Quantum phased array system on a chip: A prototype for wireless quantum technologies

Wireless quantum technologies that can receive, process and transmit quantum information at room temperature over free space in a standalone, compact form factor are an exciting prospect for expanding the impact of quantum technologies. Here, we introduce the quantum phased array, which extends the operating principles of phased arrays to quantum fields and report its first technology demonstration with an integrated photonic-electronic system. We integrate 32 metamaterial antennas with more than 500,000 sub-wavelength-engineered nanophotonic elements on a silicon photonic chip to demonstrate the first, to our knowledge, free-space-to-chip interface for quantum links. On the same chip, we implement the first, to our knowledge, large-scale array of homodyne detectors that can resolve non-classical signals simultaneously across all 32 channels. With our photonic-electronic system containing more than 1000 functional components, we demonstrate 32-pixel imaging and spatially configurable reception of squeezed light over free space. Our work demonstrates a prototype for a novel class of quantum technologies that can be interfaced wirelessly and shows the potential of wireless quantum technologies toward enabling practical applications of quantum communications and sensing.