Enhanced Directional Coupling of Light with a Whispering Gallery Microcavity

TL;DR

This paper demonstrates a significant enhancement in directional light coupling between nanowaveguides using a whispering gallery microcavity, leveraging spin-orbit interaction effects to improve efficiency in nanophotonic circuits.

Contribution

It introduces an experimental method to enhance directional coupling in nanophotonics using whispering gallery microcavities, applicable to both TM and TE modes.

Findings

Achieved an order of magnitude increase in coupling efficiency.

Validated enhancement for both TM and TE modes.

Provides a practical approach for efficient light routing in nanophotonics.

Abstract

Directional coupling of light in nanophotonic circuits has recently attracted increasing interest, with numerous experimental realizations based on broken rotational or mirror symmetries of the light-matter system. The most prominent underlying effect is the spin-orbit interaction of light in subwavelength structures. Unfortunately, coupling of light to such structures is, in general, very inefficient. In this work, we experimentally demonstrate an order of magnitude enhancement of the directional coupling between two nanowaveguides by means of a whispering gallery microcavity. We also show that both transversmagnetic and transverse electric modes can be used for the enhancement.