We investigate the photo-induced spin dynamics of single nitrogen-vacancy (NV) centres in diamond near the electronic ground state level anti-crossing (GSLAC), which occurs at an axial magnetic field ...around 1024 G. Using optically detected magnetic resonance spectroscopy, we first find that the electron spin transition frequency can be tuned down to 100 kHz for the \NV{14} centre, while for the \NV{15} centre the transition strength vanishes for frequencies below about 2 MHz owing to the GSLAC level structure. Using optical pulses to prepare and readout the spin state, we observe coherent spin oscillations at 1024 G for the \NV{14}, which originate from spin mixing induced by residual transverse magnetic fields. This effect is responsible for limiting the smallest observable transition frequency, which can span two orders of magnitude from 100 kHz to tens of MHz depending on the local magnetic noise. A similar feature is observed for the \NV{15} centre at 1024 G. As an application of these findings, we demonstrate all-optical detection and spectroscopy of externally-generated fluctuating magnetic fields at frequencies from 8 MHz down to 500 kHz, using a \NV{14} centre. Since the Larmor frequency of most nuclear spin species lies within this frequency range near the GSLAC, these results pave the way towards all-optical, nanoscale nuclear magnetic resonance spectroscopy, using longitudinal spin cross-relaxation.
We demonstrate quantum interference between indistinguishable photons emitted by two nitrogen-vacancy (NV) centers in distinct diamond samples separated by two meters. Macroscopic solid immersion ...lenses are used to enhance photon collection efficiency. Quantum interference is verified by measuring a value of the second-order cross-correlation function \(g^{(2)}(0) = 0.35 \pm 0.04<0.5\). In addition, optical transition frequencies of two separated NV centers are tuned into resonance with each other by applying external electric fields. Extension of the present approach to generate entanglement of remote solid-state qubits is discussed.
PAPERS IN AGRICULTURE POUND, MATTHEW; Thoroton, John; Wood, William ...
Transactions of the Society, Instituted at London, for the Encouragement of Arts, Manufactures, and Commerce,
01/1816, Letnik:
34
Journal Article
