Design And Optimization Of The Optical Cavity Of Optically Pumped Alkali Vapor Laser

Being a hotspot of laser research field, optically pumped alkali vapor lasers(OPALs) have been developing rapidly in recent years. They have the advantages of both solid lasers and gas lasers, and possess some desirable features such as the good thermal management, the narrow line width, the high beam quality and etc.. OPALs could find many potential applications in laser cooling, directed energy transmission, material processing and military defense and so on. During the past decades, scientists deeply carried out many experimental and theoretical researches on optical pumped alkali vapor lasers and gained some desirable results. However, there is still a lack of theoretical researches related to the mismatch of cavity mode and pumped laser beam as well as the optimization of laser cavity. So, it is significant to do the research on the design and the optimization of the optical cavity for improving the output performance of OPALs.This paper aims to design and optimize the parameters of the stable laser cavity with a flat and a concave mirrors according to the various laser cavity structures reported in the experimental design of optically pump alkali vapor lasers. Gaussian beam is used to describe the transmission of pump light and laser beam in the optical system, a brief physical model is established to analysis the parameters of the stable resonant laser cavity by taking the flat-concave cavity as a confocal cavity. By deeply analyzing the kinetic model on OPALs and the simulation results, we find the relationship of the optical cavity parameter with the slope efficiency to evaluate the performance of optically pumped alkali vapor lasers. Considering the difference of pump and laser beam radius in the cavity, we redefine the mode matching coefficient. Taking longitudinally pumped Cs vapor laser for example, we analyze influences of some parameters of the pump light, the coupling lens, the alkali vapor cell, the optical cavity to the mode matching coefficient. The results provide a theoretical way for optimizing the design of various laser cavities and improving the output performance of optically pumed alkali vapor lasers.