Efficient intracavity second harmonic generation

A method for intracavity generation of the second harmonic of unpolarized laser radiation was devised and tested experimentally. The harmonic was generated in a new type of nonlinear converter which performed vector phase matching of orthogonally polarized waves of the fundamental frequency with parallel ray vectors. This converter was capable of spatial separation of the fundamental and second-harmonic radiation and of increasing considerably the harmonic generation efficiency.