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.
@article{arxiv.2108.04503,
title = {Quantum sum-frequency interference using up-converted photon pairs},
author = {A. Syouji and R. Shimizu and S. Nagano and K. Suizu and K. Edamatsu},
journal= {arXiv preprint arXiv:2108.04503},
year = {2021}
}