DEVELOPING ELECTROMAGNETIC AND PHOTONIC DEVICES BY USING ARTIFICIAL DIELECTRIC MATERIALS

Abstract

Transformation-Optics (TO) is a new theoretical tool that allows for designing advanced electromagnetic and photonic devices. TO theory often prescribes material parameters for transformed media that cannot be found in nature. Metamaterials (MMs) were initially used for realization of TO-based devices. However, conventional MMs possess noticeable losses caused by their metallic parts that prevents their utilization in optical range. Alternatively, photonic crystals (PhCs) formed from arrays of low-loss all-dielectric elements can be good substitutes for building TO-prescribed devices. Metasurfaces (MSs) comprised from 2D arrays of dielectric resonators (DRs) have been found as other promising candidates for realizing flat and efficient devices. In our work, we explored incorporation of all-dielectric artificial media in invisibility cloaks, representing the most exciting TO application, wave collimators, and MSs. We studied associated electromagnetic and photonic phenomena and solved engineering problems met at the development of device prototypes. We designed and used anisotropic PhCs composed of rectangular lattice dielectric rod arrays to build up a cylindrical cloak medium realizing prescriptions of TO (Chapter 2). We also formed another cylindrical invisibility cloak by utilizing the self-collimation phenomenon in PhCs without considering TO prescriptions for turning the wave in the cloak medium (Chapter 3). Furthermore, we designed a wave collimator by employing high-anisotropic rectangular lattice dielectric rod arrays with unidirectional near-zero refractive indices (Chapter 4). Then, we studied the resonance and scattering responses of MSs composed of dielectric disks, while altering the periodicity of MSs. Our results demonstrated that periodicity of arrays has significant influence on defining the responses of MSs. (Chapter 5). Increasing lattice constants of dielectric MSs provided us with an opportunity to investigate interactions between lattice resonances (LRs) and dipolar electric and magnetic resonances that affected characteristics of MSs (Chapter 6). We analyzed the formation of Fano responses and wave interference processes in dense MSs to reveal the nature of electromagnetically induced transparency (EIT) that was detected at the frequency of electric dipolar resonance. (Chapter 7).