Simultaneous perfect phase matching for second and third harmonic generations in ZnS/YF(3) photonic crystal for...

Theoretically designed and experimentally realized simultaneous perfect phase matching of second and third harmonic generations were demonstrated in a one-dimensional ZnS/YF(3) photonic crystal (PC) structure. Dramatic enhancement of second harmonic generation (SHG) and third harmonic generation (THG) in forward and backward directions near the photonic band edge were observed. This enhancement came from a combination of large ZnS nonlinear susceptibility coefficients, high density of optical modes and perfect phase matching of the fundamental and the harmonic waves near the photonic band edge due to modification of the dispersion curve by the PC structure. Total SHG and THG conversion efficiency over 4% is measured in only six micrometers length of photonic crystal. Theoretical calculations show good agreement with experimental measurements.