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A single molecule as a high-fidelity photon gun for producing intensity-squeezed light


A two-level atom cannot emit more than one photon at a time. As early as the 1980s, this quantum feature was identified as a gateway to ‘single-photon sources’, where a regular excitation sequence would create a stream of light particles with photon number fluctuations below the shot noise1. Such an intensity-squeezed beam of light would be desirable for a range of applications, such as quantum imaging, sensing, enhanced precision measurements and information processing2,3. However, experimental realizations of these sources have been hindered by large losses caused by low photon-collection efficiencies and photophysical shortcomings. By using a planar metallodielectric antenna applied to an organic molecule, we demonstrate the most regular stream of single photons reported to date. The measured intensity fluctuations were limited by our detection efficiency and amounted to 2.2 dB squeezing.

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Figure 1: Antenna design for a 99% collection efficiency from a single molecule.
Figure 2: Characterization of single-molecule SPS.
Figure 3: A regular stream of single photons leads to intensity-squeezed light.


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We thank X.-W. Chen for help with the antenna design and simulation. This project was supported by the European Union (European Research Council Advanced Grant SINGLEION) and the SIQUTE (single photon sources for quantum technologies) project of the European Metrology Research Program, an Alexander von Humboldt professorship and the Max Planck Society.

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S.G. and V.S. conceived and supervised the project. X.-L.C. performed the experiments and analysed the data. All the authors prepared the manuscript.

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Correspondence to Stephan Götzinger or Vahid Sandoghdar.

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The authors declare no competing financial interests.

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Chu, XL., Götzinger, S. & Sandoghdar, V. A single molecule as a high-fidelity photon gun for producing intensity-squeezed light. Nature Photon 11, 58–62 (2017).

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