Ultrasensitive Magnetometer using a Single Atom

I. Baumgart, J. M. Cai, A. Retzker, M. B. Plenio, Ch Wunderlich*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


Precision sensing, and in particular high precision magnetometry, is a central goal of research into quantum technologies. For magnetometers, often trade-offs exist between sensitivity, spatial resolution, and frequency range. The precision, and thus the sensitivity of magnetometry, scales as 1/T2 with the phase coherence time T2 of the sensing system playing the role of a key determinant. Adapting a dynamical decoupling scheme that allows for extending T2 by orders of magnitude and merging it with a magnetic sensing protocol, we achieve a measurement sensitivity even for high frequency fields close to the standard quantum limit. Using a single atomic ion as a sensor, we experimentally attain a sensitivity of 4.6 pT/Hz for an alternating-current magnetic field near 14 MHz. Based on the principle demonstrated here, this unprecedented sensitivity combined with spatial resolution in the nanometer range and tunability from direct current to the gigahertz range could be used for magnetic imaging in as of yet inaccessible parameter regimes.

Original languageAmerican English
Article number240801
JournalPhysical Review Letters
Issue number24
StatePublished - 17 Jun 2016

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Publisher Copyright:
© 2016 American Physical Society.


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