Cascades of Fano Resonances in Scattering by a Mesoscale Spherical Particle in the Superresonance Mode

TL;DR

This paper explores the phenomenon of Fano resonance cascades in mesoscale dielectric spheres under broadband illumination, revealing high-Q superresonance modes that enable subdiffraction field localization and deepen understanding of super-resolution physics.

Contribution

It introduces the concept of Fano resonance cascades in superresonance modes of mesoscale spheres and analyzes their conditions, amplitude modulation, and potential for super-resolution applications.

Findings

High-quality factor superresonance modes (Q≈10^7) identified.

Conditions for quasi-periodicity of superresonance peaks established.

Refractive index influences amplitude modulation of Fano cascades.

Abstract

Broadband light illumination of a mesoscale dielectric sphere makes it possible to reveal new effects that associated with super resonance mode. These include the possibility of generating high-order Fano resonance cascades. The quality factor has the order Q=10^7. Super-resonance-enabled subdiffraction fields localization by mesoscale dielectric sphere under broadband light illuminations (e.g., at wavebands of 400 - 700 nm for refractive index of sphere n=1.5-1.9 and 1500 - 1600 nm for n=3.47) have been investigated. The conditions for the quasi-periodicity of superresonance peaks are established. The dependence of the amplitude modulation of Fano cascades on the refractive index of the sphere is shown. These results are important in deep understanding of physics of the super-resolution mechanism related to superresonance mode and will find great potential applications in many other area.