Entangled photon pairs have been promised to deliver a substantial quantum advantage for two-photon absorption spectroscopy. However, recent work has challenged the previously reported magnitude of quantum enhancement in two-photon absorption. Here, we present an experimental comparison of sum-frequency generation and molecular absorption, each driven by isolated photon pairs. We establish an upper bound on the enhancement for entangled-two-photon absorption in Rhodamine-6G, which lies well below previously reported values.
@article{arxiv.2012.06736,
title = {Experimental feasibility of molecular two-photon absorption with isolated time-frequency-entangled photon pairs},
author = {Tiemo Landes and Markus Allgaier and Sofiane Merkouche and Brian J. Smith and Andrew H. Marcus and Michael G. Raymer},
journal= {arXiv preprint arXiv:2012.06736},
year = {2021}
}