Theoretical Study of Diode Pumped Intracavity Doubled Passively Q-Switched Solid-State Lasers

In recent years, great attention has been paid to high peak power all-solid-state pulsed blue-green lasers [1–4] for some applications such as spectroscopy, display, optical data storage, coherent telecommunications, remote sensing, medicine, etc. Such lasers are generally realized by intracavity or external cavity frequency doubling of cw laser-diode (LD)-pumped solid-state Q-switched Nd-doped lasers. The higher nonlinear conversion efficiency from an intracavity doubling laser can be obtained due to its high fundamental wave power density in the laser resonator, which is especially so for a laser with middle or low output power. Actively Q-switched (acoustoor electro-optic switch) laser requires fast driving electronics, resulting in costly and complicated laser systems. In comparison with actively Q-switched lasers, the passively Q-switched ones contain fewer components, and are less expensive, more compact, and more reliable. Rate equations are efficient tools for analyzing the performance of a Q-switched laser. An accurate and general theoretical model of a LD-pumped passively Q-switched intracavity frequency doubling laser has been studied [5], in which the intracavity photon density is assumed to be Gaussian spatial distributions and the longitudinal variation of the intracavity photon density is also considered. Recently, Brenier et al. [6] verified the last model and report the ∗corresponding author; e-mail: [email protected]