Displacement current sources as nonlinear interactions in optical nanocircuits

Abstract

Abstract Optical lumped circuit elements are the building blocks in the metatronics paradigm, whose goal is to extend the rules of RF circuit design into the field of nanophotonics by providing the advantages of lumpedness and modularity. In this paper, we aim at modeling within this framework nonlinear optical processes, based on the concept of optical lumped circuit elements. Displacement current sources are added to the previously introduced optical lumped elements in order to endow metatronics with nonlinear functionalities. This model not only simplifies the analysis of the nonlinear processes, but paves the road to develop nonlinear optical components and devices in this paradigm. Second- and third-order nonlinearities are investigated analytically in the case of a nanosphere. A step by step example of modeling a LiNbO3 nanorod, which is close to a practically realizable structure, is also presented. The results are compared with those of a full-wave simulation and the significance of the proposed model is discussed.