Resonance expansion of quadratic quantities with regularized quasinormal modes

TL;DR

This paper introduces a quasinormal mode expansion method for quadratic optical observables using Riesz projection, enabling modal analysis of quantum light sources beyond nanophotonic resonators.

Contribution

It presents a novel approach combining quasinormal modes and Riesz projection for quadratic quantities, extending modal analysis capabilities.

Findings

Effective modal expansion of quadratic observables demonstrated

Method applicable outside the resonator region

Numerical implementation shows potential for quantum light sources

Abstract

Resonance expansions are an intuitive approach to capture the interaction of an optical resonator with light. Here, we present a quasinormal mode expansion approach for quadratic observables exploiting the rigorous Riesz projection method. We demonstrate the approach by a numerical implementation of a state-of-the-art quantum light source and emphasize the ability of the approach to provide modal expansions outside the underlying nanophotonic resonator.