Experimental feasibility of molecular two-photon absorption with isolated time-frequency-entangled photon pairs

TL;DR

This paper experimentally compares sum-frequency generation and molecular absorption driven by entangled photon pairs, establishing a lower-than-expected quantum enhancement in two-photon absorption for Rhodamine-6G, challenging prior claims.

Contribution

It provides the first direct experimental comparison of sum-frequency generation and molecular absorption with entangled photons, setting new bounds on quantum enhancement in two-photon absorption.

Findings

Quantum enhancement in two-photon absorption is lower than previously reported.

Upper bound on entangled-two-photon absorption enhancement in Rhodamine-6G.

Experimental comparison clarifies limitations of entangled photon applications.

Abstract

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.