Erlangen 2022 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 24: Quantum Effects
Q 24.7: Poster
Dienstag, 15. März 2022, 16:30–18:30, P
Light-matter interaction at the transition from single-mode to multimode cavity QED — •Daniel Lechner, Riccardo Pennetta, Martin Blaha, Philipp Schneeweiss, Jürgen Volz, and Arno Rauschenbeutel — Humboldt Universität zu Berlin, Institut für Physik, Newtonstr. 15, 12489 Berlin, Germany
Cavity QED is conventionally described by the Tavis-Cummings model, where quantum emitters strongly couple to a single-mode cavity. This description implicitly assumes that the cavity roundtrip time, trt, is by far the smallest timescale of the system and, in particular, much smaller than the lifetime, τ, of the quantum emitters. Here, we present an experiment in which this condition is progressively not fulfilled. The setup consists of a fiber ring-resonator with variable length, coupled to cold cesium atoms via an optical nanofiber. Consequently, we can explore the transition from a regime close to single-mode cavity QED to multimode cavity QED with resonator lengths of 5.8 m (trt ≈ τ) and 45.5 m (trt ≫ τ). We record the response of the atom–cavity system after the sudden switch-on of resonant laser light. For the 5.8-m resonator, on top of the conventional Rabi oscillations, we observe the appearance of sharp features at multiples of the roundtrip time. For the 45.5-m long cavity, due to coupling to many resonator modes, the Rabi oscillations disappear and only the response of the atomic ensemble after each individual roundtrip remains. Our observations shed light on the interplay between the single-pass collective response of the atoms to the propagating cavity field and the ensemble–cavity dynamics.