Modeling Analysis of Optical Bistability in Continuous-Wave Operation of Quasi-Three-Level Lasers

In this paper, an analytical model is developed for a quasi-three-level laser exhibiting optical bistability in its continuous-wave operation. This model gives the necessary conditions for the formation of such bistability, which are directly connected to measurable parameters of the laser medium, and reveals most of the primary characteristics of optical bistablity demonstrated experimentally with quasi-three-lasers based on Yb-doped vanadates. The principal parameters characterizing such bistability, x_{thmathchar"702}D up, x_{thmathchar"702}D down, Δx_br, I_{thmathchar"702}D up, and I_{thmathchar"702}D down, can be expressed explicitly in terms of two normalized parameters, xa = 2αa0pa/δ and f = I_sat,a/I_sat,m. To confirm its validity and demonstrate its usefulness, this model is applied to a typical Yb:LuVO₄ laser displaying sizable optical bistability in its operation, giving very good agreement between theoretical prediction and experimental measurement.