Robust Topological Scattering and Radiating Structures: Bridging Free-Space Propagation and Surface Waves on Complex Objects
Abstract
In the second year of this project, my research group focused on two main areas of interest: (1) Topological and nonreciprocal electromagnetics in plasmas and plasmonic media; (2) Local and nonlocal metasurfaces. In the following, I discuss our main research accomplishments and results. (1) Topological and nonreciprocal electromagnetics in plasmas and plasmonic media. a. We investigated the implications of causality for nonreciprocal plasma media, such as the existence of a low-loss frequency window with anomalous nonmonotonic dispersion, which enables a giant and broadband nonreciprocal response. This is in stark contrast with conventional nongyrotropic passive materials, for which the frequency derivative of the permittivity dispersion function is always positive in low-loss regions. These findings may pave the way for superior nonreciprocal components in terms of bandwidth of operation and compactness, with orders-of-magnitude reductions in size. b. We theoretically demonstrated extreme field enhancements and giant broadband nonlinear effects in nonreciprocal waveguides with one-way modes. Specifically, we showed that remarkably strong field hot spots can be achieved when the unidirectional waveguiding structure is terminated with a suitable boundary that fully stops the one-way mode. Such a large field enhancement, originating from a non-resonant effect, is fundamentally different from the narrow-band field concentration effects in resonant plasmonic structures. We showed that this effect can lead to a substantial boosting of nonlinear light-matter interactions, exemplified by an improvement of several orders of magnitude in the third-harmonic-generation efficiency, which is of large significance for several applications. More broadly, our findings show the potential of extreme nonreciprocal configurations for enhanced wave-matter interactions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 28, 2022
- Accession Number
- AD1230296
Entities
People
- Francesco Monticone
Organizations
- Cornell University