Abstract
We report on the observation of ultralong range interactions in a gas of cold rubidium Rydberg atoms. The van der Waals interaction between a pair of Rydberg atoms separated as far as 100 000 Bohr radii features two important effects: spectral broadening of the resonance lines and suppression of excitation with increasing density. The density dependence of these effects is investigated in detail for the - and -Rydberg states with principal quantum numbers and excited by narrow-band continuous-wave laser light. The density-dependent suppression of excitation can be interpreted as the onset of an interaction-induced local blockade.
- Received 15 April 2004
DOI:https://doi.org/10.1103/PhysRevLett.93.163001
©2004 American Physical Society