Determination of the static polarizability of the8sS1∕22state of atomic cesium

Abstract

We report a precise determination of the static polarizability of the $8s^{2}S_{1∕2}$ state of atomic cesium, carried out jointly through experimental measurements of the dc Stark shift of the $6s^{2}S_{1∕2}\ensuremath{\rightarrow}8s^{2}S_{1∕2}$ transition using Doppler-free two-photon absorption and theoretical computations based on a relativistic all-order method. We enhance the precision of the measurement by imposing phase-modulation sidebands on the laser beam and by using a pair of vapor cells, one of which serves as a reference, and measuring the absorption spectrum in each cell with a single scan of the laser frequency. The measured value for the polarizability of the $8s$ state is $38,060\ifmmode\pm\else\textpm\fi{}250{a}_{0}^{3}$, in very good agreement with our theoretical value of $38,260\ifmmode\pm\else\textpm\fi{}290{a}_{0}^{3}$. In addition, the small difference in the Stark shift measurement for the two hyperfine states that we examine yields a variation in the polarizability due to the magnetic dipole contact interaction of $290\ifmmode\pm\else\textpm\fi{}30{a}_{0}^{3}$.