A Proposal of a Linked Optical Rotor and its Fundamental Characteristics

Abstract

A clockwise rotor and a counterclockwise rotor are linked on the optical axis to control the rotation direction by displacing the trapping position. The optical torque of the linked rotor is analyzed for upward-directed focused laser illumination using a ray optics model, under the condition that laser light is incident to not only the lower surfaces but also the side surfaces of both rotors. The trapping position is estimated to be 1.1 μm up the center plane of an SU-8 double rotor (20 μm diameter, 10 μm thick, 3.3 μm wing width) with a laser power at 200 mW via an objective lens with a numerical aperture of 1.4.