Light amplification and scattering by clusters made of small active particles: the local perturbation approach

TL;DR

This paper investigates how clusters of small active particles can amplify and scatter light, revealing that even single particles can achieve amplification, especially near resonance frequencies, supported by analytical and numerical analysis.

Contribution

It introduces an analytical and numerical approach combining the local perturbation method and laser theory to study light amplification in small particle clusters.

Findings

Light amplification can occur with a single small particle.

Amplification is enhanced near the cluster's morphological resonance.

Numerical results show scattering behavior for ordered and disordered particle arrangements.

Abstract

The light amplification by finite active media is used extensively in modern optics applications. In this paper the light amplification and scattering by cluster of small particles is studied analytically and numerically with the help of the local perturbation method and phenomenological laser theory. It is shown that light amplification is possible even for one small particle, and that the amplification is more profound when the light frequency nears the frequency of the cluster's morphological resonance. Theoretical discussions are supplemented by numerical results for scattering by clusters which particles positioned at ordered and at slightly disordered positions.