Abstract

There are a number of work on CW intracavity SHG is reported^(1-4). Some of them are single frequency operation. However the conversion efficiency P(2ω)/P²(ω) in Ref. ¹, ². and 3 is much lower, even an order of magnitude, than in theoretical evaluation as well as the fundamental beam waists focused on the doublers are thicker in most of the reports than in the optimum focusing parameter given by Ref. ⁵. In addition our previous work⁽⁶⁾, a beta barium borate (BBC) was located at the auxiliary waist ω_opt designed to satisfy the optimum focusing parameter inside a CW single frequency ring dye laser cavity, showed also low efficiency. To look into the reasons we redo the experiments and find out it is thermal effect and deficient match of wavelengths that to abate the efficiency, to make the harmonic power can not go very high as well.

© 1992 Optical Society of America