Perturbation Theory for Plasmonic Modulation and Sensing

TL;DR

This paper introduces a perturbation theory for small changes in dispersive plasmonic nanostructures, enabling better design of sensors and optical devices by providing accurate predictions and new physical insights.

Contribution

It develops a general perturbation framework for dispersive plasmonic systems, validated against numerical calculations, and explores new optical behaviors related to plasma frequency modulation.

Findings

The theory accurately predicts changes in plasmonic systems.

Numerical validation confirms the theory's precision.

New optical behaviors are identified related to plasma frequency modulation.

Abstract

We develop a general perturbation theory to treat small parameter changes in dispersive plasmonic nanostructures and metamaterials. We specifically apply it to dielectric refractive index, and metallic plasma frequency modulation in metal- dielectric nanostructures. As a numerical demonstration, we verify the theory's accu- racy against direct calculations, for a system of plasmonic rods in air where the metal is defined by a two-pole fit of silver's dielectric function. We also discuss new optical behavior related to plasma frequency modulation in such systems. Our approach provides new physical insight for the design of plasmonic devices for biochemical sensing and optical modulation, and future active metamaterial applications.