Quantum holograms can send messages that disappear

A groundbreaking study has revealed a new way to embed secure messages in holograms and erase specific parts of them even after transmission. Quantum technology has unlocked the potential for secure information transfer through quantum light signals, where any attempt to intercept the message destroys the delicate quantum states that encode it. Researchers, led by Jensen Li from the University of Exeter in the UK, have harnessed the power of metasurfaces to create quantum holograms.

Holograms are intricate forms of visual data that can be decoded when illuminated – similar to how a 2D holographic card displays 3D images under specific lighting conditions. In this study, the researchers encoded information into the quantum state of a photon to create a quantum hologram. By utilizing a laser to generate two entangled photons from a special crystal, the team manipulated one of the photons using a metasurface along its path. The metasurface, composed of nano-sized components, altered the photon’s quantum state to encode a holographic image.

One of the key innovations in this study was the use of a polarised filter on the partner photon, which determined which parts of the hologram would be visible and which would vanish. Since the first photon’s state encompassed multiple holographic variations simultaneously, the application of a polarised filter on the second photon impacted the final image that would be captured by a camera. For instance, by introducing a filter for horizontally polarised light, the researchers were able to erase specific elements, such as the letter ‘H,’ from the holographic message.

Li envisions that the metasurface technology could be further developed to encode more intricate information into photons, potentially enhancing quantum cryptography protocols. The study was presented at the SPIE Optics + Photonics conference in San Diego, California, showcasing the promising applications of quantum holograms in various fields, including quantum communication and medical imaging.

Andrew Forbes from the University of the Witwatersrand in South Africa praised the study’s findings, highlighting the potential for compact quantum technology that could revolutionize information security and imaging technologies. Quantum holograms offer a glimpse into the future of secure communication and high-resolution imaging, paving the way for advancements in diverse industries.