Spontaneous Parametric Down-Conversion from Resonant Metasurfaces

TL;DR

This paper demonstrates the first generation of photon pairs via spontaneous parametric-down conversion in lithium niobate quantum optical metasurfaces, enabling enhanced and tunable entangled photon sources for quantum optics.

Contribution

It introduces the novel use of resonant all-dielectric metasurfaces for efficient photon-pair generation through SPDC, with controlled spectral properties.

Findings

Photon-pair generation rate enhanced up to 100 times near resonance

Spectral tailoring of photon pairs achieved via metasurface engineering

Potential for flat-optics entangled photon sources in quantum experiments

Abstract

All-dielectric optical metasurfaces are a workhorse in nano-optics due to both their ability to manipulate light in different degrees of freedom and their excellent performance at light frequency conversion. Here, we demonstrate first-time generation of photon pairs via spontaneous parametric-down conversion in lithium niobate quantum optical metasurfaces with electric and magnetic Mie-like resonances at various wavelengths. By engineering the quantum optical metasurface, we tailor the photon-pair spectrum in a controlled way. Within a narrow bandwidth around the resonance, the rate of pair production is enhanced up to two orders of magnitude compared to an unpatterned film of the same thickness and material. These results enable flat-optics sources of entangled photons -- a new promising platform for quantum optics experiments.