Generation of multikilowatt radially or azimuth ally polarized CO_2 laser beams by a triple-axicon optical resonator

摘要

A 2kW cylindrically polarized laser beams by using a triple-axicon optical resonator is demonstrated. The rear mirror of a commercial CO_2 laser is replaced by the optical component that is composed of a waxicon and an axicon accurately fitted together. Selection of the polarization is made by the reflectivity difference between p and s polarizations at the inclined surfaces. The reflectivity is designed to r_s>r_p so that the resonator is oscillated in azimuthally polarized mode. The output beam is converted to radially polarized beam by a converter composed of four λ/4 phase retarders. The polarization conversion efficiency is 98.5% and the power conversion efficiency is 95%.