Lifetime Measurement of Cesium Atoms Using a Cold Rydberg Gas

The lifetimes of nS(1/2) and nD(5/2) (n = 60-83) cesium Rydberg states are measured accurately in a magneto-optical trap using the field ionization technique and analyzed with the existing theoretical model. The room temperature blackbody radiation (BBR) and interaction between Rydberg atoms can enhance the decay rate and reduce the spontaneous lifetime of the given Rydberg atom. The measured lifetime shows a good agreement with the calculation accounting a room temperature BBR at low enough Rydberg atomic density. The dependence of measured lifetime on atomic density shows that the collision and interaction between Rydberg atoms have a large effect on the lifetime at higher Rydberg atomic density. The scaling laws of n(2.55 & PLUSMN;0.02) for nD(5/2) state and n(2.30 & PLUSMN;0.01) for nS(1/2) state within n = 60-83 range are obtained and agreement with the model calculation with a relative deviation less than 3%.