength could be stabilized around 532 nm. The spectral linewidth was compressed to about 0.4 nm, and the output power could reach 73 mW.