Discontinuous phase elements for transverse mode selection in laser resonators

Abstract

Discontinuous phase elements can be inserted into laser resonators so that the lasers will operate with only one desired high order transverse mode. These elements introduce sharp discontinuous phase changes so as to result in minimal losses for a desired transverse mode but high losses to others. The basic principles, along with experimental results with Nd:yttrium–aluminum–garnet and CO2 lasers, illustrating improved output powers with a high beam quality of low divergence, are presented.