A resonantly pumped three-level laser is analysed in a high-Q cavity under conditions of negligible and high pump depletion to obtain expressions for the emission characteristics in analytic form. Under high pump depletion our analysis predicts bistable emission in its steady state behaviour.
Uppal, J. S., Harrison, R. G., & Lu, W. (1990). Analysis of Steady-State and Bistable Emission from a 3-Level Laser. Journal of Modern Optics, 37(4), 605-611. https://doi.org/10.1080/09500349014550691