Berlin 2005 – scientific programme
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Q: Quantenoptik und Photonik
Q 68: Laserspektroskopie II
Q 68.5: Talk
Wednesday, March 9, 2005, 12:00–12:15, HU 2014a
Precision spectroscopy of Al+ using quantum logic. — •Piet O. Schmidt, Till Rosenband, Jeroen Koelemeij, Yohei Kobayashi, Scott A. Diddams, Wayne M. Itano, James C. Bergquist, and D.J. Wineland — National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA
We report on progress towards an optical frequency standard based on the narrow (Δνnat/ν≈ 10−17) 1S0—→ 3P0 transition of a trapped aluminum ion. The lack of an accessible cycling transition for laser cooling and detection in Al+ is overcome using quantum information techniques [1]. Al+ is sympathetically cooled by a simultaneously-trapped, laser-cooled beryllium ion. Be+ also serves to read out the internal state of Al+ by applying an internal state-to-motional state mapping operation on each ion that results in a coherent transfer of the aluminum ion’s internal state onto the beryllium ion, where it is then measured with high efficiency [1]. The coherence of this transfer scheme is demonstrated in a Ramsey experiment involving π/2 pulses on both ions. Using this two-ion technique, we measured the absolute frequencies of several Al+ optical transitions including the clock transition via a femto-second frequency comb referenced to the NIST Cs fountain.
This general technique extends high precision optical spectroscopy to previously inaccessible ion species that may be potential candidates for extremely stable and accurate optical clocks [2].
[1] D. Wineland et.al., in Proc. 6th Symposium on Frequency Standards and Metrology, St. Andrews, Scotland, Sept. 9-14, 2001
[2] H.G. Dehmelt, IEEE Trans. Instr. Meas. IM-31, 83 (1982)