Enhancing the Spin-Coherence Times for Nanodiamonds with Near-Surface NV-centres for Free Radical Detection

Malalasena, VIrun (2025) Enhancing the Spin-Coherence Times for Nanodiamonds with Near-Surface NV-centres for Free Radical Detection. Research Paper, Nanoscience.

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Abstract

In the medical field, magnetic resonance imaging systems generally lack the sensitivity to detect weak signals associated with free radicals, such as those arising from their magnetic moments. This is important as conditions such as sepsis are associated with the presence of free radicals in patients. Quantum sensors are promising devices that offer better resolution and sensitivity compared to their classical counterparts, as they take advantage of effects such as spin dynamics. Nitrogen-vacancy centres (NV-centres), a type of quantum sensor, are situated near the nanodiamond surface and can detect free radicals through T1 relaxometry. Beyond their relaxation times, the spin-coherence time of the NV-centres can serve as an additional parameter that enables more precise studies of free radicals. However, surface characteristics, namely paramagnetic defects and dangling bonds, significantly reduce the coherence time of the NV-centre. This review paper explores various synthesis techniques and surface treatments to improve the surface characteristics of the nanodiamonds. Additionally, the coherence time of the NV centre is determined through microwave pulsed optically detected magnetic resonance experiments and can be extended using specific pulse sequences. This paper will also examine the coherence times achieved with various microwave pulse sequences.

Item Type:	Thesis (Research Paper)
Supervisor name:	Wal, C.H. van der
Degree programme:	Nanoscience
Thesis type:	Research Paper
Language:	English
Date Deposited:	03 Jun 2025 09:05
Last Modified:	03 Jun 2025 09:05
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/35287

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