3,923 research outputs found
Sensitivity Optimization for NV-Diamond Magnetometry
Solid-state spin systems including nitrogen-vacancy (NV) centers in diamond
constitute an increasingly favored quantum sensing platform. However, present
NV ensemble devices exhibit sensitivities orders of magnitude away from
theoretical limits. The sensitivity shortfall both handicaps existing
implementations and curtails the envisioned application space. This review
analyzes present and proposed approaches to enhance the sensitivity of
broadband ensemble-NV-diamond magnetometers. Improvements to the spin dephasing
time, the readout fidelity, and the host diamond material properties are
identified as the most promising avenues and are investigated extensively. Our
analysis of sensitivity optimization establishes a foundation to stimulate
development of new techniques for enhancing solid-state sensor performance.Comment: 73 pages, 36 figures, 17 table
Ultralong Dephasing Times in Solid-State Spin Ensembles via Quantum Control
Quantum spin dephasing is caused by inhomogeneous coupling to the
environment, with resulting limits to the measurement time and precision of
spin-based sensors. The effects of spin dephasing can be especially pernicious
for dense ensembles of electronic spins in the solid-state, such as for
nitrogen-vacancy (NV) color centers in diamond. We report the use of two
complementary techniques, spin bath control and double quantum coherence, to
enhance the inhomogeneous spin dephasing time () for NV ensembles by
more than an order of magnitude. In combination, these quantum control
techniques (i) eliminate the effects of the dominant NV spin ensemble dephasing
mechanisms, including crystal strain gradients and dipolar interactions with
paramagnetic bath spins, and (ii) increase the effective NV gyromagnetic ratio
by a factor of two. Applied independently, spin bath control and double quantum
coherence elucidate the sources of spin dephasing over a wide range of NV and
spin bath concentrations. These results demonstrate the longest reported
in a solid-state electronic spin ensemble at room temperature, and
outline a path towards NV-diamond magnetometers with broadband femtotesla
sensitivity.Comment: PRX versio
Quantum Diamond Microscope for Dynamic Imaging of Magnetic Fields
Wide-field imaging of magnetic signals using ensembles of nitrogen-vacancy
(NV) centers in diamond has garnered increasing interest due to its combination
of micron-scale resolution, millimeter-scale field of view, and compatibility
with diverse samples from across the physical and life sciences. Recently,
wide-field NV magnetic imaging based on the Ramsey protocol has achieved
uniform and enhanced sensitivity compared to conventional measurements. Here,
we integrate the Ramsey-based protocol with spin-bath driving to extend the NV
spin dephasing time and improve magnetic sensitivity. We also employ a
high-speed camera to enable dynamic wide-field magnetic imaging. We benchmark
the utility of this quantum diamond microscope (QDM) by imaging magnetic fields
produced from a fabricated wire phantom. Over a field of view, a median per-pixel
magnetic sensitivity of
is realized with a
spatial resolution
and
sub-millisecond temporal resolution. Importantly, the spatial magnetic noise
floor can be reduced to the picotesla scale by time-averaging and signal
modulation, which enables imaging of a magnetic-field pattern with a
peak-to-peak amplitude difference of about .
Finally, we discuss potential new applications of this dynamic QDM in studying
biomineralization and electrically-active cells.Comment: 18 Pages, 13 figure
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