Abstract
We report bound states in the radiation continuum (BICs) in a single infinitely long dielectric rod with periodically stepwise modulated permittivity alternating from to . For in air the rod is equivalent to a stack of dielectric disks with permittivity . Because of rotational and translational symmetries the BICs are classified by orbital angular momentum and the Bloch wave vector directed along the rod. For and the symmetry protected BICs have definite polarization and occur in a wide range of the radius of the rod and the dielectric permittivities. More involved BICs with exist only for a selected radius of the rod at a fixed dielectric constant. The existence of robust Bloch BICs with is demonstrated. Asymptotic limits to a homogeneous rod and to very thin disks are also considered.
8 More- Received 12 April 2017
DOI:https://doi.org/10.1103/PhysRevA.96.013841
©2017 American Physical Society