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arXiv · 1907.01446

A Topology-Controlled Photonic Cavity Based on the Near-Conservation of the Valley Degree of Freedom

Yandong Li·Yang Yu·Fengyu Liu·Baile Zhang·Gennady Shvets
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Abstract

We demonstrate a novel path to localizing topologically-nontrivial photonic edge modes along their propagation direction. Our approach is based on the near-conservation of the photonic valley degree of freedom associated with valley-polarized edge states. When the edge state is reflected from a judiciously oriented mirror, its optical energy is localized at the mirror surface because of an extended time delay required for valley-index-flipping. The degree of energy localization at the resulting topology-controlled photonic cavity (TCPC) is determined by the valley-flipping time, which is in turn controlled by the geometry of the mirror. Intuitive analytic descriptions of the "leaky" and closed TCPCs are presented, and two specific designs--one for the microwave and the other for the optical spectral ranges--are proposed.

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Yandong Li, Yang Yu, Fengyu Liu, Baile Zhang, Gennady Shvets. 2019-07-02. A Topology-Controlled Photonic Cavity Based on the Near-Conservation of the Valley Degree of Freedom. https://doi.org/10.1103/physrevlett.125.213902

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