CO_2激光器泵浦CH_3OH产生THz激光的理论分析

Theoretical Analysis of THz Laser Produced by CO_2 Laser Pumped CH_3OH

以激光速率方程理论为基础出发点,搭建出三能级系统模型,从而对光泵的CH3OH分子产生THz激光机理和动力学过程做了理论分析。结合实验参量,使用CO2激光器输出的9P(36)支线泵浦CH3OH气体分子产生118.8μm的THz激光,并在工作气压为10 Pa,温度为常温(20℃)下,分析了三能级粒子数密度变化情况及输出功率波形特征,以及改变缓冲气压、腔内温度和输出镜反射率的情况下,对激光输出功率的影响。结果表明,理论计算结果能较好地反映光泵产生THz激光的过程。

Established a model of three-energy-level system from the laser rate equation theo-ry,and then analysed the molecular dynamic processes and laser mechanism of the THz laser pro-duced by optically pumped CH3OH. According to the experimental parameters,the CO2 lasers were used to pump CH3OH to emit pulsed THz laser lines. When the 9P（36）line of CO2 lasers pumps CH3OH,the 118.8 μm line radiation was obtained,and then analysed the three-energy-level sys-tem′s particles number and the characteristics of the output waveform at the pressure of 10 Pa and the temperature at 20 ℃,as well as the influence of buffer gas pressure ,intracavity temperature and output coupler reflectivity on laser output power. The results show that the theorectical computa-tion can well reflect the process of generation of THz laser produced by optical pump.