Observation of Resonances in the Radiation Pressure on Dielectric Spheres

We report an experimental check of the Mie-Debye theory for the variation of radiation pressure on dielectric spheres with wavelength and size using optical-levitation techniques. Sharp resonances are observed which are shown to be related to dielectric surface waves. They permit particle-size measurement to a precision of 1 part in ${10}^5$ to ${10}^6$.