Observation of white light-induced drift separation of Rb isotopes

Abstract

The observation of the separation of rubidium isotopes by white light-induced drift is reported. A broadband modeless laser with a smooth spectrum is used as a light source. Spectral structure formed by the transport of light through the vapor causes a light-induced drift, pushing the 87Rb and pulling the 85Rb. The separation is measured by spectroscopic isotope analysis. Hyperfine effects are considered and rejected as a possible source of a false separation signal. Also investigated is whether statistical properties of the light beyond the time-averaged intensity could produce a net drift. Although it is found that a net drift is possible even for a flat time-averaged spectrum, this is not expected from the structure of the broadband laser used because the associated time scales are too short. The evidence indicates that the observed separation is due to the predicted white light-induced drift effect.