We demonstrate the tunable quantum beat of single photons through the co-development of core nonlinear nanophotonic technologies for frequency-domain manipulation of quantum states in a common physical platform. Spontaneous four-wave mixing in a nonlinear resonator is used to produce non-degenerate, quantum-correlated photon pairs. One photon from each pair is then frequency shifted, without degradation of photon statistics, using four-wave mixing Bragg scattering in a second nonlinear resonator. Fine tuning of the applied frequency shift enables tunable quantum interference of the two photons as they are impinged on a beamsplitter, with an oscillating signature that depends on their frequency difference. Our work showcases the potential of nonlinear nanophotonic devices as a valuable resource for photonic quantum information science.
@article{arxiv.1905.01698,
title = {Tunable quantum beat of single photons enabled by nonlinear nanophotonics},
author = {Qing Li and Anshuman Singh and Xiyuan Lu and John Lawall and Varun Verma and Richard Mirin and Sae Woo Nam and Kartik Srinivasan},
journal= {arXiv preprint arXiv:1905.01698},
year = {2019}
}