Wave scattering by objects made of small particles with oscillating permittivity

TL;DR

This paper investigates wave scattering by small particles with periodically varying refractive index, revealing how oscillating permittivity influences resonance frequencies and scattering spectra through theoretical and numerical analysis.

Contribution

It introduces a formalism for analyzing wave scattering by particles with oscillating permittivity, applicable to arbitrary shapes, and demonstrates its effects on resonance shifts and spectrum features.

Findings

Oscillating permittivity shifts existing resonances.

New scattering resonances emerge due to permittivity oscillations.

Resonance frequencies and scattering spectra are significantly affected.

Abstract

Rapid advancements in the micro and nano-technology create unlimited opportunities for design of novel optical materials and their applications. Recently, the possibility of the fast refractive index modulation was demonstrated in semiconductors. In this paper we study the wave scattering by small dispersionless particles with periodically varying refractive index in scalar case by using the local perturbation method. The used formalism allows us to study theoretically and numerically the scattering by objects made of small particles of arbitrary shape and with oscillating refractive index. In this work, the field scattered by the cluster of the particles and its resonance frequencies are calculated theoretically. In addition, the results of the numerical modeling of the scattering by single cube and by cluster of cubes with oscillating permittivity are presented. It was shown that the scattered fields and their resonance frequencies are significantly affected by the oscillating permittivity: existing resonances are shifting, new scattering resonances are emerging, and deeps in the scattering spectrum are appearing.