On the robustness of bound states in the continuum in waveguides with lateral leakage channels

Abstract

Bound states in the continuum (BICs) are trapped or guided modes with frequencies in radiation continua. They are associated with high-quality-factor resonances that give rise to strong local field enhancement and rapid variations in scattering spectra, and have found many valuable applications. A guided mode of an optical waveguide can also be a BIC, if there is a lateral structure supporting compatible waves propagating in the lateral direction, i.e., there is a channel for lateral leakage. A BIC is typically destroyed (becomes a resonant or a leaky mode) if the structure is slightly perturbed, but some BICs are robust with respect to a large family of perturbations. In this paper, we show (analytically and numerically) that a typical BIC in optical waveguides with a left-right mirror symmetry and a single lateral leakage channel is robust with respect to any structural perturbation that preserves the left-right mirror symmetry. Our study improves the theoretical understanding on BICs and can be useful when applications of BICs in optical waveguides are explored.

arXiv comment10 pages, 4 figures

References in corpus (17)

• Asymmetric metasurfaces with high-$Q$ resonances governed by bound states in the continuum
• Resonantly Trapped Bound State in the Continuum Laser
• Topological nature of bound states in the radiation continuum
• Individual nanoantennas empowered by bound states in the continuum for nonlinear photonics
• Nonradiating Photonics with Resonant Dielectric Nanostructures
• Compact surface Fano states embedded in the continuum of waveguide arrays
• Anisotropy-induced photonic bound states in the continuum
• Bloch bound states in the radiation continuum in a periodic array of dielectric rods
• Refractive index sensing with optical bound states in the continuum
• Experimental observation of symmetry protected bound state in the continuum in a chain of dielectric disks
• Bound states in the continuum and high-Q resonances supported by a dielectric ridge on a slab waveguide
• Ridge Resonance: A new Resonance Phenomenon for Silicon Photonics Harnessing Bound States in the Continuum
• Bound States in the Continuum on Periodic Structures: Perturbation Theory and Robustness
• Bound states in the continuum on periodic structures surrounded by strong resonances
• Perturbation theories for symmetry-protected bound states in the continuum on two-dimensional periodic structures
• Resonant field enhancement near bound states in the continuum on periodic structures
• Conditional robustness of propagating bound states in the continuum on biperiodic structures

Cited by in corpus (3)

• Parametric dependence of bound states in the continuum: a general theory
• How many parameters do we need to obtain a BIC in symmetric and asymmetric structures?
• Frequency perturbation theory of bound states in the continuum in a periodic waveguide