Laser system and frequency conversion method

PURPOSE: To propose a laser system for generating a type 2 nonlinear second harmonics beam, using a nonlinear ring resonator. CONSTITUTION: The reflection surfaces of a nonlinear ring resonator 10 are all symmetrical with respect to a crystal axis, thus resonating beams that are polarized so that they orthogonally cross along a same beam path 22 in the resonator 10 without being subjected to multiple reflection.