Physical Review Letters
Cs-Based Frequency Measurement of a Single, Trapped Ion Transition in the Visible Region of the Spectrum
J. E. Bernard, Alan A. Madej, L. Marmet, Bradley G. Whitford, Klaus J. Siemsen, S. Cundy
Abstract
An optical frequency chain referenced to a Cs atomic clock has been used to measure directly the frequency of the electric quadrupole allowed $5s^{2}S_{1/2}\ensuremath{-}4d^{2}D_{5/2}$ transition at 445 THz in a single, trapped, and laser cooled ${}^{88}{\mathrm{Sr}}^{+}$ ion. A transition frequency, ${f}_{S\ensuremath{-}D}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}444779044095.4\mathrm{kHz}$ with an estimated standard uncertainty of 0.2 kHz has been determined. Intrinsic offsets of the probed ion transition in the current experiment are calculated to be at the ${10}^{\ensuremath{-}15}$ level.