Light-force technique for measuring polarizabilities

We have developed a light-force technique for measuring polarizabilities. This new method uses the polarizaton forces experienced by an atom in the intense, inhomogeneous electric field of a standing-wave laser to deduce the polarizability. Using a Nd:YAG laser at ${\lambda }_{\mathrm{SW}}$=1.064 μm for the light force, we measured the polarizability of rubidium at this wavelength to be α(${\mathrm{\omega }}_{\mathrm{SW}}$)=114±9 A${\mathrm{̊}}^3$ (σ). Conversion of this ac polarizability to a static value using a semiempirical formula gives a value of ${\mathrm{\alpha }}_{\mathrm{dc}}$=52 A${\mathrm{̊}}^3$, within 10% of the best published experimental results.