CTH:YAG激光器Tm-Ho准热平衡体系反转跃迁因子的数值模拟分析

Analysis of the reverse transition factor of Tm-Ho quasi-thermal equilibrium system in Cr,Tm,Ho:YAG laser

为了分析Cr,Tm,Ho:YAG激光器(以下简称CTH:YAG)系统中各种离子受激跃迁时的温度特性,从CTH:YAG激光器的适配激光速率方程出发,针对准三能级特性及Tm-Ho准热平衡体系特点,提出了反转跃迁因子的概念.采用数值模拟的方法,得到了其温度特性曲线,分析了反转跃迁因子的温度特性及其与体系储能的关系.结果表明,CTH:YAG的反转跃迁因子是温度的非线性减函数,且存在动态截止温度使得反转跃迁无法进行;截止温度与Tm-Ho准热平衡体系中的储能成正比,反转跃迁因子也随着Tm-Ho准热平衡体系的储能增大而增大;铥钬浓度比1:1是体系储能实现反转跃迁的临界点.所得结果为研究CTH:YAG激光器的温度敏感特性提供了理论依据,同时对改善和优化CTH:YAG激光器性能具有指导价值.

Based on the adaptive laser rate equations of CTH： YAG laser and in view of the characteristics of quasi-three-level Tm-Ho quasi-thermal equilibrium system, the concept of reverse transition fac- tor is introduced to analyze the temperature characteristics of Cr, Tin, Ho. YAG laser （ CTH. YAG） in the stimulated emission. By using the numerical simulation method, the temperature characteristics of the reverse transition are derived. Meanwhile, we analyze the temperature characteristics of reverse transition factor and its relationship with the system of energy storage. The results show that the re- verse transition factor decreases nonlinearly with temperature, and there exists a dynamic blocking tem- perature to prevent reverse transition; the blocking temperature is in direct proportion to the energy stored by Tm-Ho quasi-thermal equilibrium system, and the reverse transition factor also increases with the rising energy. The concentration ratio of Tm and Ho with 1 ： 1 is the critical point of the energy stor age system to stimulate the reverse transition. The above results are useful for optimizing the tempera ture dependent characteristics and output pulse capacity of CTH. YAG system.