On the simultaneous scattering of two photons by a single two-level atom

Year: 2023

Authors: Masters L., Hu XX., Cordier M., Maron G., Pache L., Rauschenbeutel A., Schemmer M., Volz J.

Autors Affiliation: Humboldt Univ, Dept Phys, Berlin, Germany; Ist Nazl Ott Consiglio Nazl Ric CNR INO, Sesto Fiorentino, Italy.

Abstract: The interaction of light with a single two-level emitter is the most fundamental process in quantum optics, and is key to many quantum applications. As a distinctive feature, two photons are never detected simultaneously in the light scattered by the emitter. This is commonly interpreted by saying that a single two-level quantum emitter can only absorb and emit single photons. However, it has been theoretically proposed that the photon anticorrelations can be thought of as arising from quantum interference between two possible two-photon scattering amplitudes, which one refers to as coherent and incoherent. This picture is in stark contrast to the aforementioned one, in that it assumes that the atom has two different mechanisms at its disposal to scatter two photons at the same time. Here we experimentally validate the interference picture by showing that, when spectrally rejecting only the coherent component of the fluorescence light of a single two-level atom, the remaining light consists of photon pairs that have been simultaneously scattered by the atom. Our results offer fundamental insights into the quantum-mechanical interaction between light and matter and open up novel approaches for the generation of highly non-classical light fields enabling, for example, Fourier-limited photon-pair sources that approach the theoretical limit in brightness. The incoherent component of the fluorescence from a single two-level atom is investigated after rejecting the coherent component. Contrary to intuition, its photon statistics experimentally shows strong photon bunching. This result suggests that the atom does in fact simultaneously scatter two photons.

Journal/Review: NATURE PHOTONICS

Volume: 17 (11)      Pages from: 972  to: +

More Information: We acknowledge funding by the Alexander von Humboldt Foundation in the framework of the Alexander von Humboldt Professorship endowed by the Federal Ministry of Education and Research, as well as the European Commission under project DAALI (no. 899275). X.-X.H. acknowledges a Humboldt Research Fellowship by the Alexander von Humboldt Foundation. M.C. and M.S. acknowledge support by the European Commission (Marie Sklodowska-Curie IF grants nos. 101029304 and 896957).
KeyWords: Resonance Fluorescence; Side-band
DOI: 10.1038/s41566-023-01260-7

ImpactFactor: 32.300
Citations: 7
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-11-03
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