# An on-chip phased array for non-classical light

## TL;DR

Researchers developed a chip-based phased array system to manipulate non-classical light, advancing wireless quantum technologies.

## Contribution

The novel system integrates a large-scale quantum-limited receiver array for free-space non-classical light manipulation on a chip.

## Key findings

- Demonstrated a 32-pixel imaging system using squeezed light over free space.
- Achieved spatially configurable reception and beamsteering of non-classical signals.
- Integrated over 1000 components on a chip for coherent readout of quantum signals.

## Abstract

Quantum science and technology can offer fundamental enhancements in sensing, communications and computing. The expansion from wired to wireless links is an exciting prospect for quantum technologies. For classical technologies, the advent of phased arrays enabled directional and adaptive wireless links by manipulating electromagnetic waves over free space. Here we demonstrate a phased array system on a chip that can receive, image and manipulate non-classical light over free space. We use an integrated photonic-electronic system with more than 1000 functional components on-chip to detect squeezed light. By integrating an array of 32 sub-wavelength engineered metamaterial antennas, we demonstrate a direct free-space-to-chip interface for reconfigurable quantum links. On the same chip, we implement a large-scale array of quantum-limited coherent receivers that can resolve non-classical signals simultaneously across 32 channels. With coherent readout and manipulation of these signals, we demonstrate 32-pixel imaging and spatially configurable reception of squeezed light over free space. Our work advances wireless quantum technologies that could enable practical applications in quantum communications and sensing.

Extending the use of phased arrays (i.e. coherent arrays of antenna elements) to non-classical states of light would be useful for several quantum technologies, but losses and transceivers noise have hindered efforts so far. Here, the authors demonstrate a silicon photonic-electronic system able to perform 32-pixel imaging, beamforming and beamsteering of squeezed light transmitted over free space toward unlocking wireless applications of quantum technologies.