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A: Fachverband Atomphysik
A 12: Poster I
A 12.30: Poster
Tuesday, March 7, 2023, 16:30–19:00, Empore Lichthof
Towards a compound 27Al - 40Ca and multi-ion 40Ca clock — •Lennart Pelzer1, Johannes Kramer1,2, Kai Dietze1,2, Fabian Dawel1,2, Marek Hild1,2, Victor Martinez-Lahuerta2, Klemens Hammerer2, and Piet O. Schmidt1,2 — 1Physikalisch-Technische Bundesanstalt, 38116 Braunschweig — 2Leibniz Universität Hannover, 30167 Hannover
Optical atomic clocks based on a single aluminium ion reach a record fractional frequency systematic uncertainty below 10−18. This outstanding precision allows for applications like relativistic geodesy on the cm-level and helps to tighten the bounds for physics beyond the standard model. But single ion clocks are impeded by their low signal-to-noise ratio and require therefore long averaging times. Even state-of-the-art laser stabilization is not sufficient to enable lifetime-limited interrogation of 27Al+. Thus, pre-stabilization of the clock laser via a 40Ca+ multi-ion reference could further improve the coherence time of the laser and thus increase the interrogation time on 27Al+. Here we present the status of PTB’s 27Al+ clock and the implementation of a multi-ion Ca+ reference based on dynamical decoupling. The estimated error budget of 1 × 10−18 of the 27Al+ clock is based on measurements using a 40Ca+ ion as a sensor. A continuous dynamic decoupling scheme is used to suppress inhomogeneous broadening from quadrupole and tensor ac Stark shifts in multi-ion 40Ca+ crystals. Simultaneous suppression of first order Zeeman shifts allows interrogation of the crystal close to its natural lifetime limit.