Bonn 2025 – scientific programme
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A: Fachverband Atomphysik
A 11: Poster – Cold Atoms and Molecules, Matter Waves (joint session Q/A/MO)
A 11.1: Poster
Tuesday, March 11, 2025, 14:00–16:00, Tent
Dephasing of Rydberg excitations in optical traps — •Simon Schroers1, Lukas Ahhlheit1, Daniil Svirskiy1, Nina Stiesdal1, Jan de Haan1, Chris Nill2, Igor Lesanovsky2, Wolfgang Alt1, and Sebastian Hofferberth1 — 1Institut für Angewandte Physik, Universität Bonn — 2Institut für Theoretische Physik, Universität Tübingen
Collective Rydberg-excitations of N atoms by a single photon offer a distinct platform for strong light-matter interaction, due to the enhanced coupling by √N. This allows for instance the creation of Rydberg superatoms, namely an atom cloud smaller than the Rydberg-blockade-volume acting as an effective two level-system strongly coupled to a few-photon driving field.
On this poster we show recent experimental results of how we implement a so-called magic wavelength trap for ground state and Rydberg atoms. The magic trap equalizes the AC Stark shifts for both states, thereby enhancing the ground-to-Rydberg state coherence time. Using photon-storage measurements we demonstrate that the optimal wavelength for such a trap depends on the trap’s geometry, as the almost-free Rydberg electron samples different regions of the trap.
We also show an investigation of Rabi oscillation dephasing between the ground and a collectively excited state of a superatom. Comparing simulations and experimental data we demonstrate that the frequency noise of the excitation lasers plays a significant role in the dephasing and identify the noise regimes that are most crucial for such dephasing.
Keywords: Rydberg atom; Magic wavelength trap; Rabi oscillations; Collective excitation