高能电光调Q Cr,Tm,Ho∶YAG激光器

High-energy electro-optic Q-switched Cr,Tm,Ho∶ YAG laser

研究了室温运转灯泵电光调Q Cr,Tm,Ho∶YAG激光器的激光输出特性。选用高损伤阈值的掺镁LN晶体作为调Q晶体,并采用λ/4波片和平面镜组合的方式对热退偏效应进行补偿,从而实现了室温下电光调Q Cr,Tm,Ho∶YAG激光器大能量输出。在冷却水温为22℃,重复频率为1 Hz,泵浦能量为200 J的条件下,得到了单脉冲能量443 mJ,脉宽90 ns的调Q输出。理论分析了λ/4波片对热退偏效应的补偿效果,实验测量和分析了偏振片、LN晶体等调Q器件的插入损耗,并分析了激光器输出能量对重复频率的依赖现象。

The characteristics of a flash-lamp pumped electro-optic （EO） Q-switched Cr, Tm, Ho： YAG laser in room temperature is studied. By choosing a Mg-doped LN crystal with high damage threshold as the Q-switch and combining a quarter-wave plate and a flat mirror to minimize the depolarization loss, we realized the EO Q-switched output of the Cr,Tm, Ho：YAG laser and obtained high energy output. With EO Q-switched repetition rate of 1 Hz, pump energy of 200 J and temperature of 22 ℃, a laser with a output pulse energy of 443 mJ at 2.1 p,m, pulse duration of 90 ns was obtained. The mechanism and effect of a quarter-wave plate to compensate depolarization loss were analyzed. The in- sertion losses of polarizer and LN crystal were measured and analyzed. The phenomenon that the output relies heavily on the repetition rate was also analyzed.