Phase matching characteristics of second-harmonic generation in periodic 90 degrees-Domain structures of KNbO3

Abstract

Phase matching characteristics of second-harmonic generation (SHG) in periodic 90 degrees-domain structures of KNbO3 single crystal were extensively analyzed. Important parameters including types of interaction and the corresponding effective nonlinear optical coefficients, grating periods for quasi-phase matching (QPM), spectral bandwidths, and group velocity mismatches were estimated. The results show that KNbO3 with a specific internal structure of periodic 90 degrees-domains can be used for efficient narrowband second-harmonic generation and group-velocity-matched broadband optical frequency doubling near the optical communication window.