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arXiv · 1805.02491

Quantum-limited time-frequency estimation through mode-selective photon measurement

John M. Donohue·Vahid Ansari·Jaroslav Řeháček·Zdeněk Hradil·Bohumil Stoklasa·Martin Paúr·Luis L. Sánchez-Soto·Christine Silberhorn
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Abstract

By projecting onto complex optical mode profiles, it is possible to estimate arbitrarily small separations between objects with quantum-limited precision, free of uncertainty arising from overlapping intensity profiles. Here we extend these techniques to the time-frequency domain using mode-selective sum-frequency generation with shaped ultrafast pulses. We experimentally resolve temporal and spectral separations between incoherent mixtures of single-photon level signals ten times smaller than their optical bandwidths with a ten-fold improvement in precision over the intensity-only Cram\'er-Rao bound.

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John M. Donohue, Vahid Ansari, Jaroslav Řeháček, Zdeněk Hradil, Bohumil Stoklasa, Martin Paúr, Luis L. Sánchez-Soto, Christine Silberhorn. 2018-05-07. Quantum-limited time-frequency estimation through mode-selective photon measurement. https://doi.org/10.1103/physrevlett.121.090501

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