Dispersive bands of bound states in the continuum

TL;DR

This paper introduces a novel concept of a crystal made of bound states in the continuum (BICs), where an array of BICs form a dispersive miniband through indirect coupling via a common continuum, with potential applications in nanophotonics.

Contribution

It proposes the idea of a BIC crystal with dispersive minibands formed by indirect coupling, a new paradigm in the study of BICs in photonics.

Findings

Demonstrates a chain of optical cavities coupled via a continuum.

Shows formation of a dispersive miniband of BICs.

Illustrates the concept with a CROW-based example.

Abstract

Bound states in the continuum (BICs), i.e. highly-localized modes with energy embedded in the continuum of radiating waves, have provided in the past decade a new paradigm in optics and photonics, especially at the nanoscale, with a range of applications from nano photonics to optical sensing and laser design. Here we introduce the idea of a crystal made of BICs, in which an array of BICs are indirectly coupled via a common continuum of states resulting in a tight-binding dispersive energy miniband embedded in the spectrum of radiating waves. The results are illustrated for a chain of optical cavities side-coupled to a coupled-resonator optical waveguide (CROW) with non-local contact points.