Erlangen 2022 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 50: Precision spectroscopy of atoms and ions III (joint session A/Q)

Q 50.4: Vortrag

Donnerstag, 17. März 2022, 11:30–11:45, A-H3

Investigation of frequency shifts induced by thermal radiation for an ⁸⁸Sr⁺ optical clock — •Martin Steinel¹, Hu Shao¹, Thomas Lindvall², Melina Filzinger¹, Richard Lange¹, Burghard Lipphardt¹, Tanja Mehlstäubler^{1, 3}, Ekkehard Peik¹, and Nils Huntemann¹ — ¹Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany — ²VTT Technical Research Centre of Finland, National Metrology Institute VTT MIKES, P.O. Box 1000, 02044 VTT, Finland — ³Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany

To realize transition frequencies in optical clocks with high accuracy, a careful investigation of all frequency shifts is required. For most systems operated at room temperature, the AC Stark shift induced by thermal radiation is important. It shows a T⁴-dependence, and is proportional to the differential polarizability of the states. For an ion in a radiofrequency (rf) trap, it is challenging to determine the effective temperature T of blackbody radiation, if the trap assembly is heated by rf-losses. Temperature sensors and infrared cameras can be employed to determine T from FEM simulations. Because of the low thermal conductivity of our trap assembly, we expect large uncertainties from such investigations. Thus, we determine the frequency shift from thermal radiation by measuring the clock transition frequency of a single ⁸⁸Sr⁺ ion at three different trap drive powers using our ¹⁷¹Yb⁺ clock as the reference. Using the known polarizability of ⁸⁸Sr⁺, we find a temperature uncertainty of only 4  K and determine the ratio of the unperturbed transition frequencies with 6 × 10⁻¹⁷ fractional uncertainty.