Inverse design in the complex plane: Manipulating quasinormal modes

Utilizing the fact that the frequency response of a material can be decomposed into the quasinormal modes supported by the system, we present two methods to directly manipulate the complex frequencies of quasinormal modes in the complex plane. We first consider an eigenpermittivity approach that allows one to find how to shift the permittivity of the structure everywhere in order to place a single quasinormal mode at a desired complex frequency. Secondly, we then use perturbation theory for quasinormal modes to iteratively change the structure until a given selection of quasinormal modes occurs at desired complex frequencies.

Automated summary

This study presents two methods to directly manipulate the complex frequencies of quasinormal modes in a material. The first method involves using eigenpermittivity to shift the structure and place a desired quasinormal mode at a specific frequency. The second method uses perturbation theory to iteratively modify the structure until a desired selection of quasinormal modes occurs at desired complex frequencies.