Protecting light communication with random objects

Phys.org  July 17, 2023 Researchers in the Netherlands have developed an optical communication system with two scattering layers to hide both the sender and receiver, by measuring the correlation of the intermediate speckle generated between the two layers. The binary message is modulated as spatially shaped wavefronts, and the high number of transmission modes of the scattering layers allowed for many uncorrelated incident wavefronts to send the same message, making it difficult for an attacker to intercept or decode the message and thus increasing secrecy. They collected 50,000 intermediate speckle patterns and analyzed their correlation distribution using the Kolmogorov-Smirnov (K-S) […]

A display that completely blocks off counterfeits

EurekAlert  January 22, 2021 Researchers in South Korea have developed a device using nanostructures that is capable of encrypting full-color images depending on the polarization of light. The on and off states can be adjusted according to the polarization of the incident light. It displays full-color images during the on state and shows no images in the off state and it can switch between different images. According to the researchers this feature can be utilized as an anti-forgery device security label that appears to be a simple color image to the naked eye but reveals the serial number when a […]