Two-dimensional nonlinear photonic quasi-crystals: design, characterization, and applications

We describe the fabrication and characterization of partially ordered 2D photonic structures prepared by domain inversion in LiNbO3. Two types of structures have been prepared: (i) decagonal quasi-crystals designed by tiling the plane with different kinds of rhomb shaped tiles and (ii) a short-range ordered structure designed by placing randomly oriented basic units on a square lattice. Both types of structures exhibit rich sets of reciprocal vectors that may be used to satisfy the phase matching conditions for different nonlinear optical processes. As examples we describe collinear second harmonic generation of multiple wavelengths in a single decagonal nonlinear photonic quasi-crystal and cascaded third harmonic generation in a short range order nonlinear photonic crystal.