Abstract: A system and sensor device for determining geolocation data. A plurality of nodes, each at a predetermined location is provided. Each node emits a time-varying magnetic field, each time-varying magnetic field having a characteristic identifying the node. A sensor device comprises a magnetometer, the magnetometer configured to detect the time-varying magnetic field from at least one of the plurality of nodes, the magnetometer comprising diamond comprising at least one quantum spin defect. The sensor device has a processor configured to determine the identifying characteristic from the sensed time-varying magnetic field, and is further configured to determine geolocation data on the basis of at least the determined identifying characteristic.

Abstract: Single crystal CVD diamond material comprising a total nitrogen concentration of at least 5 ppm and a neutral single substitutional nitrogen, Ns0, to total single substitutional nitrogen, Ns, ratio of at least 0.7. Such a diamond is observed to have a relatively low amount of brown colouration despite the relatively high concentration of nitrogen. A method of making the single crystal diamond is also disclosed, the method including growing the CVD diamond in process gases comprising 60 to 200 ppm nitrogen, in addition to a carbon-containing gas, and hydrogen, wherein the ratio of carbon atoms in the carbon-containing gas to hydrogen atoms in the hydrogen gas is 0.5 to 1.5%.

Abstract: Single crystal CVD diamond material comprising a total nitrogen concentration of at least 5 ppm and a neutral single substitutional nitrogen. Ns0, to total single substitutional nitrogen, Ns, ratio of at least 0.7. Such a diamond is observed to have a relatively low amount of brown colouration despite the relatively high concentration of nitrogen A method of making the single crystal diamond is also disclosed, the method including growing the CVD diamond in process gases comprising 60 to 200 ppm nitrogen, in addition to a carbon-containing gas, and hydrogen, wherein the ratio of carbon atoms in the carbon-containing gas to hydrogen atoms in the hydrogen gas is 0.5 to 1.5%.

Abstract: A synthetic diamond material comprises a surface, wherein the surface comprises a first surface region comprising a first concentration of quantum spin defects. A second surface region has a predetermined area and is located adjacent to the first surface region, the second region comprising a second concentration of quantum spin defects. The first concentration of quantum spin defects is at least ten times greater than the second concentration of quantum spin defects, and at least one of the first or second surface regions comprises chemical vapour deposition, CVD, synthetic diamond. A method of producing the synthetic diamond material is also disclosed.

Abstract: A method for forming a diamond product. Diamond material is provided and a damage layer comprising sp2 bonded carbon is formed in the material. The presence of the damage layer defines a first diamond layer above and in contact with the damage layer and a second diamond layer below and in contact with the damage layer. The damage layer is electrochemically etched to separate it from the first layer, wherein the electrochemical etching is performed in a solution containing ions, the solution having an electrical conductivity of at least 500 ?S cm?1, and wherein the ions are capable of forming radicals during electrolysis. The diamond product is also described.

Abstract: A single crystal diamond material comprising: neutral nitrogen-vacancy defects (NV0); negatively charged nitrogen-vacancy defects (NV?); and single substitutional nitrogen defects (Ns) which transfer their charge to the neutral nitrogen-vacancy defects (NV0) to convert them into the negatively charged nitrogen-vacancy defects (NV), characterized in that the single crystal diamond material has a magnetometry figure of merit (FOM) of at least 2, wherein the magnetometry figure of merit is defined by (I) where R is a ratio of concentrations of negatively charged nitrogen-vacancy defects to neutral nitrogen-vacancy defects ([NV?]/[NV0]), [NV?] is the concentration of negatively charged nitrogen-vacancy defects measured in parts-per-million (ppm) atoms of the single crystal diamond material, [NV0] is a concentration of neutral nitrogen-vacancy defects measured in parts-per-million (ppm) atoms of the single crystal diamond material, and T2? is a decoherence time of the NV? defects, where T2? is T2* for DC magnetome

Abstract: A method of forming a diamond composite body and the diamond composite body. A first single crystal diamond body is provided, which contains nitrogen and has a uniform strain such that over an area of at least 1×1 mm, at least 90 percent of points display a modulus of strain-induced shift of NV resonance of less than 200 kHz, wherein each point in the area is a resolved region of 50 ?m2. The first single crystal diamond body is treated to convert at least some of the nitrogen to form at least 0.3 ppm nitrogen-vacancy, NV?, centres. A CVD process is used to grow a second single crystal diamond body on a surface of the first single crystal diamond body. The second single crystal diamond body has an NV concentration less than or equal to 10 times lower than the NV? concentration in the first single crystal diamond body.

