Measurement of the radial matrix elements of the $6s \: ^2S_{1/2} \rightarrow 7p \: ^2P_{J} $ transitions in atomic cesium

Abstract

We report measurements of the absorption strength of the cesium $6s \: ^2S_{1/2} \rightarrow 7p \: ^2P_{3/2} $ and the $6s \: ^2S_{1/2} \rightarrow 7p \: ^2P_{1/2} $ transitions at $λ= 456$ nm and 459 nm, respectively, in an atomic vapor cell. By simultaneously measuring the absorption strength on the Cs D$_1$ line ($6s \: ^2S_{1/2} \rightarrow 6p \: ^2P_{1/2} $), for which the electric dipole transition moment is precisely known, we are able to determine the reduced dipole matrix elements for these two lines. We report $\langle 7P_{3/2} || r || 6S_{1/2} \rangle = 0.5780 \: (7) \: a_0$ and $\langle 7P_{1/2} || r || 6S_{1/2} \rangle = 0.2789 \: (16) \: a_0$, with fractional uncertainties of 0.12% and 0.6%, respectively. Through these measurements, we can reduce the discrepancy between values of the tensor polarizability for the Cs $6s \: ^2S_{1/2} \rightarrow 7s \: ^2S_{1/2} $ transition that have been determined through two different methods.