Normal incidence of a plane electromagnetic wave on a periodical structure can be simulated by the finite-difference time-domain method using a single unit cell with periodical boundary conditions imposed on its borders. For the oblique wave incidence, the boundary conditions would contain time delays and thus are difficult to implement in the time-domain method. We propose a method of oblique incidence simulation, based on an iterative algorithm. The accuracy of this method is demonstrated by comparing it with the layer Korringa-Kohn-Rostoker frequency-domain method for calculation of transmission spectra of a monolayered photonic crystal.

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A subcell technique for calculation of optical properties of graphene with the finite-difference time-domain (FDTD) method is presented. The technique takes into account the surface conductivity of graphene which allows the correct calculation of its dispersive response for arbitrarily polarized incident waves interacting with the graphene.The developed technique is verified for a planar graphene sheet configuration against the exact analytical solution. Based on the same test case scenario, we also show that the subcell technique demonstrates a superior accuracy and numerical efficiency with respect to the widely used thin-film FDTD approach for modeling graphene. We further apply our technique to the simulations of a graphene metamaterial containing periodically spaced graphene strips (graphene strip-grating) and demonstrate good agreement with the available theoretical results.

In this paper we study numerically and experimentally the possibility of using metallic photonic crystals (PCs) of different geometries (log-piles, direct and inverse opals) as visible light sources. It is found that by tuning geometrical parameters of a direct opal PC one can achieve substantial reduction of the emissivity in the infrared along with its increase in the visible. We take into account disorder of the PC elements in their sizes and positions, and get quantitative agreement between the numerical and experimental results. We analyze the influence of known temperature-resistant refractory host materials necessary for fixing the PC elements, and find that PC effects become completely destroyed at high temperatures due to the host absorption. Therefore, creating PCbased visible light sources requires that low-absorbing refractory materials for embedding medium be found.