Polarized light can make messages encoded in quantum holograms disappear.
Hong Liang, Wai Chun Wong, Tailin An, Jensen Li 2024
Quantum annihilation technology allows us to embed secure messages into holograms and selectively erase parts of them after the message has been sent.
Quantum optical signals are inherently secure information carriers, because intercepting the message destroys the fragile quantum state that encodes it. To utilize this without using bulky devices, jensen lee The University of Exeter in the UK and his colleagues MetasurfaceA 2D material designed with special properties to create quantum holograms.
Holograms encode complex information that can be recovered by illuminating it. For example, a 2D holographic paper card shows a 3D image when light is shone at the right angle. To create quantum holograms, researchers have encoded information into the quantum states of light particles, or photons.
First, they used a laser to cause a special crystal to emit two photons that were inextricably linked by quantum entanglement. The photons traveled separate paths, with only one photon encountering the metasurface along the way. Thousands of tiny components on the metasurface, such as nanoscale bumps, altered the photons’ quantum state in a preprogrammed way, encoding a holographic image.
The partner photon encountered a polarizing filter, which controlled which parts of the hologram were revealed and which were lost. The state of the first photon was a superposition of holograms, so it contained multiple possible variations of the message simultaneously. Because the photons were entangled, polarizing the second photon affected the image created by the other photon when it hit the camera. For example, the test hologram contained the letters H, D, V, and A, but adding a filter for horizontally polarized light erased the letter H from the final image.
Li says metasurfaces could be used to encode more complex information into photons, for example as part of quantum cryptography protocols. He says the work SPIE Optics + Photonics Conference August 21st in San Diego, California.
“Everyone’s dream is to see all this quantum technology spread out over several square meters on a table compact enough to fit on a smartphone. Metasurfaces seem like a good way to do that. [about that]he says Andrew Forbes At the University of the Witwatersrand in South Africa, quantum holography, like that in the new experiment, could also be used to image tiny biological structures in medicine, a rapidly expanding field, he says.
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