Quantum metasurface for multi-photon interference and state reconstruction

TL;DR

This paper demonstrates that all-dielectric metasurfaces can enable multi-photon quantum interference and state reconstruction at the subwavelength scale, advancing quantum photonics with ultra-thin, scalable devices for quantum imaging and communication.

Contribution

It introduces a novel metasurface platform capable of imaging and reconstructing multi-photon quantum states, including entanglement, with potential scalability to higher photon numbers.

Findings

Achieved multi-photon interference at subwavelength scale.

Enabled quantum state reconstruction using a single metasurface.

Theoretically scalable to higher photon numbers.

Abstract

Metasurfaces based on resonant nanophotonic structures have enabled novel types of flat-optics devices often outperforming the capabilities of bulk components, yet these advances remain largely unexplored for quantum applications. We show that non-classical multi-photon interferences can be achieved at the subwavelength scale in all-dielectric metasurfaces. We simultaneously image multiple projections of quantum states with a single metasurface, enabling a robust reconstruction of amplitude, phase, coherence, and entanglement of multi-photon polarization-encoded states. One- and two-photon states are reconstructed through nonlocal photon correlation measurements with polarization-insensitive click-detectors positioned after the metasurface, and the scalability to higher photon numbers is established theoretically. Our work illustrates the feasibility of ultra-thin quantum metadevices for the manipulation and measurement of multi-photon quantum states with applications in free-space quantum imaging and communications.