We found that the Mie scattering distinguishes the topological charge of light beams with phase dislocations. We experimentally and numerically studied the scattering of highly focused Laguerre-Gaussian beams by dielectric and metal spheres, and showed that the scattered field is sensitive to the modulus and to the sign of the topological charge. These findings have implications for position detection of microbubbles using Laguerre-Gaussian beams, and for quantum computing.

V. Garbin, G. Volpe, E. Ferrari, M. Versluis, D. Cojoc, D. Petrov, New Journal of Physics 11, 013046 (2009)