Extended Bound states In the Continuum for ultraheavy photons in photonic lattice
Abstract
Here we report on the dispersion engineering of both real and imaginary parts of photonic resonances in photonic crystal via vertical symmetry breaking. Breaking the vertical mirror symmetry of a photonic crystal slab induces a coupling between two leaky resonances of opposite parities. Such hybridization acts on both the real part (i.e. frequency) and the imaginary part (i.e. radiative loss) of Bloch resonances and offers a tailoring of photonic effective mass and creation of Bound states In the Continuum (BICs). In most configurations, the photonic band of interest exhibits two types of BICs: one at the center of the Brillouin zone and one at oblique angle. The first BIC is a symmetryprotected BIC while the second one is a quasiBIC induced by vertical symmetrybreaking. The overlap of two BICs in the momentum space engenders a large area of ultrahigh quality factor around the $\Gamma$ point, called extended BIC. All numerical results are nicely reproduced by an intuitive analytical model, combining diffractive and symmetrybreaking couplings. Our results propose an unique scheme to study localizedBIC in photonic lattice: ultraheavy photons with infinite lifetime along a broad range of momentum.
 Publication:

arXiv eprints
 Pub Date:
 May 2019
 arXiv:
 arXiv:1905.00215
 Bibcode:
 2019arXiv190500215L
 Keywords:

 Physics  Optics
 EPrint:
 8 pages, 5 figures