FDTD simulation of an extremely thin dispersive material sheet

Summary form only given. The design of modern photonic and light-wave devices is often guided by wideband finite-difference time-domain (FDTD) simulation through which one can easily explore the desired broadband response in a single run. In most of these studies, one often encountered problem is how to efficiently simulate a super-thin material sheet as many photonic components contain coating layers with thickness ranging from sub-millimeter to several micrometers. The traditional meshing technique, when applied to directly discretize these material sheets, will result in a very data-intensive computational process. The situation gets even worse when the thin layer yet to be modeled is highly dispersive, for which extra consumption of memory is usually required to store and compute the dispersion features of the thin sheet. To sufficiently relax the above-mentioned computational burden, we propose in this abstract a three-dimensional (3-D) FDTD algorithm utilizing the so-called subcell technique (J. G. Maloney and G. S. Smith, IEEE Transactions on Antennas and Propagation, vol.40, pp.323-330, 1992) to avoid the usage of an extremely fine mesh, by representing the thin material sheet in actual numerical procedure as only a set of splitting electric-field components. As such, directly discretizing the layer is avoided and the computation cost can then be dramatically reduced. To further account for the dispersion characteristics, the auxiliary differential equation (ADE) method is employed in our model to incorporate into the algorithm the frequency-dependence properties of the thin sheet. Here, the ADE technique is chosen over the piece-wise-linear recursive convolution (PLRC) method for ease of implementation, and more importantly for its advantage of being able to simulate both linear and nonlinear dispersion. By fully including the dispersion characteristics in calculations, the algorithm reported in this abstract thus represents a more general and precise adva- cement of our previously-developed non-dispersive thin layer model (Y. Yu and C. E. Png, on the accurate modeling of an extremely thin finite-sized current sheet, IEEE Transactions on Antennas and Propagation, submitted). The technical details of the algorithm and the numerical results will be covered and discussed during the presentation.