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Q: Fachverband Quantenoptik und Photonik

Q 41: Precision Measurement and Metrology 1

Q 41.1: Vortrag

Mittwoch, 16. März 2011, 16:30–16:45, HÜL 386

Frequency standard based on the octupole transition in ¹⁷¹Yb⁺ — •Nils Huntemann, Maxim Okhapkin, Burghard Lipphard, Stefan Weyers, Christian Tamm, and Ekkehard Peik — Fachbereich Zeit und Frequenz, Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

We present our results on the development of a new optical frequency standard based on the electric octupole (E3) transition ²S_1/2(F=0) → ²F_7/2(F=3) of a single trapped laser-cooled ¹⁷¹Yb⁺ ion at 467 nm.

In comparison with a previously realized optical frequency standard in ¹⁷¹Yb⁺ [Tamm et al., Phys. Rev. A 80 043403 (2009)] this E3 transition benefits from smaller systematic level shifts due to external fields and its negligible natural linewidth. Another important aspect of the new standard is its strong dependence on variations of the fine structure constant α.

A recently built probe laser system [Sherstov et al., Phys. Rev. A 81 021805(R) (2010)] and the use of a new efficient repump scheme allows to observe Fourier transform-limited linewidths below 7 Hz and a resonant excitation probability of more than 90 %.

We lock the probe laser frequency to the resonance signal of the E3 transition and use a real-time extrapolation scheme to eliminate the huge light shift induced by the probe field. The unperturbed transition frequency was measured by a comparison to a caesium fountain clock using a frequency comb generator. The resulting uncertainty was mainly limited by the systematic uncertainty of the fountain clock.