This research will study a novel embedded self-locking technique as an approach to second-harmonic generation (SHG) of a diode laser output in an external unidirectional resonant ring cavity. The proposed scheme is capable of providing both high conversion efficiency and good spatial beam quality with very low amplitude noise, and has two other advantages over previous cavity and feedback schemes. First, it allows linear polarization to be maintained within the external cavity, which is necessary for an efficient Type I SHG. Second, the use of a three-mirror unidirectional resonant cavity, instead of the standing wave cavity, will substantially improve the SHG efficiency. Furthermore, the three-mirror triangular cavity design is easy to align and maintain high position- stability, when compared to the four-mirror cavity approach. The novel power-build-up resonant cavity proposed in this approach offers a promise of a fundamental power-enhancement factor of 200 and an external SGH conversion efficiency over 40%.
