Photonic molecules and sensors based on coupling between whispering gallery modes in microspheres

Abstract

Based on analogy between quantum mechanics and the classical electrodynamics, we sorted dielectric microspheres with almost identical positions of their whispering gallery mode (WGM) resonances as photonic atoms. Such microspheres were assembled in a wide range of structures including linear chains and planar photonic molecules. We studied WGM hybridization effects in such structures using side coupling by tapered microfibers as well as finite difference time domain modeling. We demonstrated potential sensing functionality as well as new ways of controlling WGM coupling constants in such molecules. Excellent agreement was found between measured and calculated fiber-transmission spectra for different molecules.