Bound States in the Continuum: Stability Against Structural Disorder

We consider the influence of structural disorder on the quality factor (Q-factor) of symmetry-protected bound states in the continuum (BIC). Two types of dielectric structures are considered: a bilayer resonator consisting of dielectric rods, and a other one consisting of one layer dielectric blocks. The results show that in bilayer resonator the symmetry-protected bound states in the continuum are more resistant to fluctuations in the distance between the layers. When structural disorder is introduced, the Q-factor of BIC decreases quadratically in both a bilayer and a one layer resonators. With an increase in the degree of disorder, the localization of the electromagnetic field is observed, which leads to a decrease in the effective length of the resonator in all cases.