High-Q resonant modes in a finite array of dielectric particles

Bulgakov, Evgeny N.; Sadreev, Almas F. Source: PHYSICAL REVIEW A, 99 (3):10.1103/PhysRevA.99.033851 MAR 26 2019

We trace the Q factor of the resonant modes which are limited to bound states in the continuum (BICs) for N= in the finite array of N dielectric spheres and disks. For the symmetry-protected BICs we observe the quadratic dependence of the Q factor on N for high-refractive-index particles, while for low-refractive-index particles there is an interplay between the quadratic and cubic dependencies. The Q factor of accidental BICs grows cubically with N. We show that a plane wave can excite these quasi-BICs for tuning of the angle of incidence.