Realization of Topology-controlled Photonic Cavities in a Valley Photonic Crystal

TL;DR

This paper demonstrates the experimental creation of topology-controlled photonic cavities in valley photonic crystals, utilizing mirror orientation to localize valley-polarized edge states, with energy confinement and quality factors governed by valley-flipping time.

Contribution

It introduces a novel method to control photonic cavity properties through mirror topology in valley photonic crystals, expanding the design possibilities for topological photonics.

Findings

Strong electromagnetic confinement observed at mirror surfaces.

Energy localization and quality factors depend on valley-flipping time.

Experimental validation of topology-controlled cavity behavior.

Abstract

We report an experimental realization of a new type of topology-controlled photonic cavities in valley photonic crystals by adopting judiciously oriented mirrors to localize the valley-polarized edge states along their propagation path. By using microwave frequency- and time-domain measurements, we directly observe the strong confinement of electromagnetic energy at the mirror surface due to the extended time delay required for the valley index flipping. Moreover, we experimentally demonstrate that both the degree of energy localization and quality factors of the topology-controlled photonic cavities are determined by the valley-flipping time which is controlled by the topology of the mirror. These results extend and complement the current design paradigm of topological photonic cavities.