Back and forth transfer and coherent coupling in a cold Rydberg dipole gas
Résumé
Coupling by the resonant dipole-dipole energy transfer between cold cesium Rydberg atoms is investigated using time-resolved narrow-band de-excitation spectroscopy. This technique combines the advantage of efficient Rydberg excitation with high-resolution spectroscopy at variable interaction times. The coherent character of the process is studied by back and forth transfer in the np+np <--> ns+(n+1)s reaction. The evolution of coherence is mostly due to the motion between the atoms induced by the dipole-dipole interaction. Dipole-dipole interaction is observed spectroscopically as avoided level crossing.