Tunable optical bound states in the continuum beyond in-plane symmetry protection
Abstract
The formation of tunable bound states in the continuum (BICs) within photonic crystal (PC) slabs has been investigated by using a semianalytical coupled-wave theory framework. An analytic expression of the radiative wave has been derived in order to depict the condition of BICs. As a result, in addition to well-known symmetry-protected BICs, a novel type of vertical-cancellation BIC can be realized through continuously varying a given parameter to eliminate radiative waves at the boundaries. We investigated one-dimensional and two-dimensional (2D) periodic structures, and found that such tunable BICs can occur for a wide range of wave vectors by the selection of appropriate slab thicknesses. For a 2D PC slab, a ring of high-Q modes is predicted and confirmed by numerical simulation.
- Publication:
-
Physical Review B
- Pub Date:
- December 2016
- DOI:
- 10.1103/PhysRevB.94.245148
- Bibcode:
- 2016PhRvB..94x5148N