Q-Switching of Diode Pumped Solid State Lasers

Abstract

Efficient pumping of solid state laser material by high power laser diode arrays is a subject of considerable scientific and commercial interest. These compact solid state lasers are efficient wavelength and mode converters for diode lasers, which emit around 800 nm and have a double lobed far field pattern with large divergence. The fluorescence lifetimes of solid state materials (230 microseconds for Nd:YAG, 480 microseconds for Nd:YLF, for example) offer the possibility of peak power, via Q-switching, much higher than is available from diode lasers themselves. Diode pumped lasers do not use cooling water and do not rely on broadband excitation sources (e.g. arclamps). As a result, they are not subject to water or lamp induced noise and they exhibit greatly reduced thermal lensing. These characteristics result in excellent beam properties, beam pointing stability and pulse-to-pulse stability. In this report, we will discuss performance aspects of laser diode pumped Q-switched Nd:YAG and Nd:YLF lasers, and discuss how they compare with results of a simple rate equation model.