Researchers have discovered a groundbreaking technique to encode images into the quantum correlations of entangled photons, effectively rendering them invisible to standard cameras. This novel approach in quantum imaging has vast potential for secure communication, imaging through scattering media, and beyond.
Hiding in Plain Sight
That is the equivalent of being able to hide an image under the noses of any observer even with not just that type and brand of camera, but with any model ever made or in development. This is what a team of researchers from the Paris Institute of Nanoscience at Sorbonne University managed to do.
Using the quantum properties of entangled photons, researchers have discovered a way to overcome those limitations by selectively encoding visual information on spatial correlations between twin particles of light. In this sense, the image is hidden in the quantum state of the photons and signifies that conventional ways of imaging that are just based on counting individual photons will not be able to observe it.
This process relies on spontaneous parametric down-conversion (SPDC), in which a high-energy photon from an ultraviolet or blue laser is separated into two lower-energy entangled photons. To do this, they encoded an image onto the spatial correlations of the entangled photon pairs by projecting an image onto the nonlinear crystal that the blue laser passes through.
Unveiling the Hidden Image
Although a normal camera would just register an even intensity, unrecognizable without the help of some homemade code provided by the researchers that could decode the image and reveal what it was originally. They have a one-photon sensitive camera, and by looking at coincidences or simultaneous arrivals of entangled photon pairs they can create image based on the spatial correlations in photons.
An artist’s rendering of the technique used in the quantum imaging experiment conducted by CNRS researchers at the Paris Institute of Nanosciences. If you attempt to image it by, in the ordinary way, counting individual photons, you will see nothing. However, “if you measure the simultaneous arrivals of photons and look around the image appears.
This method is versatile and it has the potential to be more applicable due to its relative simplicity in experiment design. But the researchers think that by tuning the crystal and laser properties, it could be possible to encode multiple images into a single entangled photon beam.
Conclusion
The results that are presented in the paper Dubbed hide and seek imagination can be further, beyond our current physical understanding of quantum imaging. If realized, this method could transform secure communication, imaging through scattering media and other applications that leverage the special nature of quantum light. With ongoing research to refine and expand this technology, you can expect to see more virtual reality programs spring up across a number of industries in the future.
