中文摘要：

基于速率方程理论，建立了光抽运气体波导产生太赫兹（THz）激光的能量转化模型，理论分析并求解得到抽运光吸收系数、THz小信号增益系数以及THz输出功率表达式．计算结果表明，THz输出功率随工作物质气压的升高先增加后逐渐减少，随抽运功率的增加、输出镜反射率的减小而增加；最佳工作气压随抽运功率的增大而增大；激发态粒子数以及THz光子通量随波导截面径向逐渐减小，而THz小信号增益系数逐渐增加；抽运饱和、弱抽运吸收与激发态工作物质对THz激光的吸收是限制激光转化效率提高的根源；基于该模型的计算结果与相关文献中的实验数据符合较好．

英文摘要：

This paper, based on the rate equation theory, astablishes a model for optical pump waveguides to generate terahertz laser. By analyzing and solving the rate equation, the expressions of pump absorption coefficient, terahertz small-signal gain coefficient and terahertz output power are obtained. The calculation shows that the THz power increases first and reduces gradually with the increase of pressure of the working material, and it will increase with the increase of pumping power and the decrease of the output mirror refleetivity. The best working pressure increases with the rise of the pumping power. The number of particles in the excited state and the THz flux increase in the waveguide radial direction from the center, while the small-signal gain coefficient shows the opposite trend. Pump saturation, weak pump absorption and excited state terahertz absorption are the primary cause limiting the increase of the laser conversion efficiency. Results based on this model are in good agreement with the data from the relevant literature.