Departmental Seminar

Nanoscale quantum sensing

Dr Liam P. McGuinness
Institute of Quantum Optics, University of Ulm, 89081 Germany

Quantum coherent sensors provide ultra-sensitive, precise and non-invasive detectors beyond what is possible with classical sensors. This talk discusses some of their applications and limitations.

The long-lived quantum coherence of single nitrogen-vacancy (NV) centers in diamond can be used to detect miniscule magnetic fields at room temperature. In addition, their atomic size allows construction of a magnetic detector with nanometer spatial resolution. As a result NV centers have demonstrated magnetic detection of: i) completely unpolarised samples, with ii) single nuclear spin sensitivity, and been applied to iii) room-temperature sample hyperpolarisation.

These results take advantage of the quantum coherent nature of the NV spin, interacting with a quantum coherent sample. As a result, they are limited by the coherence time of the sensor. Recently we have developed techniques allowing one to go beyond the sensor decoherence time in order to improve the sensitivity and spectral resolution of NV magnetometry. The techniques included using quantum error correction and heterodyning to a classical clock.

In this talk, new developments allowing the sensitivity, precision and information scaling of quantum metrology to be enhanced will be discussed.

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