Whispering gallery modes of a triatomic photonic molecule

Abstract

We present the results of numerical simulations of the optical spectra of a photonic molecule comprised of three spherical resonators. Our main goal was to elucidate the effects of the special arrangement of the resonators on the optical spectra of the structure. We found that if the centers of the resonators remained in the same equatorial plane, where the equator is defined by the fundamental mode excited in one of the resonators, the spectra of the system remained relatively insensitive to the deviation from the linear arrangement up to an angle between the lines connecting the centers of the pairs of the resonators of about 110°. For larger angles, the spectra show significant modification consisting of the major spectral peaks splitting and shifting. At the same time, the spectra turned out to be quite sensitive to out-of-plane deviations of the positions of the resonators, even at small angles. Thus, the spectra of photonic molecules can be modified by changing the mutual positions of the constituent resonators, which can be useful in reconfigurable photonic devices.