Quasi-Bound States in the Continuum in a Finite Chain of Dielectric Scatterers: Theory and Experiment

In this work we experimentally observe a symmetry protected optical bound state in the continuum (BIC)with zero angular momentum in 1D array of ceramic disks at GHz frequencies. We analyze the dependence of Q factor of BIC on the number of the disks and the level of the material losses. We confirmed theoretical prediction about quadratic growth of the Q factor with the number of the disks and its following saturation due to material losses.