METHOD AND APPARATUS FOR GENERATING NARROWBAND COHERENT LIGHT OUTPUT FROM AN OPTICAL OSCILLATOR

摘要

An apparatus and a method are described for providing a narrowband coherent beam of optical radiation, along an optical path that is different from that of any broadband radiation which is also generated. The apparatus (10) includes an OPO (12) pumped by a laser (14) and wavelength selection means (30) disposed outside of the optical cavity of the OPO (12). The wavelength selection means (30) selects a narrowband component from a coherent output beam (28) generated by the OPO (12), and introduces the narrowband component (32) into the OPO cavity (12) as injection-seeding radiation in such a manner that, upon the introduction into said optical cavity of a second pump beam (14.2), the narrowband component (32) overlaps spatially and temporally in the nonlinear-optical gain medium of the OPO (12) with the second pump beam (14.2), thereby interacting with the nonlinear-optical gain medium of the OPO (12) to generate a narrowband second coherent output (34) in a single longitudinal mode.