Optically induced rotation of combined Mie particles within an evanescent field of a Gaussian beam

We demonstrate a windmill type rotation of combined Mie particles caused by optical forces of the evanescent field generated at the surface of a Gadol inium Gallium Garnet prism where a linearly polarized Nd:YAG laser beam (of wavelength 532 nm and power 100 mW) is totally reflected. The combined par ticles such as doublets (or triplets) consisting of polystyrene latex (or y east) spheres with diameters of 3-5 mu m are reported to rotate with angula r velocities of 1 rpm in water when the particles ale slightly displaced fr om the center of the Gaussian evanescent spot. The particle rotation in the inhomogeneous evanescent fields can be useful for a potential application to micromotors or microaccelerometers.