Biphoton transmission through non-unitary objects

Matthew Reichert, Hugo Defienne, Xiaohang Sun, Jason W. Fleischer

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Losses should be accounted for in a complete description of quantum imaging systems, and yet they are often treated as undesirable and largely neglected. In conventional quantum imaging, images are built up by coincidence detection of spatially entangled photon pairs (biphotons) transmitted through an object. However, as real objects are non-unitary (absorptive), part of the transmitted state contains only a single photon, which is overlooked in traditional coincidence measurements. The single-photon part has a drastically different spatial distribution than the two-photon part. It contains information about both the object, and, remarkably, the spatial entanglement properties of the incident biphotons. Here, we image the one- and two-photon parts of the transmitted state using an electron multiplying CCD array, treating it both as a traditional camera and as a massively parallel coincidence counting apparatus, and demonstrate agreement with theoretical predictions of non-unitary quantum optics. This work may prove useful for photon-number imaging and may lead to techniques for entanglement characterization that do not require coincidence measurements.

Original languageEnglish (US)
Article number044004
JournalJournal of Optics (United Kingdom)
Issue number4
StatePublished - Apr 2017

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


  • photon statistics
  • quantum detectors
  • quantum imaging
  • quantum optics
  • spatial entanglement


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