No Arabic abstract
Phosphorus-doped diamond is relevant for applications in sensing, optoelectronics and quantum photonics, since the unique optical properties of color centers in diamond can be combined with the n-type conductivity attained by the inclusion of phosphorus. Here, we investigate the photoluminescence signal of the nitrogen-vacancy and silicon-vacancy color centers in phosphorus-doped diamond as a function of temperature starting from ambient conditions up to about 100$^circ$ Celsius, focusing on the zero-phonon line (ZPL). We find that the wavelength and width of the ZPL of the two color centers exhibit a comparable dependence on temperature, despite the strong difference in the photoluminescence spectra. Moreover, the temperature sensitivity of the ZPL of the silicon-vacancy center is not significantly affected by phosphorus-doping, as we infer by comparison with silicon-vacancy centers in electronic-grade single-crystal diamond.
The photoluminescence of nitrogen-vacancy (NV) centers in diamond nanoparticles exhibits specific properties as compared to NV centers in bulk diamond. For instance large fluctuations of lifetime and brightness from particle to particle have been reported. It has also been observed that for nanocrystals much smaller than the mean luminescence wavelength, the particle size sets a lower threshold for resolution in Stimulated Emission Depletion (STED) microscopy. We show that all these features can be quantitatively understood by realizing that the absorption-emission of light by the NV center is mediated by the diamond nanoparticle which behaves as a dielectric nanoantenna.
We show a marked reduction in the emission from nitrogen-vacancy (NV) color centers in single crystal diamond due to exposure of the diamond to hydrogen plasmas ranging from 700{deg}C to 1000{deg}C. Significant fluorescence reduction was observed beneath the exposed surface to at least 80mm depth after ~10 minutes, and did not recover after post-annealing in vacuum for seven hours at 1100{deg}C. We attribute the fluorescence reduction to the formation of NVH centers by the plasma induced diffusion of hydrogen. These results have important implications for the formation of nitrogen-vacancy centers for quantum applications, and inform our understanding of the conversion of nitrogen-vacancy to NVH, whilst also providing the first experimental evidence of long range hydrogen diffusion through intrinsic high-purity diamond material.
Diamond nitrogen-vacancy (NV) center magnetometry has recently received considerable interest from researchers in the fields of applied physics and sensors. The purpose of this review is to analyze the principle, sensitivity, technical development potential, and application prospect of the diamond NV center magnetometry. This review briefly introduces the physical characteristics of NV centers, summarizes basic principles of the NV center magnetometer, analyzes the theoretical sensitivity, and discusses the impact of technical noise on the NV center magnetometer. Furthermore, the most critical technologies that affect the performance of the NV center magnetometer are described: diamond sample preparation, microwave manipulation, fluorescence collection, and laser excitation. The theoretical and technical crucial problems, potential solutions and research technical route are discussed. In addition, this review discusses the influence of technical noise under the conventional technical conditions and the actual sensitivity which is determined by the theoretical sensitivity and the technical noise. It is envisaged that the sensitivity that can be achieved through an optimized design is in the order of 10 fT/Hz^1/2. Finally, the roadmap of applications of the diamond NV center magnetometer are presented.
Silicon-vacancy (SiV) centers in diamond are promising systems for quantum information applications due to their bright single photon emission and optically accessible spin states. Furthermore, SiV centers in low-strain diamond are insensitive to pertubations of the dielectric environment, i.e. they show very weak spectral diffusion. This property renders ensembles of SiV centers interesting for sensing applications. We here report on photoluminescence excitation (PLE) spectroscopy on an SiV ensemble in a low strain, CVD-grown high quality diamond layer, where we measure the fine structure with high resolution and obtain the linewidths and splittings of the SiV centers. We investigate the temperature dependence of the width and position of the fine structure peaks. Our measurements reveal linewidths of about 10 GHz as compared to a lifetime limited width on the order of 0.1 GHz. This difference arises from the inhomogeneous broadening of the transitions caused by residual strain. To overcome inhomogeneous broadening we use spectral hole burning spectroscopy which enables us to measure a nearly lifetime limited homogeneous linewidth of 279 MHz. Furthermore, we demonstrate evidence of coherent interaction in the system by driving a $Lambda$-scheme. Additional measurements on single emitters created by ion implantation confirm the homogeneous linewidths seen in the spectral hole burning experiments and relate the ground state splitting to the decoherence rate.
The negatively charged nitrogen-vacancy (NV-) center in diamond is an attractive candidate for applications that range from magnetometry to quantum information processing. Here we show that only a fraction of the nitrogen (typically < 0.5 %) incorporated during homoepitaxial diamond growth by Chemical Vapor Deposition (CVD) is in the form of undecorated NV- centers. Furthermore, studies on CVD diamond grown on (110) oriented substrates show a near 100% preferential orientation of NV- centers along only the [111] and [-1-11] directions, rather than the four possible orientations. The results indicate that NV centers grow in as units, as the diamond is deposited, rather than by migration and association of their components. The NV unit of the NVH- is similarly preferentially oriented, but it is not possible to determine whether this defect was formed by H capture at a preferentially aligned NV center or as a complete unit. Reducing the number of NV orientations from 4 orientations to 2 orientations should lead to increased optically-detected magnetic resonance contrast and thus improved magnetic sensitivity in ensemble-based magnetometry.