29 research outputs found
Biocompatible technique for nanoscale magnetic field sensing with Nitrogen-Vacancy centers
The possibility of using Nitrogen-vacancy centers in diamonds to measure
nanoscale magnetic fields with unprecedented sensitivity is one of the most
significant achievements of quantum sensing. Here we present an innovative
experimental set-up, showing an achieved sensitivity comparable to the state of
the art ODMR protocols if the sensing volume is taken into account. The
apparatus allows magnetic sensing in biological samples such as individual
cells, as it is characterized by a small sensing volume and full
bio-compatibility. The sensitivity at different optical powers is studied to
extend this technique to the intercellular scale.Comment: 6 pages, 5 figure
Creation and characterization of He-related color centers in diamond
Diamond is a promising material for the development of emerging applications
in quantum optics, quantum information and quantum sensing. The fabrication and
characterization of novel luminescent defects with suitable opto-physical
properties is therefore of primary importance for further advances in these
research fields. In this work we report on the investigation in the formation
of photoluminescent (PL) defects upon MeV He implantation in diamond. Such
color centers, previously reported only in electroluminescence and
cathodoluminescence regime, exhibited two sharp emission lines at 536.5 nm and
560.5 nm, without significant phonon sidebands. A strong correlation between
the PL intensities of the above-mentioned emission lines and the He
implantation fluence was found in the 10^15-10^17 cm^{-2} fluence range. The PL
emission features were not detected in control samples, i.e. samples that were
either unirradiated or irradiated with different ion species (H, C). Moreover,
the PL emission lines disappeared in samples that were He-implanted above the
graphitization threshold. Therefore, the PL features are attributed to
optically active defects in the diamond matrix associated with He impurities.
The intensity of the 536.5 nm and 560.5 nm emission lines was investigated as a
function of the annealing temperature of the diamond substrate. The emission
was observed upon annealing at temperatures higher than 500{\deg}C, at the
expenses of the concurrently decreasing neutral-vacancy-related GR1 emission
intensity. Therefore, our findings indicate that the luminescence originates
from the formation of a stable lattice defect. Finally, the emission was
investigated under different laser excitations wavelengths (i.e. 532 nm and 405
nm) with the purpose of gaining a preliminary insight about the position of the
related levels in the energy gap of diamond
Spectral features of Pb-related color centers in diamond – a systematic photoluminescence characterization
We report on the systematic characterization of the optical properties of
diamond color centers based on Pb impurities. An ensemble photoluminescence
analysis of their spectral emission was performed at different excitation
wavelengths in the 405-520 nm range and at different temperatures in the 4-300
K range. The series of observed spectral features consist of different emission
lines associated with Pb-related defects. Finally, a room-temperature
investigation of single-photon emitters under 490.5 nm laser excitation is
reported, revealing different spectral signatures with respect to those already
reported under 514 nm excitation. This work represents a substantial progress
with respect to previous studies on Pb-related color centers, both in the
attribution of an articulated series of spectral features and in the
understanding of the formation process of this type of defect, thus clarifying
the potential of this system for high-impact applications in quantum
technologies