Switching from visibility to invisibility via Fano resonances: theory and experiment

TL;DR

This paper demonstrates that by exploiting Fano resonances in a homogeneous dielectric rod, one can achieve directional invisibility, offering a new approach to optical cloaking without multilayered structures.

Contribution

The study introduces a novel mechanism for light scattering suppression using cascades of Fano resonances in homogeneous dielectric objects, supported by experimental microwave demonstrations.

Findings

Suppression of light scattering in all directions for a dielectric rod.

Experimental validation using heated water to alter dielectric permittivity.

Potential for new optical cloaking and nanoparticle response analysis.

Abstract

Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering functional metadevices, as well as scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for an uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of hight-index dielectric nanoparticles and the physics of cloaking.