Quantum sum-frequency interference using up-converted photon pairs

TL;DR

This paper presents a hybrid method combining SPDC and up-conversion to generate high-brightness, short-wavelength photon pairs with preserved energy-time correlations, enabling quantum interference with sub-wavelength fringes.

Contribution

It introduces a novel hybrid approach for generating short-wavelength photon pairs with high brightness and preserved quantum correlations, surpassing classical limits.

Findings

Demonstrated quantum sum-frequency interference with 258.3 nm fringe period.

Generated photon pairs at 1550 nm converted to 516.7 nm.

Achieved high brightness and sub-wavelength interference fringes.

Abstract

We demonstrate a hybrid approach to the generation of photon pairs of a short wavelength with high brightness, by combining parametric down-conversion (SPDC) and up-conversion techniques. Photon pairs were generated at the wavelength of 1550 nm via SPDC, and converted to 516.7 nm through up-conversion with the pump at 775 nm. The quantum sum-frequency interference of the up-converted photon pairs exhibited a fringe period of 258.3 nm, which was 6 times shorter than the original wavelength, demonstrating that the energy-time correlation of the photon pairs was preserved. The technique simultaneously provides short fringe period beyond the classical limit and high brightness of the photon pairs.