A series of avoided crossings of resonances in the system of several different dielectric resonators results in giant Q-factors

Abstract

We perform optimization of Q-factor in the system of freestanding three/four/five/six coaxial subwavelength dielectric disks over all scales. Each parameter contributes almost one order of magnitude of the Q-factor due to multiple avoided crossings of resonances to give totally the unprecedented values for the Q-factors: $6.6\cdot10^4$ for the three, $4.8\cdot10^6$ for four, $8.5\cdot10^7$ for five and one billion for six freestanding silicon disks. By multipole analysis of the resulting hybridized resonant mode we observe that such extremely large values of the $Q$-factor are attributed to strong redistribution of radiation that originates from almost exact destructive interference of dominating complex multipole radiation amplitudes.