Measurement of the Hyperfine Quenching Rate of the Clock Transition in ¹⁷¹Yb

Original · EN

We report the first experimental determination of the hyperfine quenching rate of the 6s²¹S₀(F=1/2) - 6s6p³P₀(F=1/2) transition in ¹⁷¹Yb 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 ³P₀,₁ 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 ³P₀. The decay rates in solid Ne are modified by medium effects including the index-of-refraction dependence. We find the ³P₀ hyperfine quenching rate to be (4.42±0.35)×10⁻²s⁻¹ for free ¹⁷¹Yb, which agrees with recent ab initio calculations.