摘要
论述了具有小纵横比（长／宽）介质的ＫｒＦ准分子激光放大器和振荡器中放大的自发辐射（ＡＳＥ）。导出了以激光负载为主的含放大的自发辐射的普适计算公式。编制了仅含纵向ＡＳＥ流变化的计算程序。分析并给出了在适度饱和增益下放大器的功率增益与抽运效率的最佳关系曲线以及相应的各参量选择值。可为ＫｒＦ激光放大器的设计及改善其光束质量提供理论参考。
AbstractThe ASE effect is one of the problems which affects the beam quality of KrF excimer laser. Italso reduces the stored energy density and extraction efficiency. In this paper, a three-dimensional formula for determining the ASE and coherent flux withinthe active volume of a laser has been given. Approximations that calculating the ASE flux onlyalong the amplifier or oscillator optical axis are introduced which allow rapid computationalspeed for low aspect ratio laser geometries. The computer code is described and verificated. It in-clude nonsaturable absorption effect, end mirror reflector effect for double-pass amplifier, andASE line-narrowing effect. The ASE and coherent flux are computed in 50 eell along thelongitudinal axis. Calculation results show that single-pass amplifier is not available, anddouble-pass amplifier which has above 40% extraction efficiency is feasible. Lo aspectratio affects more than high ones, usually it is lower than 4.0. Further, the gain-to-loss ratio is an important parameter if large power gain (>10) is to be achieved. By raising thegain-to-loss ratio as well as the gain-length product, large increase in the power gain(increased from～10 to～45 ) is achieved without degradation of the extraction efflciency. Atlast, the optimization of extraction efficiency and power gain for large KrF amplifiers is given.For oscillator geometries, high feedback leads to result that the ASE effect is low.
出处
《强激光与粒子束》
EI
CAS
CSCD
1995年第2期288-294,共7页
High Power Laser and Particle Beams
