CW second harmonic generation with elliptical Gaussian beams

We present a study of the efficiency and optimization of cw second harmonic generation by elliptical Gaussian laser beams. Elliptical focusing slightly improves conversion efficiency and reduces crystal damage risk when heavy walk-off is present. Single-pass measurements of the efficiency for doubling 515-nm radiation in beta-barium borate (BBO) agree with theory. Thermal effects, caused by radiation absorption, limit the doubling efficiency of single-frequency radiation in an external enhancement ring cavity.