Theoretical Analysis of Multimode Pumped Second-Harmonic Generation

Abstract

Type I and Type II second-harmonic generations (SHG) with a randomly phased multimode pump have been theoretically analyzed by considering phase mismatch and fundamental bandwidth effect. The equations obtained in the paper are formulated in a very concise and analytic form, which can be used to evalute both conversion efficiency and spectrum. We found that the previously recognized multimode enhancement effect does not exist in Type II SHG. The issue of harmonic instability due to multimode pumping has been also discussed.