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Quantum technologies

Dieter Meschede's research group
Home Group members Deepak Pandey
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Group members
Dr. Deepak Pandey
Contact
Position: Postdoc
Field of research: Fibre cavity QED
Address:
Institut für Angewandte Physik
Wegelerstr. 8
D-53115 Bonn
Germany
Office room: 114
Laboratory room: 219
E-mail: This e-mail address is being protected from spam bots, you need JavaScript enabled to view it.
Office: +49 228 73-6580
Laboratory: +49 228 73-3485
Fax: +49 228 73-3474
 

Publications

  • E. Uruñuela, W. Alt, E. Keiler, D. Meschede, D. Pandey, H. Pfeifer and T. Macha
    Ground-State Cooling of a Single Atom in a High-Bandwidth Cavity, (2019)arXivBibTeX
    ABSTRACT »

    We report on vibrational ground-state cooling of a single neutral atom coupled to a high-bandwidth Fabry-Pérot cavity. The cooling process relies on degenerate Raman sideband transitions driven by dipole trap beams, which confine the atoms in three dimensions. We infer a one-dimensional motional ground state population close to 90% by means of Raman spectroscopy. Moreover, lifetime measurements of a cavity-coupled atom exceeding 40 s imply three-dimensional cooling of the atomic motion, which makes this resource-efficient technique particularly interesting for cavity experiments with limited optical acces.

  • T. Macha, E. Uruñuela, W. Alt, M. Ammenwerth, D. Pandey, H. Pfeifer and D. Meschede
    Non-adiabatic Storage of Short Light Pulses in an Atom-Cavity System, (2019)arXivBibTeX
    ABSTRACT »

    We demonstrate the storage of 5 ns light pulses in a single rubidium atom coupled to a fiber-based optical resonator. Our storage protocol addresses a regime beyond the conventional adiabatic limit and approaches the theoretical bandwidth limit. We extract the optimal control laser pulse properties from a numerical simulation of our system and measure storage efficiencies of (8.2±0.6)%, in close agreement with the maximum expected efficiency. Such well-controlled and high-bandwidth atom-photon interfaces are key components for future hybrid quantum networks.

  • J. Gallego, W. Alt, T. Macha, M. Martinez-Dorantes, D. Pandey and D. Meschede
    Strong Purcell effect on a neutral atom trapped in an open fiber cavity, Phys. Rev. Lett. 121, 17360 (2018)arXivBibTeXPDF
    ABSTRACT »

    We observe a sixfold Purcell broadening of the D2 line of an optically trapped 87Rb atom strongly coupled to a fiber cavity. Under external illumination by a near-resonant laser, up to 90% of the atom's fluorescence is emitted into the resonant cavity mode. The sub-Poissonian statistics of the cavity output and the Purcell enhancement of the atomic decay rate are confirmed by the observation of a strongly narrowed antibunching dip in the photon autocorrelation function. The photon leakage through the higher-transmission mirror of the single-sided resonator is the dominant contribution to the field decay (κ≈2π×50 MHz), thus offering a high-bandwidth, fiber-coupled channel for photonic interfaces such as quantum memories and single-photon sources.


Colloquia