Dynamic polarizability of the $^{85}$Rb $5D_{3/2}$-state in 1064 nm light

Abstract: We report a measurement of the dynamic (ac) scalar polarizability of the $5D_{3/2}$ state in $^{85}$Rb atoms at a laser wavelength of 1064~nm. Contrary to a recent measurement in Phys. Rev. \textbf{A} 104, 063304 (2021), the experiments are performed in a low-intensity regime in which the ac shift is less than the $5D_{3/2}$ state's hyperfine structure, as utilized in numerous experiments with cold, trapped atoms. The extracted ac polarizability is $\alpha_{5D_{3/2}} = -499\pm59$~a.u., within the uncertainty of the aforementioned previous result. The calibration of the 1064~nm light intensity, performed by analyzing light shifts of the D1 line, is the main source of uncertainty. Our results are useful for applications of the Rb $5D_{3/2}$ state in metrology, quantum sensing, and fundamental-physics research on Rydberg atoms and molecules.