Misalignment Sensitivity of Unstable Resonators with Spherical Mirrors

Abstract

Abstract The effects of misaligning the spherical mirrors of unstable resonators on the losses, and the near and far field have been investigated both theoretically and experimentally. The theoretical description is based on the Kirchhoff integral equation of the equivalent symmetric resonator with shifted integration limits, which was solved numerically for G-parameters smaller than 2·5 and equivalent Fresnel numbers in the range up to three. Experiments were performed with a pulsed Nd-YAG system. Intensity distributions in the near and far field were recorded with an image-processing system and the losses were measured absolutely by using a previously developed method for loss measurement. Furthermore, a comparison of the misalignment sensitivity of stable and unstable resonators indicates that the latter are promising candidates for resonators, even in solid-state lasers.