Hyperfine coupling constants of the cesium $7D_{5/2}$ state measured up to the octupole term

TL;DR

This paper precisely measures hyperfine coupling constants of cesium's 7D_{5/2} state, improving accuracy over previous data and setting bounds on the magnetic octupole constant, with implications for optical frequency standards.

Contribution

The study provides highly precise measurements of hyperfine constants and bounds on the octupole term for cesium's 7D_{5/2} state, enhancing understanding of atomic interactions.

Findings

Hyperfine constants A and B measured with over 20-fold improved precision.

Bounds established on the magnetic octupole coupling constant C.

Additional measurements of ac Stark shift, collisional shift, and pressure broadening.

Abstract

We report the measurement of the hyperfine splitting in the $7D_{5/2}$ state of $^{133}$Cs using high resolution Doppler-free two-photon spectroscopy enabled by precise frequency scans using an acousto-optic modulator. All the six hyperfine levels are resolved in our spectra. We determine the hyperfine coupling constants A = -1.70867(62) MHz and B = 0.050(14) MHz which represent over 20-times improvement in the precision of both A and B. Moreover, our measurement is sufficiently precise to put bounds on the value of the magnetic octupole coupling constant C = 0.4(1.4) kHz for the $7D_{5/2}$ state. We additionally report the measurement of ac Stark shift [-46 $\pm$ 4 Hz/(W/cm$^2$)], collisional shift and pressure broadening which are important for optical frequency standards based on the $6S_{1/2} \rightarrow 7D_{5/2}$ two-photon transition.