A new metasurface, which is extremely thin, aims to replace complex and bulky quantum setups, offering scalability and stability by controlling quantum entanglement.
Harvard researchers have developed a breakthrough metasurface that could significantly reduce the size and complexity of quantum optical systems. The newly designed ultra-thin chip replaces bulky components such as mirrors, beam splitters, and waveguides, commonly used in traditional quantum optics setups.
This innovation addresses one of the key challenges in quantum technologies, scalability. Quantum computers and communication systems rely heavily on entangled photons, which typically require intricate assemblies of optical hardware to manipulate light with high precision. These conventional systems are difficult to maintain, sensitive to disturbance, and challenging to scale for larger applications.
The Harvard team, based at the John A. Paulson School of Engineering and Applied Sciences, created a metasurface with nanoscale structures capable of generating and controlling entangled photon states. Unlike conventional microchips that still depend on embedded optical elements, the flat surface design delivers full optical functionality with fewer components and reduced loss.
What sets this approach apart is its integration of graph theory. The researchers used mathematical models to represent photon interactions and interference patterns, allowing them to design metasurfaces that mimic complex quantum behaviours. This method enables accurate control over photon properties like phase and polarisation, while avoiding the exponential growth in hardware typically needed for multi-photon systems.
The results offer a new direction for scalable, room-temperature quantum systems and suggest broader applications in sensing, communication, and lab-on-chip quantum experiments. The work was supported by the US Air Force Office of Scientific Research and published in Science.
By merging nanophotonics with graph-based quantum logic, the research signals a potential shift from conventional bulk optics to programmable, flat platforms that could transform how quantum technologies are built and deployed.
