Spectral analysis of the Neumann--Poincar\'{e} operator on the crescent-shaped domain and touching disks and analysis of plasmon resonance

TL;DR

This paper provides a detailed spectral analysis of the Neumann--Poincaré operator on crescent-shaped and touching disk domains, revealing its spectral properties and implications for plasmon resonance.

Contribution

It offers the first complete spectral resolution of the Neumann--Poincaré operator on these domains, showing it has only absolutely continuous spectrum on [-1/2,1/2].

Findings

The operator has only absolutely continuous spectrum on [-1/2,1/2].

Spectral resolution is achieved via Fourier transform on boundary circles.

Application to plasmon resonance analysis on crescent-shaped domains.

Abstract

We consider the Neumann--Poincar\'{e} operator on a planar domain enclosed by two touching circular boundaries. This domain, which is a crescent-shaped domain or touching disks, has a cusp at the touching point of two circles. We analyze the operator via the Fourier transform on the boundary circles of the domain. In particular, we define a Hilbert space on which the operator is bounded, self-adjoint. We then obtain the complete spectral resolution of the Neumann--Poincar\'{e} operator. On both the crescent-shaped domain and touching disks, the Neumann--Poincar\'{e} operator has only absolutely continuous spectrum on the closed interval $[-1/2,1/2]$. As an application, we analyze the plasmon resonance on the crescent-shaped domain and touching disks.