Tm：YLF激光器弛豫振荡问题的理论研究

Theoretical Study of Relaxation Oscillation in Tm：YLF Laser

鉴于Tm：YLF激光器的弛豫振荡容易引起激光器输出功率不稳定及光学元件的膜层损伤等问题，并且影响它在高重频几十kttz Ho：YAG激光器中的应用，本文从理论上分析了Tm：YLF激光器的弛豫振荡频率和弛豫振荡幅度，分析表明：Tm：YLF激光器的弛豫振荡频率随泵浦功率、谐振腔长度、输出镜反射率和激光上能级寿命的增加而增加；可以通过增加激光谐振腔Q值的办法来抑制弛豫振荡中的尖峰幅度。弛豫振荡是固体激光器研究中经常遇到的问题，是引起固体激光器输出波动的最重要机理，通过对Tm：YLF激光器弛豫振荡问题的理论研究，试图发现抑制Tm：YLF激光器连续工作时的尖峰脉冲现象的方法，从而实现激光功率信号的平滑无尖峰输出。

The relaxation oscillation of the Tm：YLF laser may lead to the damage of optical coating, and to have adverse impacts on its applications in Ho ： YAG laser at pulse repetition frequency of tens of kHz. The relaxation oscillation frequencies and relaxation oscillation amplitude of the Tm： YLF laser were analysed in theory. The a- nalysis has shown that the relaxation oscillation frequency of the Tm：YLF laser increases with pump power, length of resonant cavity, output mirror reflectance and laser- level lifetime. The relaxation oscillation ampli- tude can be controlled by changing the Q - value of the laser resonator. Relaxation oscillation is a problem fre- quently encountered in the study of solid-state lasers. It is the most important mechanism of power fluctuations in solid-state lasers. This work tries to find ways to suppress pulse spikes and obtain smooth laser power signal in continuous wave Tm：YLF laser through theoretical study of relaxation oscillation in Tm：YLF laser.