76 research outputs found
Temperature and magnetic field dependent longitudinal spin relaxation in nitrogen-vacancy ensembles in diamond
We present an experimental study of the longitudinal electron-spin relaxation
time (T1) of negatively charged nitrogen-vacancy (NV) ensembles in diamond. T1
was studied as a function of temperature from 5 to 475 K and magnetic field
from 0 to 630 G for several samples with various NV and nitrogen
concentrations. Our studies reveal three processes responsible for T1
relaxation. Above room temperature, a two-phonon Raman process dominates, and
below, we observe an Orbach-type process with an activation energy, 73(4) meV,
which closely matches the local vibrational modes of the NV center. At yet
lower temperatures, sample dependent cross relaxation processes dominate,
resulting in temperature independent values of T1, from ms to minutes. The
value of T1 in this limit depends sensitively on magnetic field and can be
tuned by more than an order of magnitude.Comment: 5 pages, 3 figures, and 3 pages of supplemental material with
additional figure
Gyroscopes based on nitrogen-vacancy centers in diamond
We propose solid-state gyroscopes based on ensembles of negatively charged
nitrogen-vacancy () centers in diamond. In one scheme, rotation of
the nitrogen-vacancy symmetry axis will induce Berry phase shifts in the electronic ground-state coherences proportional to the solid angle
subtended by the symmetry axis. We estimate sensitivity in the range of
in a 1 sensor volume using
a simple Ramsey sequence. Incorporating dynamical decoupling to suppress
dipolar relaxation may yield sensitivity at the level of . With a modified Ramsey scheme, Berry phase shifts in the
hyperfine sublevels would be employed. The projected sensitivity
is in the range of , however the smaller
gyromagnetic ratio reduces sensitivity to magnetic-field noise by several
orders of magnitude. Reaching would represent
an order of magnitude improvement over other compact, solid-state gyroscope
technologies.Comment: 3 figures, 5 page
Cavity-enhanced room-temperature magnetometry using absorption by nitrogen-vacancy centers in diamond
We demonstrate a cavity-enhanced room-temperature magnetic field sensor based
on nitrogen-vacancy centers in diamond. Magnetic resonance is detected using
absorption of light resonant with the 1042 nm spin-singlet transition. The
diamond is placed in an external optical cavity to enhance the absorption, and
significant absorption is observed even at room temperature. We demonstrate a
magnetic field sensitivity of 2.5 nT/sqrt(Hz), and project a photon
shot-noise-limited sensitivity of 70 pT/sqrt(Hz) for a few mW of infrared
light, and a quantum projection-noise-limited sensitivity of 250 fT/sqrt(Hz)
for the sensing volume of 90 um x 90 um 200 um.Comment: main text 5 pages, supplementary material 3 page
Longitudinal spin-relaxation in nitrogen-vacancy centers in electron irradiated diamond
We present systematic measurements of longitudinal relaxation rates ()
of spin polarization in the ground state of the nitrogen-vacancy (NV) color
center in synthetic diamond as a function of NV concentration and magnetic
field . NV centers were created by irradiating a Type 1b single-crystal
diamond along the [100] axis with 200 keV electrons from a transmission
electron microscope with varying doses to achieve spots of different NV
center concentrations. Values of () were measured for each spot as a
function of .Comment: 4 pages, 8 figure
Microwave saturation spectroscopy of nitrogen-vacancy ensembles in diamond
Negatively-charged nitrogen-vacancy (NV) centers in diamond have
generated much recent interest for their use in sensing. The sensitivity
improves when the NV ground-state microwave transitions are narrow, but these
transitions suffer from inhomogeneous broadening, especially in high-density NV
ensembles. To better understand and remove the sources of broadening, we
demonstrate room-temperature spectral "hole burning" of the NV ground-state
transitions. We find that hole burning removes the broadening caused by
magnetic fields from C nuclei and demonstrate that it can be used for
magnetic-field-insensitive thermometry.Comment: Main text: 5 pages, 4 figures. Supplement: 6 pages, 3 figure
Detailed studies of non-linear magneto-optical resonances at D1 excitation of Rb-85 and Rb-87 for partially resolved hyperfine F-levels
Experimental signals of non-linear magneto-optical resonances at D1
excitation of natural rubidium in a vapor cell have been obtained and described
with experimental accuracy by a detailed theoretical model based on the optical
Bloch equations. The D1 transition of rubidium is a challenging system to
analyze theoretically because it contains transitions that are only partially
resolved under Doppler broadening. The theoretical model took into account all
nearby transitions, the coherence properties of the exciting laser radiation,
and the mixing of magnetic sublevels in an external magnetic field and also
included averaging over the Doppler profile. Great care was taken to obtain
accurate experimental signals and avoid systematic errors. The experimental
signals were reproduced very well at each hyperfine transition and over a wide
range of laser power densities, beam diameters, and laser detunings from the
exact transition frequency. The bright resonance expected at the F_g=1 -->
F_e=2 transition of Rb-87 has been observed. A bright resonance was observed at
the F_g=2 --> F_e=3 transition of Rb-85, but displaced from the exact position
of the transition due to the influence of the nearby F_g=2 --> F_e=2
transition, which is a dark resonance whose contrast is almost two orders of
magnitude larger than the contrast of the bright resonance at the F_g=2 -->
F_e=3 transition. Even in this very delicate situation, the theoretical model
described in detail the experimental signals at different laser detunings.Comment: 11 pages, 9 figure
- …