Controlling Directionality and Dimensionality of Wave Propagation through Separable Bound States in the Continuum

TL;DR

This paper develops a general framework for creating and controlling bound states in the continuum (BICs) in various wave systems, enabling reconfigurable wave storage, directional emission, and dimensional confinement switching.

Contribution

It introduces a universal condition for BIC formation from wave equation separability and demonstrates control over their radiation patterns through symmetry perturbations.

Findings

New BIC examples in optical, atomic, and electronic models.

Reconfigurable radiation patterns for wave storage and release.

Control over wave confinement dimensionality.

Abstract

A bound state in the continuum (BIC) is an unusual localized state that is embedded in a continuum of extended states. Here, we present the general condition for BICs to arise from wave equation separability and show that the directionality and dimensionality of their resonant radiation can be controlled by exploiting perturbations of certain symmetry. Using this general framework, we construct new examples of separable BICs in realistic models of optical potentials for ultracold atoms, photonic systems, and systems described by tight binding. Such BICs with easily reconfigurable radiation patterns allow for applications such as the storage and release of waves at a controllable rate and direction, systems that switch between different dimensions of confinement, and experimental realizations in atomic, optical, and electronic systems.