Enhanced third-harmonic generation via s- and p-polarized optical surface modes of 1D photonic crystal structure

Abstract

Generation of third-harmonic radiation, visible to the naked eye as a collimated green beam, is obtained via femtosecond excitation of the optical surface modes (SMs) propagating along a one-dimensional (1D) photonic crystal (PC) for s- and p-polarizations separately. For both polarizations, the PC SMs exist at the fundamental and third-harmonic frequencies, which allows efficient nonlinear conversion at the phase-matching points. The pattern of the third-harmonic surface wave scattering is detected and modeled, and it is shown that this pattern reveals the mode structure of the PC. Applications of the studied 1D PC structure for the experimental testing of 2D nonlinear materials are discussed.