Designing electromagnetic resonators with quasinormal modes

TL;DR

This paper reviews how quasinormal modes (QNMs) are used to design and analyze micro- and nanoresonators in photonics, emphasizing their physical insights and computational advantages.

Contribution

It provides a comprehensive overview of recent applications of QNM theory in designing and understanding electromagnetic micro- and nanoresonators.

Findings

QNMs offer deep physical insights into resonator behavior.

QNM theory enhances computational efficiency in complex scenarios.

Recent developments have matured the electromagnetic theory of QNMs.

Abstract

Micro- and nanoresonators, which enable light trapping in small volumes for extended durations, play a crucial role in modern photonics. The optical response of these resonators is determined by their fundamental resonances, known as quasinormal modes (QNMs). Over the past decade, the electromagnetic theory of QNMs has undergone significant development and has now reached a level of maturity that allows its reliable application to numerous contemporary electromagnetic problems. In this review, we explore recent applications of QNM theory for designing and understanding micro and nanoresonators. We highlight why QNMs provide deep physical insights and enhance computational efficiency in scenarios involving mode hybridization and perturbation.