Experimental observation of superscattering

TL;DR

This paper reports the first experimental demonstration of superscattering, achieved through degenerate resonances in a metasurface structure, enhancing light-matter interactions at subwavelength scales for various applications.

Contribution

It provides the first experimental evidence of superscattering in two frequency regimes using a metasurface-based multilayer structure, overcoming previous challenges.

Findings

Superscattering observed in two frequency regimes.

Demonstrated using far-field and near-field measurements.

Achieved through degenerate resonances of confined surface waves.

Abstract

Superscattering, induced by degenerate resonances, breaks the fundamental single-channel limit of scattering cross section of subwavelength structures; in principle, an arbitrarily large total cross section can be achieved via superscattering. It thus provides a unique way to strengthen the light-matter interaction at the subwavelength scale, and has many potential applications in sensing, energy harvesting, bio-imaging (such as magnetic resonance imaging), communication and optoelectronics. However, the experimental demonstration of superscattering remains an open challenge due to its vulnerability to structural imperfections and intrinsic material losses. Here we report the first experimental evidence for superscattering, by demonstrating the superscattering simultaneously in two different frequency regimes through both the far-field and near-field measurements. The underlying mechanism for the observed superscattering is the degenerate resonances of confined surface waves, by utilizing a subwavelength metasurface-based multilayer structure. Our work paves the way towards practical applications based on superscattering.