Bound states in the continuum in dielectric waveguides of finite size

Abstract

We study bound states in the continuum related supercavity modes in finite lattices of silicon rods. Two low-frequency symmetry-protected modes are examined. We find that Q factor has almost cubic dependence on the rod number and 50 rods are enough for Q exceeds 104. We discuss possible applications of these supercavity modes based on their electromagnetic field pattern. The structure surrounded by liquid media keeps its functionality by substitution silicon rods with rods made of Ge-Sb-Te.