Observation of simultaneous generation of multiple harmonies in hexagonally poled lithium niobate

Summary from only given. The idea of quasi-phase-matching (QPM) a nonlinear process by periodically inverting the nonlinearity was first applied to one-dimensional structures. Later the concept was extended to include multi-dimensional structures, known as nonlinear photonic crystals (NPC). The main advantage of 2D NPCs is the wealth of reciprocal lattice vectors (RLV), both in terms of direction and size, which allows multiple nonlinear interactions to occur simultaneously. Here we report the first observations of simultaneous 2-nd, 3-rd and 4-th harmonic generation in a 2D NPC.