KrF准分子激光的饱和参量与最佳激光输出

DEPENDENCE OF OPTIMIZED CONDITION OF KrF LASER OUTPUT ON SATURATION PARAMETERS

本文研究了在激光达到饱和强度下的上能级弛豫速率及泵浦速率两个参量与激光输出强度的关系。激光达到饱和强度时,上能级弛豫速率等于受激跃迁几率。根据这一特性,研究了Ar在4个大气压到6个大气压之间的四组N_(Ar)和N_(F_2),粒子数密度的Ar—Kr-F_2系统。计算了在给定激发速率和外耦合下的激光输出能量密度随Kr所占混合气体的比例而变化的关系。最后,从饱和强度下的上能级弛豫速率和泵浦速率得到了最大激光输出的条件,相应的激发速率、气压和气体混合的比例。

The dependence of the laser output energy on the upper level relaxation rate and pump rate at saturation intensity is numerically investigated. The relaxation rate of upper level is equal to the transition probability of stimulated emission. The Ar-Kr-F system with the argon pressure between four and six atm for four groups partial gas densities of Ar and F is investigated. For a given excitation rate and outcoupling, the output energy density and some parameters as a function of the krypton concentration are calculated. The maximum output of laser energy requires maximum small-signal gain g_0, namely, the ratio of the pump rate to the upper level relaxation rate (Rp /k), but also a maximum upper level relaxation rate. Finally, from the upper level relaxation rate and pump rate at saturation discussed, the optimized condition for partial gas densities, pressures and beam current densities are obtained.