摘要
本文建立了适用于国内首次运转的千瓦级横流闭循环自持放电ＣＯ激器的理论模型．该模型包含了互相耦合的电子能量分布函数的玻尔兹曼方程、分子振动态动力学方程、一维流体力学方程和谐振腔增益损耗方程。与过去的理论不同点是，对于大功率激光器放电过程，考虑了第二类碰撞的消激发作用。在分子动力学方面，考虑了电子直接振动出发、Ｖ－Ｖ过程、Ｖ－Ｔ过程、自发发射和受激发射共５种过程。计算结果表明，电子能量分布函数明显地偏离玻尔兹曼分布，且强烈地依赖Ｅ／Ｎ值和分子振动态的分布，而对气体温度不敏感。对千瓦级单程谐振腔输出功率计算表明，在人口温度由１２０Ｋ升高到２００Ｋ，其转换效率由１８％下降到７％，最佳输出耦合为１５～２０％；对千瓦级三程谐振腔的计算表明，在人口温度由１２０Ｋ升高到２００Ｋ，其转换效率由３４％下降到１２％，计算结果与实验基本一致。
A theoretical model has been established.lt can be applied to the first kilowatt transverse flow closed-cycle self-sustained discharge CO laser in China. The model consists of the Boltzmann equation for electron energy distribution function, vibrational kinetic equations of molecules,one-dimension flow equations and gain and loss equations of the resonator. All these equations are coupled with one another.The model diners from the past models in that it allows for the deexcitation by second kind of Collision.for high power CO laser. Five processes are considered on aspect of molecular kinetics: direct vibrational excitation by electron impact,V-V and V-T collisional energy transfer, spontaneous and stimulated emission. The results of calculation indicate that the distribution function of electron energy is obviously deviated from the Boltzmann distribution with a strong dependence on the value Of E/N and the vibrant nonal pOPulation distribution of molecules, but insensitive to the gas temperature. The calculation of output power indicates that when the entrance gas temperature increases from 120Kto 200K,the conversion efficiency decreases from 18%to 7%with optimum output couple coefficient between 15%and20%for single-pass resonator,from 34%to12%for the three-pass resonator, A good agreement of the calculated data with experiments is reached.
出处
《量子电子学》
CSCD
1995年第2期113-125,共13页
基金
国家自然科学基金
