Manipulating the supermodes in photonic molecules: prospects for all-optical switching and sensing

Abstract

A specific photonic structure, a photonic molecule (PM), formed by several ordered resonance microcavities (photonic atoms) supporting high-quality “whispering gallery” eigenmodes (WGMs) is considered theoretically. All PM atoms are bound together by WGM electromagnetic fields and constitute collective supermodes (SMs) of the whole molecule. Usually, the composition of the SM spectrum in a particular PM is determined only by its topology (atomic lattice type, interatomic gap). We propose another way to control the spectral composition of supermodes by using bilateral (double-sided) optical pumping of a PM provided by a variable phase shift between the optical excitation channels. We show that multiatomic PMs made of silicon microcylinders demonstrate more than tenfold amplification/suppression of particular supermode intensity located in the Stokes/anti-Stokes wing of the molecular spectrum. This may be beneficial for the engineering of PM-based intensity-dependent sensors of refractive index changes in optical pumping buses or an all-optical thyristor with high switching range.