横流放电CO2激光的理论分析

本文提出了横流放电CO₂激光器的理论分析模型,导出了稳态发射的基本方程式,得到与熟知的非流动稳态增益饱和及功率理论相同的简单解析关系式。关系式包含了流动效应及光腔上游泵浦效应的修正项。根据强度沿流动方向变化的分析,求得饱和强度等参量在提高流速时的极限值。本文分析为文献[1—3]建议的选择平均增益系数并利用非流动稳态关系计算流动激光器特性的半经验方案提供了理论证明,同时将文献[4]提出的流动激光器的定性分析发展为定量计算。由于本文公式的简单性与非流动情况一样,因而本理论能够取代半经验方案。关键词：

A THEORETICAL MODEL FOR TRANSVERSE-DISCHARGE FLOW TYPE CO2 LASERS

A theoretical model is proposed to analyse the transverse-discharge flow type CO₂ lasers. Theoretical expressions are obtained for predicting gain-saturation and output power of flow type gas lasers, these expressions are in agreement with the well-known formulae of non-flowing gas lasers, but the former contains correction terms related to pumping action in the upstream direction of the cavity and the gas flowing effect. Based on the analysis of the variation of intensity in the direction of flow, we derive the limiting values of stauration intensity and other parameters which were attained as the flow speed was being increased. Reliability of the semi-empirical analysis suggested, in literature [1-3] for the flow type laser performance predicted by choosing an average gain-coefficient anl adopting the formulae of non-flowing gas lasers has been proved. The qualitative analysis presented in article [4] is developed into a quantitative calculation. The present model should be used in place of the semi-empirical one, since the formulae deduced are as simple as those for the non-flowing gas lasers. The results computed for both amplifier and oscillator cavities using the present model are in agreement with experimental data [1, 18-21].