Patent ID: 8964802
Filing Date: 2015-02-24
Classification: H01S

Abstract:
1. Optical apparatus, comprising: a ring laser-resonator formed by a plurality of mirrors; a gain-element located in the ring-laser resonator; a pump-radiation source for energizing the gain-element, thereby causing fundamental-frequency laser-radiation to circulate in the ring-laser resonator, the radiation being plane-polarized; a first optically nonlinear crystal located in the resonator and configured for type II second-harmonic conversion of the fundamental frequency; and wherein the laser-resonator is configured such that for fundamental radiation circulating exclusively either clockwise or counter-clockwise therein, the fundamental radiation makes first and second passes through the first optically nonlinear crystal per round trip in the resonator, with the first and second passes being in opposite directions, and with the polarization-planes of the first and second passes oriented at 90-degrees to each other.