Precise measurements of polarizabilities of cesium nS Rydberg states in an ultra-cold atomic ensemble

We present precise measurements of polarizabilities of cesium nS(1/2) (n= 65-75) Rydberg states by Stark spectroscopies. In experiment, Rydberg atoms are excited via a two-photon scheme of a standard magneto-optical trap and detected by the field ionization technique. The Stark shift is measured by analysing the spectroscopy under an external electric field. The polarizability,alpha, is acquired by fitting the experimental data of Stark shifts with Delta W = -12 alpha E-2. The theoretical model is applied to numerically simulate the Stark map and corresponding level shifts, related deviation between the experimental measurements and calculations are less than 2%. The scaling law of polarizabilities, A.(n*)7+B.(n*)6<i(n* is effective principal quantum number), is attained, that shows a good agreement with the measurements.