Tm,Ho双掺调Q激光系统理论与实验研究

本文针对Tm,Ho双掺的激光系统,利用速率方程理论,得出了激光各能级的反转粒子数分布规律.通过计算预测出了超过1 ms的时间有巨脉冲的光子输出,脉冲能量为88.4 mJ,脉冲宽度为426 ns.实验采用环形腔声光调Q,Tm,Ho:LuLF为激光介质,三向侧面抽运.自由运转和调Q状态的斜率效率分别为6.36%和2.9%.注入能量3.25 J时,自由运转激光能量103.2 mJ,调Q激光能量为30.3 mJ,对应光-光效率为3.17%,0.93%;注入能量3.5 J时,自由运转激光能量为129.3 mJ,调Q激光能量35.9 mJ,对应光-光效率为3.69%,1.02%.最大的动静比为32.8%.激光脉冲宽度为417.2 ns.如果环形腔能够单向运转,那么得到的激光能量和光-光转换效率都将增大一倍,与预测结果更加一致.

Theoretical and exp erimental researches on Tm and Ho co dop ed Q-switching laser

The distribution of population inversion has been obtained by solving the rate equations of a Tm and Ho codoped laser system. A giant pulse laser output of 88.4 mJ with pulse duration of 426 ns has been predicted at 0.1% duty cycle of LD pump source. In a 2 m ring resonator, the Tm, Ho:LuLF laser material has been side-pumped from three directions and Q-switched for acoustic-optic device. The slope efficiency is 6.36% in free running mode and 2.9% in Q-switching mode. When 3.25 J pump energy in 1 Hz repetition frequency is injected, it has been demonstrated that the laser pulse energy of 103.2 mJ with an optical-to-optical efficiency of 3.17% in the free running mode and 30.3 mJ with 0.93% optical-to-optical efficiency. When 3.5 J pump energy is injected, it has been obtained that the pulse energies of 129.3 mJ and 35.9 mJ in the two modes with optical-to-optical efficiencies of 3.69% and 1.02% respectively. The greatest dynamic to static ratio is 32.8%. The pulse duration is 417.2 ns when 3.25J pump energy is injected. If the ring resonator operates unidirectionally, the laser energy and the corresponding optical efficiency will be doubled, the result being in agreement with the theoretical analysis of rate equations.
Keywords： Tm Ho:LuLF rate equations energy transfer Q-laser