Electromagnetic Effects in Anti-Hermitian Media with Gain and Loss

TL;DR

This paper explores electromagnetic effects in anti-Hermitian media with gain and loss, revealing novel phenomena like lasing, wave conversion, and absorption, highlighting potential applications in optical and microwave technologies.

Contribution

It analytically investigates wave interactions in anti-Hermitian media with gain and loss, uncovering new effects and functionalities not previously demonstrated.

Findings

Lasing into surface and propagating waves

Conversion of evanescent fields to transmitted waves

Full absorption and enhanced scattering ratios

Abstract

Incorporating both gain and loss into electromagnetic systems provides possibilities to engineer effects in unprecedented ways. Concerning electromagnetic effects in isotropic media that have concurrently electric and magnetic responses, there is in fact a degree of freedom to distribute the gain and loss in different effective material parameters. In this paper, we analytically scrutinize wave interactions with those media, and, most importantly, we contemplate the extreme scenario where such media are anti-Hermitian. Considering various conditions for excitation, polarization, and geometry, we uncover important effects and functionalities such as lasing into both surface waves and propagating waves, conversion of evanescent source fields to transmitted propagating waves, full absorption, and enhancing backward to forward scattering ratio. We hope that these findings explicitly show the potential of anti-Hermiticity to be used in optical physics as well as microwave engineering for creating and using unconventional wave phenomena.