Optically Induced Rotation of Combined Mie Particles within an Evanescent Field of a Gaussian Beam

Abstract
We demonstrate a windmill type rotation of combined Mie particles caused by optical forces of the evanescent field generated at the surface of a Gadolinium Gallium Garnet prism where a linearly polarized Nd:YAG laser beam (of wavelength 532 nm and power 100 mW) is totally reflected. The combined particles such as doublets (or triplets) consisting of polystyrene latex (or yeast) spheres with diameters of 3–5 µm are reported to rotate with angular velocities of 1 rpm in water when the particles are slightly displaced from 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.