Abstract

The excitation of transverse modes in a solid-state laser has been a subject of great interest for a long time [1], because some high-order modes possess angular momentum or low divergence, and are interesting for applications such as optical tweezers, particle trapping, and microscopy. Recently, Ince-Gaussian (IG) solutions to the paraxial wave equation have attracted considerable attention. IG modes have been observed [2] and also numerically studied [3] in stable resonators. These observations occured near a degeneracy length of the cavity. High-order Laguerre-Gaussian (LG) modes can also be excited in an end-pumped solid-state laser [4] and we note that it also happens in the vicinity of a degeneracy length. In this paper, we give a comprehensive study of high-order modes in solid-state lasers, including the crucial role of the pump-induced thermal profile.

© 2015 IEEE