In February 2025, researchers from Peking University, Southern University of Science and Technology, and the University of Science and Technology of China unveiled a new method for generating multiphoton entanglement using a single gradient metasurface. Published in *Advanced Photonics Nexus*, the discovery simplifies quantum information processing, which traditionally relies on complex and inefficient optical setups. Metasurfaces, engineered two-dimensional materials, manipulate light properties like phase and polarization. The team's approach involves directing single photons onto a specially designed metasurface, causing them to quantumly interfere and become entangled. This technique enables the creation of various entangled states and the fusion of entangled photon pairs into larger groups, compacting more quantum information into a smaller space.
Professor Ying Gu likened the approach to a shortcut in a maze, streamlining the creation and manipulation of entangled photons for smaller, chip-sized quantum devices. Potential applications include quantum networks capable of delivering entangled photons to multiple users and the development of laptop-sized quantum computers, facilitating secure quantum communication and advanced quantum algorithms.