Rumen Iliew

We propose a nonlinear all-photonic-crystal (PhC) Fabry–Perot cavity tuned to the subdiffractive regime of the interior PhC, and we study angular-resolved nonlinear propagation of monochromatic plane wave excitations. With rigorous numerical simulations, we show that, for sufficiently large negative pump detunings and a focusing nonlinearity, the transmitted field has a bistable dependence on the pump field. Moreover, we reveal that, in contrast to a homogeneous resonator for different inclinations, the hysteresis curve is virtually unchanged for a fairly wide angular range. This may pave the way for obtaining novel kinds of nonlinear localized solutions in driven nonlinear resonators.

We study theoretically forward and backward second-harmonic generation in a two-dimensional photonic crystal structure made of lithium niobate. The aim of this article is twofold: First, we propose a reliable modal algorithm for describing the light propagation taking into account the vectorial character of the interacting fields as well as the tensorial character of the nonlinearity and verify it by means of the nonlinear finite-difference time-domain method. Second, we propose a photonic crystal where we obtain a giant efficiency increase for backward second-harmonic generation with slow light. DOI: http://dx.doi.org/10.1103/PhysRevA.81.023820 © 2010 The American Physical Society

We propose subdiffractive all-photonic crystal Fabry–Perot resonators and study light propagation in this novel system. The photonic crystal in the cavity is tuned to the subdiffractive regime and the mirrors to the center of the photonic bandgap. We show that such all-photonic crystal resonators exhibit a broadband angular transmission at a fixed frequency and a high Q factor, resulting in a drastic reduction of the power threshold for all-optical switching.

We predict an enhanced efficiency of collinear second-harmonic generation in photonic crystals. This can be achieved by taking advantage of the complexity of the dispersion relation in periodic lattices. Thus, two essential conditions for increasing the nonlinear interaction, namely, phase matching and small group velocity (slow light), can be met simultaneously. The analytical results based on a modal approach are verified with rigorous simulations by means of the finite-difference time-domain method. The influence of material dispersion on optimal phase match is discussed.