TY - JOUR

T1 - Unraveling Two-Photon Entanglement via the Squeezing Spectrum of Light Traveling through Nanofiber-Coupled Atoms

AU - Hinney, Jakob

AU - Prasad, Adarsh S.

AU - Mahmoodian, Sahand

AU - Hammerer, Klemens

AU - Rauschenbeutel, Arno

AU - Schneeweiss, Philipp

AU - Volz, Jürgen

AU - Schemmer, Max

N1 - Funding Information: We are grateful to A. Sørensen, L. Orozco, P. Solano, J.-H. Mueller, B. Hacker, and M. Kraft for stimulating discussions and helpful comments. We thank S. Rind for his support in building the experiment. We acknowledge financial support by the Alexander von Humboldt Foundation, the European Commission under the projects ErBeStA (No. 800942) and the ERC grant NanoQuaNt, and by the Austrian Science Fund (DK CoQuS Project No. W 1210-N16). M. S. acknowledges support by the European Commission (Marie Skłodowska-Curie IF Grant No. 896957). S. M. and K. H. acknowledge funding from DFG through CRC 1227 DQ-mat, projects A05 and A06, and “Niedersächsisches Vorab” through the “Quantum-and Nano-Metrology (QUANOMET).”

PY - 2021/9/14

Y1 - 2021/9/14

N2 - We observe that a weak guided light field transmitted through an ensemble of atoms coupled to an optical nanofiber exhibits quadrature squeezing. From the measured squeezing spectrum we gain direct access to the phase and amplitude of the energy-time entangled part of the two-photon wavefunction which arises from the strongly correlated transport of photons through the ensemble. For small atomic ensembles we observe a spectrum close to the lineshape of the atomic transition, while sidebands are observed for sufficiently large ensembles, in agreement with our theoretical predictions. Furthermore, we vary the detuning of the probe light with respect to the atomic resonance and infer the phase of the entangled two-photon wavefunction. From the amplitude and the phase of the spectrum, we reconstruct the real- and imaginary part of the time-domain wavefunction. Our characterization of the entangled two-photon component constitutes a diagnostic tool for quantum optics devices.

AB - We observe that a weak guided light field transmitted through an ensemble of atoms coupled to an optical nanofiber exhibits quadrature squeezing. From the measured squeezing spectrum we gain direct access to the phase and amplitude of the energy-time entangled part of the two-photon wavefunction which arises from the strongly correlated transport of photons through the ensemble. For small atomic ensembles we observe a spectrum close to the lineshape of the atomic transition, while sidebands are observed for sufficiently large ensembles, in agreement with our theoretical predictions. Furthermore, we vary the detuning of the probe light with respect to the atomic resonance and infer the phase of the entangled two-photon wavefunction. From the amplitude and the phase of the spectrum, we reconstruct the real- and imaginary part of the time-domain wavefunction. Our characterization of the entangled two-photon component constitutes a diagnostic tool for quantum optics devices.

KW - quant-ph

UR - http://www.scopus.com/inward/record.url?scp=85115292730&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.127.123602

DO - 10.1103/PhysRevLett.127.123602

M3 - Article

VL - 127

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 12

M1 - 123602

ER -