arXiv:physics/0502113 · Physical Review Letters
Precision Measurement of Light Shifts in a Single Trapped Ba+ Ion
Jeff A. Sherman, Timo Koerber, Anna Markhotok, Warren Nagourney, E. Norval Fortson
Abstract
Using a single trapped barium ion we have developed an rf spectroscopy technique to measure the ratio of the off-resonant vector ac Stark effect (or light shift) in the $6{S}_{1/2}$ and $5{D}_{5/2}$ states to 0.1% precision. We find $R={\ensuremath{\Delta}}_{S}/{\ensuremath{\Delta}}_{D}=\ensuremath{-}11.494(13)$ at 514.531 nm where ${\ensuremath{\Delta}}_{S,D}$ are the light shifts of the $m=\ifmmode\pm\else\textpm\fi{}1/2$ splittings due to circularly polarized light. Comparison of this result with an ab initio calculation of $R$ would yield a new test of atomic theory and improve the understanding of atomic structure needed to interpret a proposed atomic parity violation experiment. By appropriately choosing an off-resonant light shift wavelength one can emphasize the contribution of one or a few dipole matrix elements and precisely determine their values.