Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 59: Ultra-cold atoms, ions, and BEC VII (joint session A/Q)
Q 59.3: Talk
Friday, March 13, 2020, 11:45–12:00, f303
A subradiant two-dimensional atomic array forming an optical mirror — •David Wei1, Jun Rui1, Antonio Rubio-Abadal1, Simon Hollerith1, Kritsana Srakaew1, Simon Evered1, Immanuel Bloch1,2,3, and Christian Gross1 — 1Max-Planck-Institut für Quantenoptik, Garching, Germany — 2Fakultät für Physik, Ludwig-Maximilians-Universität, München, Germany — 3Munich Center for Quantum Science and Technology (MCQST), München, Germany
When quantum emitters are positionally structured on sub-wavelength scales, photon-mediated dipole-dipole interactions can strongly alter the spectral and directional radiative response. Tightly trapped atoms in optical lattices, only coupled to the electromagnetic vacuum, constitute ideal dipolar emitters to study such cooperative behaviour.
In our experiment, we probe the collective properties of a two-dimensional square array of atomic dipoles by performing spectroscopic absorption and reflection measurements. We directly observe considerably subradiant response and demonstrate that the array acts as a reflective mirror formed by a single mono-layer of a few hundred atoms. By varying the atom density within the array, we are able to control the influence of the dipolar interactions. By introducing positional disorder in the atomic ensemble, we analyze the role of the array structure. Its importance is emphasized by dynamically breaking and restoring the order using atomic Bloch oscillations to control the reflectivity of the atomic mirror.