High power self-Q-switched Tm:YAP solid state laser based on the ground state reabsorption

Abstract

The high power self-Q-switched Tm:YAP laser at 1946 nm is theoretically and experimentally investigated. Without inserting any additional Q-switching elements into the resonator, stable pulse laser of the Tm:YAP laser end-pumped by a 792 nm laser diode is successfully generated when the pump power is increased to 2.14 W. The maximum average output power of 2.77 W is obtained at the pump power of 11.7 W, with the slope efficiency of 26.4% and the optical-to-optical conversion efficiency of 23.7%. To the best of our knowledge, this is the maximum average output power in self-Q-switched solid state lasers to date. Under considering the ground state reabsorption effect, the quasi-three-level rate equation theory model for the self-Q-switched Tm:YAP laser is developed, the corresponding numerical simulation agrees with the experimental results, and the generating regime of pulse laser in the self-Q-switched Tm:YAP laser is clearly clarified. Our present research can be applied to other kinds of quasi-three-level self-Q-switched solid state lasers.