Jul 17 – 22, 2022
Royal Conservatory of Music, Toronto
America/Toronto timezone

Collective Radiative Dynamics of an Ensemble of Cold Atoms Coupled to an Optical Waveguide

Jul 18, 2022, 5:00 PM
1h 30m
Hart House (Hart House)

Hart House

Hart House

7 Hart House Cir, Toronto, ON M5S 3H3
Poster presentation Quantum optics and hybrid quantum systems Poster session


We experimentally and theoretically investigate collective effects in a one-dimensional array of cold atoms coupled to a single-mode optical nanofiber [1]. Our analysis unveils the microscopic (i.e., atom per atom) dynamics of the system, showing that collective interactions gradually build-up along the atomic chain in the direction of propagation of the excitation light pulses. Our theoretical results are supported by time-resolved measurements of the light transmitted and reflected by the atomic ensemble.
In particular, when the excitation pulse is switched off on a time scale much shorter than the atomic lifetime, a superradiant decay is observed in the forward direction, while no speed-up of the decay rate is measured in the backward direction. For longer time scales, our measurements reveal the evolution of the ensemble from the superradiant state to a set of states that are fully subradiant with respect to the fiber mode [2]. Notably, our theoretical model identifies this phenomenon as a key feature of the time evolution of one-dimensional systems prepared in a timed Dicke state. This complex dynamics can be accurately described with a simple analytical expression.
Our results highlight the unique opportunities offered by nanophotonic cold atom systems for the experimental investigation of collective light-matter interaction.

[1] R. Pennetta et al., “Collective Radiative Dynamics of an Ensemble of Cold Atoms Coupled to an Optical Waveguide”, Phys. Rev. Lett., 128, 073601 (2022)

[2] R. Pennetta et al., “Observation of coherent coupling between super- and subradiant states of an ensemble of cold atoms collectively coupled to a single propagating optical mode”, Phys. Rev. Lett. (accepted)

Presenter name Riccardo Pennetta

Primary authors

Dr Riccardo Pennetta (Humboldt University Berlin) Dr Martin Blaha (Humboldt University Berlin) Aisling Johnson (Humboldt University Berlin) Daniel Lechner (Humboldt University Berlin) Dr Philipp Schneeweiss (Humboldt University Berlin) Dr Jürgen Volz (Humboldt University Berlin) Prof. Arno Rauschenbeutel (Humboldt University Berlin)

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