Topological origin of electromagnetic energy sinks

TL;DR

This paper reveals that electromagnetic energy sinks with enhanced fields originate from topological effects and bulk-edge correspondence breakdown in nonreciprocal and reciprocal optical systems, enabling efficient energy absorption.

Contribution

It demonstrates the topological origin of electromagnetic energy sinks and introduces new designs using nonreciprocal and P-T-D symmetric platforms for ultra-singular field enhancement.

Findings

Energy sinks can be realized in nonreciprocal continua with no spatial cut-off.

Topological effects cause breakdown of bulk-edge correspondence in these systems.

Reciprocal platforms with P-T-D symmetry can also support similar energy sinks.

Abstract

It was recently highlighted that nonreciprocal surface waves can be stopped in suitably designed waveguides, leading to the formation of hotspots wherein the electromagnetic fields are massively enhanced. Here, we prove that this phenomenon has a topological origin and is related to a breakdown of the bulk-edge correspondence in electromagnetic continua with no spatial cut-off. Our theoretical analysis shows that nonreciprocal electromagnetic continua can used to realize energy sinks with ultra-singular fields that absorb all the energy generated in their surroundings. Moreover, it is proven that similar energy sinks may be formed in fully reciprocal optical platforms with a parity-time-duality (P-T-D) symmetry.