2019/07/22 by Anton I. Ovcharenko, A. I. Ovcharenko, Cédric Blanchard +2 · 1 citation
Engineering · Materials Science · Mathematics · Physics and Astronomy · #Bloch wave #Condensed matter physics #Geometry #Mathematics #Optical Coatings and Gratings #Optics #Photonic Crystals and Applications #Photonic and Optical Devices #Photonic crystal #Physics #Slab #Symmetry (geometry) #physics.optics
paper · pdf · doi:10.1103/physrevb.101.155303
published as Phys. Rev. B 101, 155303 (2020)
arxiv created 2019/07/22 · openalex created_date 2019/07/30 · openalex publication_date 2020/04/10 · arxiv updated 2020/04/15 · openalex updated_date 2026/08/05
We develop a semianalytical model to describe bound states in the continuum (BICs) in photonic crystal slabs. We model leaky modes supported by photonic crystal slabs as a transverse Fabry-Perot resonance composed of a few propagative Bloch waves bouncing back and forth vertically inside the slab. This multimode Fabry-Perot model accurately predicts the existence of BICs and their positions in the parameter space. We show that, regardless of the slab thickness, BICs cannot exist below a cutoff frequency, which is related to the existence of the second-order Bloch wave in the photonic crystal. Thanks to the semianalyticity of the model, we investigate the dynamics of BICs with the slab thickness in symmetric and asymmetric photonic crystal slabs. We evidence that, as the horizontal mirror symmetry is broken, the symmetry-protected BICs that exist in symmetric structures at the \mathrm\ensuremathΓ point of the dispersion diagram become resonance-trapped BICs, but only for specific values of the slab thickness.