A Metamaterial Path Towards Optical Integrated Nanocircuits

Metamaterials are known to demonstrate exotic electromagnetic and optical properties. The extra control over manipulation of waves and fields afforded by metamaterials can be exploited towards exploring various platforms, e.g., optical integrated circuits. Nanophotonic integrated circuits have been the topic of past and ongoing research in multiple fields including, but not limited to, electrical engineering, optics and materials science. In the present work, we theoretically study and analyze metamaterial properties that can be potentially utilized in the future design of optical integrated circuits. On this path, we seek inspiration from electronics to tackle multiple issues in developing such layered nanocircuitry. We identify modularity, directionality/isolation and tunability as three useful features of electronics and we theoretically explore mimicking them in nanoscale optics. Using epsilon-near-zero (ENZ) and mu-near-zero (MNZ) properties we propose concepts to transplant some aspects of modular design of electronic passive circuits and filters into nanophotonics. We also exploit ENZ materials to develop “transformer-like” functionality in optical nanocircuits. To bring directional selectivity and isolation to this domain we develop concepts for both spatial filtering of light using ENZ layered structures as well as identifying new regimes of nonreciprocal one-way surface wave propagation on the surface of magneto-optical materials. In order to have tunability in some of the proposed concepts in this work, we numerically study a wire-medium metamaterial whose permittivity can be tuned at will. All the proposed structures have simple geometries and layered structures wherever possible, which are more convenient for analysis, design and future implementation.