Measurement of the Hyperfine Quenching Rate of the Clock Transition in ${}^{171}$Yb

Abstract

We report the first experimental determination of the hyperfine quenching rate of the $6s^2{}^1{S}_0(F=1/2)-6s6p{}^3{P}_0(F=1/2)$ transition in ${}^{171}$Yb with nuclear spin $I=1/2$. This rate determines the natural linewidth and the Rabi frequency of the clock transition of a Yb optical frequency standard. Our technique involves spectrally resolved fluorescence decay measurements of the lowest lying ${}^3{P}_{0,1}$ levels of neutral Yb atoms embedded in a solid Ne matrix. The solid Ne provides a simple way to trap a large number of atoms as well as an efficient mechanism for populating ${}^3{P}_0$. The decay rates in solid Ne are modified by medium effects including the index-of-refraction dependence. We find the ${}^3{P}_0$ hyperfine quenching rate to be $(4.42\pm 0.35)\times 10^{-2}{\mathrm{s}}^{-1}$ for free ${}^{171}$Yb, which agrees with recent ab initio calculations.

5 pages, 4 figures