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Q: Fachverband Quantenoptik und Photonik
Q 21: Quantum Technologies: Color Centers II (joint session Q/QI)
Q 21.3: Vortrag
Dienstag, 7. März 2023, 11:30–11:45, F442
Overcoming spectral diffusion of NV defect centers in diamond nanostructures for enhanced entanglement generation — •Laura Orphal-Kobin1, Kilian Unterguggenberger1, Tommaso Pregnolato1,2, Natalia Kemf2, Mathias Matalla2, Ralph-Stephan Unger2, Ina Ostermay2, Gregor Pieplow1, and Tim Schröder1,2 — 1Department of Physics, Humboldt-Universität zu Berlin, Berlin, Germany — 2Ferdinand-Braun-Institut gGmbH, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany
In large-distance quantum networks, quantum nodes are entangled by single photons. Using NV defect centers in diamond, network entanglement protocols were demonstrated in bulk-like microstructured samples. Performances could be significantly improved by coupling NVs to nanostructures, which increases the photon collection efficiency into a particular optical mode. However, ionization of surface defects leads to spectral diffusion of the NV zero-phonon-line resonance.
We demonstrate NVs in nanostructures that exhibit spectrally stable emission suited for entanglement generation [1]. Choosing a substrate with a high density of bulk nitrogen defects incorporates natural NVs and seems to screen fluctuating electric fields from the surface. Moreover, long ionization times allow for resonant control sequences in which high energy pulses can be circumvented for many entanglement attempt repetitions (optical π-pulses). By suppressing spectral diffusion, we propose spin-photon entanglement rates on the order of hundreds of kHz using NVs in nanostructures.
[1] L. Orphal-Kobin et al., arXiv:2203.05605 (2022).