Guiding light through quasi-TE modes embedded in the radiation continuum

TL;DR

This paper presents a novel bound state in the continuum (BIC) in coupled waveguides, enabling guiding of quasi-TE modes in lower-index cores through structural tuning.

Contribution

It introduces a new BIC mechanism in coupled waveguides that allows guiding of quasi-TE modes in lower-index cores, differing from previous configurations.

Findings

BIC appears when coupling is suppressed by structural tuning.

Genuine guiding of quasi-TE modes in lower-index cores is achieved.

The scheme offers a new way to control light in photonic structures.

Abstract

We introduce a new type of a bound state in the continuum (BIC) which appears in the photonic structure consisting of two coupled waveguides where one of them supports a discrete eigenmode spectrum embedded in the continuum of the other one. A BIC appears when the coupling is suppressed by suitable tuning of structural parameters. In contrast to the previously described configurations, our scheme facilitates genuine guiding of quasi-TE modes in the core with the lower refractive index.