Manipulation and precise control of colloidal microsphere resonators coupled to a non-planar waveguide

Abstract

A new operation scheme using optoelectronic tweezers and a locally confined dielectrophoresis to implement a tunable microsphere resonator coupled to a non-planar waveguide is presented. The optoelectronic tweezers are utilized to bring the microsphere to the waveguide while the dielectrophoretic force around the waveguide is exploited to finely tune the gap space between the microsphere and the waveguide in a liquid medium. Through these two mechanisms, we demonstrate a polyester microsphere can be freely moved to an SU-8 rib waveguide and operated in any of the coupling conditions by adjusting applied voltage.