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Atomic, Mesoscopic and Optical Physics

AMOP Group

The Quantum Nano-Sensors Lab ( is a recently established group at the Cavendish Laboratory. We are interested in imaging matter at the few-particle, few-spin level and probing structure, dynamics and interactions at the nanometre scale in a non-invasive way.

We use quantum optics tools and coherent control techniques to manipulate the quantum state of defect spins in solids. These defects can act as single-atom-sized quantum sensors and allow us to address important questions about interactions on the single-molecule scale, reveal the underlying physics of new designer materials and explore hidden quantum mechanical phenomena at the nanometre scale.

In particular, we focus on the following research topics:

Nanoscale spin imaging and sensing:

We use atomic defects in diamond, so-called nitrogen-vacancy (NV) centres, to probe nearby spins at the nanometre scale. This technique provides non-invasive sensing with unprecedented spatial resolution and allows us to perform nuclear magnetic resonance (NMR) studies of only a few 1000 nuclear spins. We aim to push the sensitivity and spectral resolution of these sensors to perform chemically resolved NMR in nanoscale volumes.

Knowles et al., Nat. Mater. 13, 21–25 (2014)
Knowles et al., PRL 117, 100802 (2016) 
Holzgrafe et al., Phys. Rev. Appl. 13 044004 (2019)

Hamiltonian engineering of spin ensembles:

A newly-developed, versatile toolkit for spin control allows the engineering of spin-spin interactions and local disorder in an ensemble of spins, using only global control pulses. We will explore the possibilities this toolkit provides for Hamiltonian engineering in dense spin ensembles in 2D and 3D systems.

Choi et al., Phys. Rev. X 10 031002 (2020)
H. Zhou et al Phys. Rev. X 10 031003 (2020)

Enhanced readout techniques:

We are working on enhanced readout techniques, incorporating nuclear spin memories and error correction protocols, to boost the signal-to-noise ratio of NV sensors.

Knowles et al., Phys. Rev. B. 96 115206 (2017)
Holzgrafe et al., npj Quantum Inf. 5 13 (2019)

New materials discovery using quantum sensors:

Scanning probe quantum sensing using NV centres allows the mapping of magnetic and conductance features on the nanoscale under a wide range of temperatures and external magnetic field strengths. We are working on applying this technique to layered magnetic structures with topologically protected spin textures.


Temperature sensing in single-cell organisms:

Funded by a grant from the Moore Foundation, this interdisciplinary project is addressing questions at the nanoscale in living organisms. We use NV centres in diamond nanocrystals, which act as bio-compatible nano-sensors, to probe magnetic field and temperature at the nanoscale in single-cell organisms.

Opportunities: Interested in joining the group? Get in touch! 
(Please send CV to H. S. Knowles at hsk35 (a)

We are currently accepting applications for PhD positions and a postdoc position: