Measurement of the ratio of the scalar polarizability to the vector polarizability for the $6s ^2S_{1/2} \rightarrow 7s ^2S_{1/2}$ transition in cesium

Abstract

We report measurements of the ratio of the scalar polarizability $\alpha$ to the vector polarizability $\beta$ for the $6s ^2S_{1/2} \rightarrow 7s ^2S_{1/2}$ transition in atomic cesium. These measurements are motivated by a discrepancy between the values of the vector transition polarizability as determined using two separate methods. In the present measurement, we use a two-pathway, coherent-control technique in which we observe the interference between a two-photon interaction driven by infrared light at 1079 nm and a linear Stark-induced interaction driven by the mutually-coherent second harmonic of this infrared beam at 540 nm. The result of our measurements is $\alpha/\beta = -9.902 \: (9)$, in good agreement with the previous determination of this ratio. This measurement, critical to the study of atomic parity violation in cesium, does not reduce the discrepancy between the two methods for the determination of the vector polarizability $\beta$ for this transition.