33 research outputs found
Optical polarization of nuclear ensembles in diamond
We report polarization of a dense nuclear-spin ensemble in diamond and its
dependence on magnetic field and temperature. The polarization method is based
on the transfer of electron spin polarization of negatively charged nitrogen
vacancy color centers to the nuclear spins via the excited-state level
anti-crossing of the center. We polarize 90% of the 14N nuclear spins within
the NV centers, and 70% of the proximal 13C nuclear spins with hyperfine
interaction strength of 13-14 MHz. Magnetic-field dependence of the
polarization reveals sharp decrease in polarization at specific field values
corresponding to cross-relaxation with substitutional nitrogen centers, while
temperature dependence of the polarization reveals that high polarization
persists down to 50 K. This work enables polarization of the 13C in bulk
diamond, which is of interest in applications of nuclear magnetic resonance, in
quantum memories of hybrid quantum devices, and in sensing.Comment: 8 pages, 5 figure
Microwave-free magnetometry with nitrogen-vacancy centers in diamond
We use magnetic-field-dependent features in the photoluminescence of
negatively charged nitrogen-vacancy centers to measure magnetic fields without
the use of microwaves. In particular, we present a magnetometer based on the
level anti-crossing in the triplet ground state at 102.4 mT with a demonstrated
noise floor of 6 nT/, limited by the intensity noise of the
laser and the performance of the background-field power supply. The technique
presented here can be useful in applications where the sensor is placed closed
to conductive materials, e.g. magnetic induction tomography or magnetic field
mapping, and in remote-sensing applications since principally no electrical
access is needed.Comment: 5 pages, 4 figure
Sidebands in optically detected magnetic resonance signals of nitrogen vacancy centers in diamond
We study features in the optically detected magnetic resonance (ODMR) signals associated with negatively charged nitrogen-vacancy (NV-) centers coupled to other paramagnetic impurities in diamond. Our results are important for understanding ODMR line sha
Temperature shifts of the resonances of the NV-center in diamond
Significant attention has been recently focused on the realization of high precision nanothermometry using the spin-resonance temperature shift of the negatively charged nitrogen-vacancy (NV-) center in diamond. However, the precise physical origins of the temperature shift is yet to be understood. Here, the shifts of the center's optical and spin resonances are observed and a model is developed that identifies the origin of each shift to be a combination of thermal expansion and electron-phonon interactions. Our results provide insight into the center's vibronic properties and reveal implications for NV- thermometry
Magnetometry with nitrogen-vacancy ensembles in diamond based on infrared absorption in a doubly resonant optical cavity
We propose to use an optical cavity to enhance the sensitivity of
magnetometers relying on the detection of the spin state of high-density
nitrogen-vacancy ensembles in diamond using infrared optical absorption. The
role of the cavity is to obtain a contrast in the absorption-detected magnetic
resonance approaching unity at room temperature. We project an increase in the
photon shot-noise limited sensitivity of two orders of magnitude in comparison
with a single-pass approach. Optical losses can limit the enhancement to one
order of magnitude which could still enable room temperature operation.
Finally, the optical cavity also allows to use smaller pumping power when it is
designed to be resonant at both the pump and the signal wavelength
Diamond magnetic microscopy of malarial hemozoin nanocrystals
Magnetic microscopy of malarial hemozoin nanocrystals was performed using
optically detected magnetic resonance imaging of near-surface diamond
nitrogen-vacancy centers. Hemozoin crystals were extracted from
--infected human blood cells and studied alongside
synthetic hemozoin crystals. The stray magnetic fields produced by individual
crystals were imaged at room temperature as a function of applied field up to
350 mT. More than 100 nanocrystals were analyzed, revealing the distribution of
their magnetic properties. Most crystals () exhibit a linear dependence
of stray field magnitude on applied field, confirming hemozoin's paramagnetic
nature. A volume magnetic susceptibility is inferred
using a magnetostatic model informed by correlated scanning electron microscopy
measurements of crystal dimensions. A small fraction of nanoparticles (4/82 for
-produced and 1/41 for synthetic) exhibit a saturation behavior
consistent with superparamagnetism. Translation of this platform to the study
of living malaria-infected cells may shed new light on hemozoin formation
dynamics and their interaction with antimalarial drugs.Comment: Main text: 8 pages and 5 figures, Supplemental Information: 9 pages
and 8 figure
Infrared absorption band and vibronic structure of the nitrogen-vacancy center in diamond
Negatively charged nitrogen-vacancy (NV-) color centers in diamond have generated much interest for use in quantum technology. Despite the progress made in developing their applications, many questions about the basic properties of NV- centers remain unr