Realization of tunable microsphere resonators suspended in liquid via dielectrophoretic force

Abstract

A new control mechanism to realize tunable microsphere resonators suspended in liquid is proposed. Via adjusting the bias voltage across an inhomogeneous dielectric structure (a rib waveguide plus microsphere), the microsphere resonator is attracted and levitated on top of the single-mode rib waveguide via an repulsive dielectrophoretic (DEP) force, where the coupling gap between the microsphere resonator and the waveguide is precisely controlled. The tunable gap spacing is analyzed by calculating the dielectrophoretic force through Maxwell stress tensor.