提高全固态内腔倍频绿光激光器功率稳定性的一种新方法

A new method for enhancing power stability of all-solid-state green laser with intracavity frequency doubling

报道了一种基于温控倍频KTP晶体的低噪声全固态内腔倍频绿光激光器。实验中,将KTP晶体作为1/4波片,当注入电功率为300W时,控制KTP至19.8℃获得了2.5W连续绿光,其功率不稳定度小于0.9%(10min),相比最差温度点稳定性提高约70%。理论上,从基频纵模偏振态出发,利用Jones矩阵分析了倍频KTP晶体相位延迟对谐振腔纵模振荡的影响,通过调节KTP温度改变相位延迟,有效遏制了基波偏振模耦合从而得到稳定的绿光输出。理论分析与实验结果相均合,这为低噪声全固态内腔倍频绿光激光器提供了一种新的技术途径。

The all-solid-state green laser with KTP intracavity frequency doubling has been widely used in industrial processing, military, medical field, laser display and precision measurement. But high power noise has been a major problem that plagues researchers for a long time. A low-power-noise all-solid- state green laser with KTP intracavity frequency doubling is reported for reducing green power noise in this paper. When controlling KTP to specific temperature at 19.8℃ ,with 300 W injected electric pow- er,we get 2.5 W continuous green output and the power instability is less than 0.9% （10 rain）. Com- pared with the worst case, it increases by about 70 %, significantly improving the stability of the green laser output. Based on the fundamental longitudinal mode polarization state and the Jones matrix, the influence of the phase delay of KTP on the resonator longitudinal mode oscillation is analyzed. The phase delay can be changed by controlling the temperature or the length of the KTP. By this method,the fundamental polarization mode coupling is effectively curbed, resulting in a stable green output. This provides a new way to obtain a low noise all-solid-state green laser with KTP intracavity frequency doubling with a broad application prospect.