Metasurfaces as strong linear quantum optical networks, eliminate need for waveguides/ bulky optics, entangle photons on ultra-thin chip

https://www.eurekalert.org/news-releases/1092421

"optics collapsed into single, flat, ultra-thin subwavelength elements array controlling brightness, phase, polarization in exact same way... etched with nanoscale light-manipulating patterns... error-resistant, don’t require intricate alignments, robustness to perturbations, cost-effective, simple fabrication, low optical loss...  adding more qubits no longer requires a rapidly growing number of beam splitters and output ports... metasurfaces, especially for generating and controlling quantum light"