Enhancing Electric Fields in High-Index Resonators by Flux Conservation of the Displacement Current Density

TL;DR

This paper presents a new principle based on flux conservation of displacement current density to enhance and localize electric fields in high-index nanophotonic resonators, enabling improved control at the nanoscale.

Contribution

It introduces a general design principle for subwavelength electric field enhancement in dielectric resonators based on flux conservation of displacement current.

Findings

Electric field enhancement achieved through local squeezing of resonator sections.

The principle applies broadly to complex dielectric structures.

Potential for improved nanoscale control of displacement currents.

Abstract

Concentrating light within subwavelength spatial regions is a central topic in nanophotonics. In this letter, we introduce a general principle for the subwavelength localization and enhancement of electric fields in high-index resonators, based on the flux conservation of the displacement current density. We apply this design rule to a ring resonator by locally squeezing its section: since the flux is conserved, the electric field is necessarily enhanced to compensate the reduction of the section area. The introduced principle may constitute an important step toward the control of the displacement current density at the nanoscale, guiding the design of the topology and the geometry of complex dielectric structures.