Single photons produced by fundamentally dissimilar physical processes will in general not be indistinguishable. We show how photons produced from a quantum dot and by parametric down-conversion in a nonlinear crystal can be manipulated to be indistinguishable. The measured two-photon coalescence probability is 16%, and is limited by quantum-dot decoherence. Temporal filtering to the quantum dot coherence time and accounting for detector time response increases this to 61% while retaining 25% of the events. This technique can connect different elements in a scalable quantum network.
@article{arxiv.1109.6254,
title = {Coalescence of Single Photons Emitted by Disparate Single Photon Sources: The Example of InAs Quantum Dots and Parametric Down-Conversion Sources},
author = {Sergey V. Polyakov and Andreas Muller and Edward B. Flagg and Alex Ling and Natalia Borjemscaia and Edward Van Keuren and Alan Migdall and Glenn S. Solomon},
journal= {arXiv preprint arXiv:1109.6254},
year = {2015}
}