Interaction between coaxial dielectric disks enhances the Q factor

We study the behavior of resonant modes under variation of the distance between two coaxial dielectric disks and show an avoided crossing of resonances because of the interaction between the disks. Owing to coaxial arrangement of disks, the resonant modes are specified by the azimuthal index m=0,1,2,…. In the present paper, we consider the case m=0. At a long enough distance, the modes are symmetric and antisymmetric hybridizations of the resonant modes of the isolated disk. With decreasing the distance, the interaction becomes stronger, giving rise to avoided crossings of different resonances of the isolated disk. This in turn enhances the Q factor of the two disks by one order in magnitude compared to the Q factor of the isolated disk.