Angular Control of Anisotropy-Induced Bound States in the Continuum

TL;DR

This paper investigates how anisotropic waveguide parameters influence the angular directions of bound states in the continuum, enabling their use in filtering and sensing applications.

Contribution

It introduces a method to control the angular loci of bound states in anisotropic waveguides by varying design parameters, expanding their practical utility.

Findings

Bound states can be achieved over a broad range of angles and wavelengths.

Angular loci of bound states are highly sensitive to waveguide parameters.

Potential applications in optical filtering and sensing are demonstrated.

Abstract

Radiation of leaky modes existing in anisotropic waveguides can be cancelled by destructive interference at special propagation directions relative to the optical axis orientation, resulting in fully bound states surrounded by radiative modes. Here we study the variation of the loci of such special directions in terms of the waveguide constitutive parameters. We show that the angular loci of the bound states is sensitive to several design parameters, allowing bound states to exist for a broad range of angular directions and wavelengths and suggesting applications in filtering and sensing.