Optical parametric oscillator with unstable resonator

摘要

A high powered OPO system which produces a substantially collimated, low divergence output beam is based on the use of an unstable resonator. An optical parametric gain medium, such as beta-barium borate (&bgr;-BBO) , lithium tri-borate (LBO), cesium borate (CBO), potasium tri- phosphate (KTP), or other similar materials is mounted within the unstable resonator with suitable tuning mechanisms. Optics are provided for supplying a pump beam through the optical parametric gain medium to induce gain. In a preferred system, the unstable resonator comprises a positive branch, confocal unstable resonator. Further the unstable resonator may be injection seeded for a narrow linewidth output.