Oscillation behavior of quasi-three-level lasers with residual resonant absorption losses

摘要

A theoretical model is developed for a quasi-three-level laser with residual resonant absorption losses existing in the unpumped or weakly pumped region of the laser medium, by taking into account the saturation nature of such absorption losses, which is described by a normalized parameter / measuring the feasibility of absorption saturation with respect to the gain saturation. Depending on the magnitude of the parameter f, the quasi-three-level laser will exhibit entirely different oscillation characteristics, distinguishing it from the four-level laser.