<title>Unstable multirod Nd:YAG lasers with variable reflectivity mirrors</title>

Abstract

Different unstable resonator schemes are described, taking into account that the laser rod acts like a varying thermal lens. The single rod resonators can be extended to contain two or three rods. With l5Omm*lOmm Nd:YAG rods, the presented resonator designs were investigated experimentally. Output power and beam parameter products as well as the influence of the thermal lens on the focusability were measured. The sensitivity of output power and beam steering to mirror tilt is presented and the design of the variable reflectivity mirrors is described.