Novel Effects and Functionalities in Subwavelength Photonic and Plasmonic (Nano)Structures

Currently, within our theoretical research under the Czech Science Foundation project, we are investigating various novel effects and functionalities, connected with subwavelength (SW) photonic and plasmonic (nano)structures. Based on the development of numerical methods for the analysis of the interaction of the electromagnetic field with such structures, we have recently studied several interesting and potentially perspective problems: novel magnetooptic (MO) guiding structures with non-reciprocal properties, gain-loss guiding structures, and plasmonic structures based on hybrid dielectric plasmonic slot waveguides (with nonlinear properties). In this contribution, we present and discuss two results selected from these problems, with the concentration given to the different special modeling techniques, we have recently developed. First, we have developed a specific numerical technique – magnetooptic 3D MO aperiodic Rigorous coupled-wave analysis (aRCWA), in order to cope successfully with the complexity of wave effects in photonic nonreciprocal (one-way) structures, based on MO effects where unidirectional propagation can appear in the presence of an external magnetic field. We have then focused on the investigation of the spectral and transmission properties of structures based on InSb/dielectric waveguides at THz frequencies. Second, we have developed the nonlinear coupled-mode theory (NL-CMT) method, as and efficient tool capable of treating the Kerr-nonlinear effects (and recently also other nonlinearities). Using this technique, we have investigated the effect of loss and gain on transmission characteristics of Kerr-nonlinear directional couplers. These two examples are presented and discussed in this paper.