Hannover 2013 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 35: Poster I

Q 35.79: Poster

Dienstag, 19. März 2013, 16:00–18:30, Empore Lichthof

Magnetic sensing using nitrogen-vacancy centres in diamond nanocrystals — •Helena Knowles, Dhiren Kara, and Mete Atature — University of Cambridge, United Kingdom

Nitrogen-vacancy (NV) centres in diamond are point defects in the diamond lattice that form an electronic spin state S = 1 with sublevels m_s =0 and ± 1 that are Zeeman shifted in a magnetic field. This spin can be initialised and read out optically, and driven coherently with a microwave field. Ramsey type interferometry then enables the detection of magnetic fields at the site of the NV defect.

Compared to NV centres in ultra-pure bulk diamond, nanodiamonds have a higher concentration of spins surrounding the defect reducing the coherence time of the NV spin and its sensitivity as a magnetometer. However, due to their small spatial extent and the possibility of precise positioning of the crystal on the nanometre scale, NV centres in nanocrystals provide the ideal system for high precision spatially resolved magnetometry. We demonstrate the ability to move 15 nm diameter nanocrystals containing single NV defects using an atomic force microscope. We then perform multi-pulse decoupling sequences and extract magnetic field sensitivities of 0.5 µT /√Hz in the shot noise limit.