Transmission of hidden images within noise

Steven Johnson, Alex McMillan*, Stefan Frick*, John Rarity*, Miles Padgett

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


The secure transmission of an image can be accomplished by encoding the image information, securely communicating this information, and subsequently reconstructing the image. As an alternative, here we show how the image itself can be directly transmitted while ensuring that the presence of any cavesdropper is revealed in a way akin to quantum key distribution. We achieve this transmission using a photon-pair source with the deliberate addition of a thermal light source as background noise. One photon of the pair illuminates the object, which is masked from an eavesdropper by adding indistinguishable thermal photons, the other photon of the pair acts as a time reference from which the intended recipient can preferentially detect the image carrying photons. These reference photons are themselves made sensitive to the presence of an eavesdropper by traditional polarisation-based QKD encoding. Interestingly the security encoding is performed in the two-dimensional polarisation-basis, but the image information is encoded in a much higher-dimensional, hence information-rich, pixel basis. In our example implementation, our images have more than 100 independent pixels. Beyond the secure transmission of images, our approach to the distribution of secure high-dimensional information may create new high-bandwidth approaches to traditional QKD.

Original languageEnglish
Article number129120U
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 13 Mar 2024
EventQuantum Sensing, Imaging, and Precision Metrology II 2024 - San Francisco, United States
Duration: 27 Jan 20241 Feb 2024


  • Noise free imaging
  • Quantum Key Distributions


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