14 research outputs found
Creation of NV centers in diamond under 155 MeV electron irradiation
Single-crystal diamond substrates presenting a high concentration of
negatively charged nitrogen-vacancy centers (NV-) are on high demand for the
development of optically pumped solid-state sensors such as magnetometers,
thermometers or electrometers. While nitrogen impurities can be easily
incorporated during crystal growth, the creation of vacancies requires further
treatment. Electron irradiation and annealing is often chosen in this context,
offering advantages with respect to irradiation by heavier particles that
negatively affect the crystal lattice structure and consequently the NV-
optical and spin properties. A thorough investigation of electron irradiation
possibilities is needed to optimize the process and improve the sensitivity of
NV-based sensors. In this work we examine the effect of electron irradiation in
a previously unexplored regime: extremely high energy electrons, at 155 MeV. We
develop a simulation model to estimate the concentration of created vacancies
and experimentally demonstrate an increase of NV- concentration by more than 3
orders of magnitude following irradiation of a nitrogen-rich HPHT diamond over
a very large sample volume, which translates into an important gain in
sensitivity. Moreover, we discuss the impact of electron irradiation in this
peculiar regime on other figures of merits relevant for NV sensing, i.e. charge
state conversion efficiency and spin relaxation time. Finally, the effect of
extremely high energy irradiation is compared with the more conventional low
energy irradiation process, employing 200 keV electrons from a transmission
electron microscope, for different substrates and irradiation fluences,
evidencing sixty-fold higher yield of vacancy creation per electron at 155 MeV
Neuronal growth on high-aspect-ratio diamond nanopillar arrays for biosensing applications
Monitoring neuronal activity with simultaneously high spatial and temporal resolution in living cell cultures is crucial to advance understanding of the development and functioning of our brain, and to gain further insights in the origin of brain disorders. While it has been demonstrated that the quantum sensing capabilities of nitrogen-vacancy (NV) centers in diamond allow real time detection of action potentials from large neurons in marine invertebrates, quantum monitoring of mammalian neurons (presenting much smaller dimensions and thus producing much lower signal and requiring higher spatial resolution) has hitherto remained elusive. In this context, diamond nanostructuring can offer the opportunity to boost the diamond platform sensitivity to the required level. However, a comprehensive analysis of the impact of a nanostructured diamond surface on the neuronal viability and growth was lacking. Here, we pattern a single crystal diamond surface with large-scale nanopillar arrays and we successfully demonstrate growth of a network of living and functional primary mouse hippocampal neurons on it. Our study on geometrical parameters reveals preferential growth along the nanopillar grid axes with excellent physical contact between cell membrane and nanopillar apex. Our results suggest that neuron growth can be tailored on diamond nanopillars to realize a nanophotonic quantum sensing platform for wide-field and label-free neuronal activity recording with sub-cellular resolution
Optically detected magnetic resonance with an open source platform
Localized electronic spins in solid-state environments form versatile and
robust platforms for quantum sensing, metrology and quantum information
processing. With optically detected magnetic resonance (ODMR), it is possible
to prepare and readout highly coherent spin systems, up to room temperature,
with orders of magnitude enhanced sensitivities and spatial resolutions
compared to induction-based techniques, allowing single spin manipulations.
While ODMR was first observed in organic molecules, many other systems are
nowadays intensively being searched for, discovered and studied. Among them is
the nitrogen-vacany (NV) center in diamond. Beyond ODMR it is notably already
widely and successfully used both both as a high-resolution high-sensitivity
quantum sensors for external fields and as a qubit. Others are rare earth ions
used as quantum memories and many other color centers trapped in bulk or
2-dimensional materials. In order to allow the broadest possible community of
researchers and engineers to investigate and develop novel ODMR-based materials
and applications, we overview here the setting up of ODMR experiments using
commercially available hardware. We also present in detail a dedicated
collaborative open-source interface named Qudi and describe the original
features we have added to speed-up data acquisition, relax instrumental
requirements and widen its applicability to individual and ensemble ODMR
systems. Associating hardware and software discussions, this article aims to
steepen the learning curve of newcomers in ODMR from a variety of scientific
backgrounds, to optimize the experimental development time, preempt the common
measurement pitfalls, and to provide an efficient, portable and collaborative
interface to explore innovative experiments.Comment: This material has been submitted to Applied Physics Reviews, 25
Pages, 15 figures, 3 tables, 140 reference