Quasi-Phase-Matching Generation of the Second Optical Harmonic under the Pendulum Effect Conditions in Photonic Crystals

The generation of the second optical harmonic in one-dimensional photonic crystals under the pendulum effect conditions is considered for the dynamic Bragg diffraction in the Laue geometry. 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 appears due to the inclusion of the additional reciprocal lattice vector into the quasi-phase-matching condition. This vector appears due to the formation of a 2D spatial intensity lattice at the pumping field frequency under the pendulum effect. In such structures, effective quasi-phase-matchings generation of the second-harmonic waves, which are not collinear to the Bormann or anti-Bormann pumping modes, is observed.