Open AccessPolarization-independent toroidal dipole resonances driven by symmetry-protected BIC in ultraviolet region
Author(s) -
Xinfeng Wang,
Shiyu Li,
Chaobiao Zhou
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.389469
Subject(s) - polarization (electrochemistry) , physics , dipole , toroid , nanophotonics , optics , resonator , ultraviolet , symmetry breaking , plane wave , dielectric , circular polarization , optoelectronics , quantum mechanics , chemistry , plasma , microstrip
Optical resonances have gained great attention in nanophotonics attributing to their large enhancement of local field. In this work, we investigate polarization-independent toroidal dipole responses governed by bound state in the continuum (BIC) in the ultraviolet region. By introducing symmetry breaking, an asymmetric dielectric nanohole array is employed to excite two symmetry-protected BICs. Far-field contribution and near-field analysis are performed to demonstrate the dominant role of toroidal dipole in the above two modes. Our design shows the same responses under incident plane wave with different polarizations. The calculated enhancement factors also validate that these resonances can produce strong local field enhancement. Our work may provide a route towards resonators with polarization-independent responses and good performance.