Giant Enhancement of Second Harmonic Generation in One-Dimensional Nonlinear Photonic Crystal at the Oblique Incidence of Light

We present a general solution of second harmonic generation (SHG) without adopting the slowly varying amplitude approximation when light is incident obliquely upon one-dimensional(1D) inhomogeneous systems. The one-dimensional nonlinear photonic crystals consisting of ferroelectric domains with the modulated polarization direction are investigated. We find that the wavelength which is located at the photonic band edge shifts to the short-wavelength with the increasing angle of incidence. The SHG is enhanced significantly when the frequencies of fundamental wave aim at the photonic band edges and the special arrangement of the polarization directions of the ferroelectric domains is satisfied.