Robustness of Bound States in the Continuum in Bilayer Structures against Symmetry Breaking

Abstract

We investigate the robustness of bound states in the continuum (BICs) in a bilayer dielectric rod array against geometric and material perturbations. Our analysis focuses on both symmetry-protected and Fabry-Pérot BICs, examining their transformation into quasi-BICs under three structural modifications: (i) in-plane displacement of one layer, which breaks the C${}_2$ symmetry of the system; (ii) introduction of material losses that break time-reversal symmetry; and (iii) variation in the interlayer distance, which preserves structural symmetry. In particular, we demonstrate that material losses inevitably induce radiation in Fabry-Pérot BICs via second-order perturbation processes, converting them into quasi-BICs, while symmetry-protected BICs remain non-radiative. We further show that, despite the inherent instability of BICs under symmetry-breaking effects, their resilience can be significantly enhanced through proper design. Both Fabry-Pérot and symmetry-protected BICs exhibit exponentially weak sensitivity to C${}_2$-breaking perturbations as the interlayer distance increases. Finally, we show that additional FP-BICs emerge under oblique incidence, originating from the interference of two high-Q quasi-BICs near the symmetry-protected ones. Our findings pave the way for the development of BIC-based photonic devices with improved robustness against fabrication imperfections, environmental variations, and material losses.

arXiv comment13 pages, 9 figures

References in corpus (24)

• 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
• Giant nonlinear response at the nanoscale driven by bound states in the continuum
• Bound states in the continuum and Fano resonances in the strong mode coupling regime
• Terahertz sensing of 7nm dielectric film with bound states in the continuum metasurfaces
• Interference traps waves in open system: Bound states in the continuum
• Nonlinear polaritons in monolayer semiconductor coupled to optical bound states in the continuum
• Bloch bound states in the radiation continuum in a periodic array of dielectric rods
• Strong light-matter interaction with self-hybridized bound states in the continuum in monolithic van der Waals metasurfaces
• Strong coupling between excitons in transition metal dichalcogenides and optical bound states in the continuum
• Formation Mechanism of Guided Resonances and Bound States in the Continuum in Photonic Crystal Slabs
• Strongly enhanced light-matter coupling of a monolayer WS2 from a bound state in the continuum
• Bound states in the continuum in symmetric and asymmetric photonic crystal slabs
• Electromagnetic bound states in the radiation continuum for periodic double arrays of subwavelength dielectric cylinders
• Observation of supercavity modes in subwavelength dielectric resonators
• Propagating bound states in the continuum in dielectric gratings
• Room Temperature Exciton-Polariton Condensation in Silicon Metasurfaces Emerging from Bound States in the Continuum
• Enhanced sensitivity of an all-dielectric refractive index sensor with optical bound state in the continuum
• Multipolar theory of bianisotropic response
• Fabry-Perot Bound States in the Continuum in an Anisotropic Photonic Crystal
• Resonant properties of composite structures consisting of several resonant diffraction gratings
• Pumping with Symmetry

Cited by in corpus (1)

• Singular value decomposition to describe bound states in the continuum in periodic metasurfaces