Stark-inducedL-mixing interferences in ultracold cesium Rydberg atoms

The $l$-mixing effect and state-transfer induced by an external electric field pulse in ultracold Rydberg gases are observed with cesium atoms excited to $\mathit{nS}$ states, and measured with a state selective field ionization technique. High-$l$ states are populated from the initially excited $\mathit{nS}$ states due to non-adiabatic transitions through avoided crossings that are formed between the $\mathit{nS}$ state and the ($n\ensuremath{-}4$) manifold. The population of the product state is investigated as a function of the electric field pulse parameters. The coherent property of the transfer is demonstrated using a 2-pulse sequence and the results are consistent with the theoretical calculations. This $l$-mixing phenomenon in the electric field may be used to help forming a molecular potential and create Rydberg molecules.