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arXiv · 1702.06710

Quantum Sensing of Weak Radio-Frequency Signals by Pulsed Mollow Absorption Spectroscopy

Timo Joas·Andreas M. Waeber·Georg Braunbeck·Friedemann Reinhard
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Abstract

Quantum sensors, qubits sensitive to external fields, have become powerful detectors for various small acoustic and electromagnetic fields. A major key to their success have been dynamical decoupling protocols which enhance sensitivity to weak oscillating (AC) signals. Currently, those methods are limited to signal frequencies below a few MHz. Here we harness a quantum-optical effect, the Mollow triplet splitting of a strongly driven two-level system, to overcome this limitation. We microscopically understand this effect as a pulsed dynamical decoupling protocol and find that it enables sensitive detection of fields close to the driven transition. Employing a nitrogen-vacancy center, we detect GHz microwave fields with a signal strength (Rabi frequency) below the current detection limit, which is set by the center's spectral linewidth 1/T2*. Pushing detection sensitivity to the much lower 1/T2 limit, this scheme could enable various applications, most prominently coherent coupling to single phonons and microwave photons.

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Timo Joas, Andreas M. Waeber, Georg Braunbeck, Friedemann Reinhard. 2017-02-22. Quantum Sensing of Weak Radio-Frequency Signals by Pulsed Mollow Absorption Spectroscopy. https://doi.org/10.1038/s41467-017-01158-3

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