非线性光学晶体Na_(3)La_(9)O_(3)(BO_(3))_(8)的高功率纳秒激光三倍频特性研究

Characterization of Third Harmonic Generation of High Power Nanosecond Laser on Nonlinear Optical Crystal Na_(3)La_(9)O_(3)(BO_(3))_(8)

本文对新型非线性光学晶体Na_(3)La_(9)O_(3)(BO_(3))_(8)(NLBO)三倍频产生355 nm紫外纳秒激光的特性进行了研究。以重复频率10 kHz、脉冲宽度10 ns的高功率1064 nm调Q激光器作为基频光源,采用I类相位匹配的LBO和NLBO晶体分别作为倍频晶体和三倍频晶体,获得平均输出功率152.5 mW的355 nm紫外纳秒激光输出,为目前采用NLBO晶体获得355 nm紫外激光的最高输出功率。本文还研究了NLBO晶体在实现三倍频最佳输出时晶体偏转角度随温度的变化规律,从实验角度对NLBO晶体在不同温度下的三倍频最佳相位匹配角度进行了修正。

The characteristics of 355 nm ultraviolet(UV)nanosecond(ns)laser generation using third harmonic generation(THG)method based on the new nonlinear optical(NLO)crystal Na_(3)La_(9)O_(3)(BO_(3))_(8)(NLBO)were investigated.A Q-switched high-power 1064 nm laser with repetition frequency of 10 kHz and pulse width of 10 ns was applied as the fundamental laser source.A type I phase-matched LBO crystal was used for the second harmonic generation(SHG)and a type I phase-matched NLBO crystal was used for the THG.The output power of 355 nm UV laser is 152.5 mW,and this is the highest output power of 355 nm UV laser generated by NLBO crystal.The variation of the crystal deflection angle with temperature when the NLBO crystal achieved the optimal THG output was studied,and the optimum phase matching angles at different temperatures were modified.