Quasi-synchronous generation of the second optical harmonic under the pendulum effect in photonic crystals

Generation of the second optical harmonic in one-dimensional photonic crystals under conditions of the pendulum effect with dynamic Bragg diffraction in the Laue geometry is theoretically considered. It is shown that in photorefractive photonic crystals, as well as in photonic crystals with photoinduced quadratic nonlinearity, a new direction of quasi-phase-matching generation of the second harmonic arises due to the inclusion of an additional reciprocal lattice vector in the quasi-phase-matching condition. This vector appears due to the formation of a two-dimensional spatial intensity grating at the frequency of the pump field during the pendulum effect. In such structures there occurs efficient quasi-phase-matching generation of second-harmonic waves that are not collinear to the Bormann or anti-Bormann pump modes.