[OPTICAL REVIEW Vol. 4, No. 4 (1997) 447-449]

Theoretical Demonstration of a Newly Designed Micro-Rotator Driven by Optical Pressure on a Light Incident Surface

Hiroo UKITA and Kenji NAGATOMI

Faculty of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga, 525 Japan

(Received February 7, 1997; Accepted April 28, 1997)

A newly designed cylindrical optical micro-rotator which has slopes for trapping and rotation on its upper surface is proposed. The cylindrical shape is effective in decreasing viscous drag force (damping factor) in the medium. A ray-tracing method considering the beam waist is employed to analyze the radiation pressure exerted on the upper surface of the rotator. We have demonstrated optical trapping and high speed rotation for various optical beam parameters such as the lens numerical aperture and the Gaussian mode profile as well as rotator shape parameters including oblique angle, height and diameter.

Key words : optical micro-rotator, cylindrical rotator, optical torque, optical tweezers, ray-tracing, viscosity