Bonn 2025 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 12: Poster – Cold Atoms and Molecules, Matter Waves (joint session Q/A/MO)

MO 12.1: Poster

Dienstag, 11. März 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