Q/V enhancement of Si micropillar resonator with Bragg reflectors in BIC regime

Abstract

Recent progress in nanophotonics is increasingly aimed at the use of fully dielectric nanoparticles that support magnetic and electric Mie resonances, but as the Mi theory predicts, dielectric subwavelength resonators have extremely low Q-values. However it has been shown that using so-called bound states in the continuum (BIC) allows to achieve high values of Q for high index cylindrical resonator. Here we show that the use distributed Bragg reflectors in regime of BIC allows to drastically increase the absolute values of quality factors, and what is even more important quality factor to mode volume ratio, the quantity proportional to the Purcell factor which is of the immense importance for triggering nonlinear optical processes in nanophotonic devices.