Abstract: Single crystal CVD diamond material comprising a total nitrogen concentration of at least 5 ppm and a neutral single substitutional nitrogen. Ns0, to total single substitutional nitrogen, Ns, ratio of at least 0.7. Such a diamond is observed to have a relatively low amount of brown colouration despite the relatively high concentration of nitrogen A method of making the single crystal diamond is also disclosed, the method including growing the CVD diamond in process gases comprising 60 to 200 ppm nitrogen, in addition to a carbon-containing gas, and hydrogen, wherein the ratio of carbon atoms in the carbon-containing gas to hydrogen atoms in the hydrogen gas is 0.5 to 1.5%.

Abstract: A single crystal CVD diamond material is disclosed, the material comprising a total nitrogen concentration of at least 3 ppm as measured by secondary ion mass spectrometry (SIMS); and a low optical birefringence such that in a sample of the single crystal CVD diamond material having an area of at least 1.3 mm×1.3 mm, and measured using a pixel size of area in a range 1×1 ?m2 to 20×20 ?m2, a maximum value of ?n[average] does not exceed 1.5×10?4, where ?n[average] is an average value of a difference between refractive index for light polarised parallel to slow and fast axes averaged over the sample thickness. A method of making the material is also disclosed.

Abstract: A single crystal diamond material comprising: neutral nitrogen-vacancy defects (NV0); negatively charged nitrogen-vacancy defects (NV?); and single substitutional nitrogen defects (Ns) which transfer their charge to the neutral nitrogen-vacancy defects (NV0) to convert them into the negatively charged nitrogen-vacancy defects (NV), characterized in that the single crystal diamond material has a magnetometry figure of merit (FOM) of at least 2, wherein the magnetometry figure of merit is defined by (I) where R is a ratio of concentrations of negatively charged nitrogen-vacancy defects to neutral nitrogen-vacancy defects ([NV?]/[NV0]), [NV?] is the concentration of negatively charged nitrogen-vacancy defects measured in parts-per-million (ppm) atoms of the single crystal diamond material, [NV0] is a concentration of neutral nitrogen-vacancy defects measured in parts-per-million (ppm) atoms of the single crystal diamond material, and T2? is a decoherence time of the NV? defects, where T2? is T2* for DC magnetome

Abstract: A synthetic diamond material comprises a surface, wherein the surface comprises a first surface region comprising a first concentration of quantum spin defects. A second surface region has a predetermined area and is located adjacent to the first surface region, the second region comprising a second concentration of quantum spin defects. The first concentration of quantum spin defects is at least ten times greater than the second concentration of quantum spin defects, and at least one of the first or second surface regions comprises chemical vapour deposition, CVD, synthetic diamond. A method of producing the synthetic diamond material is also disclosed.

Abstract: Disclosed are synthetic diamond materials for quantum and optical applications, such as quantum information processing, quantum key distribution, quantum repeaters, and quantum sensing devices, based on spin defects in diamond. This includes methods for synthesizing and treating diamond in order to create spin defects with improved spin coherence and optical emission properties, as well as treating the diamond to eliminate unwanted defects that degrade these properties.

Abstract: A method of fabricating fluorescent diamond particles, and diamond particles fabricated by the method. The method comprises mounting a diamond body on a heat sink, the diamond body comprising a plurality of diamond particles having a particle size of no more than 250 micrometres and bound together in the diamond body by a binder. The diamond body is irradiated to generate vacancy defects in the diamond particles. The binder is then removed to separate the diamond body into diamond particles.

Abstract: A method of fabricating fluorescent diamond particles, and diamond particles fabricated by the method. The method comprises mounting a diamond body on a heat sink, the diamond body comprising a plurality of diamond particles having a particle size of no more than 250 micrometres and bound together in the diamond body by a binder. The diamond body is irradiated to generate vacancy defects in the diamond particles. The binder is then removed to separate the diamond body into diamond particles.

Abstract: Disclosed herein are methods of manufacturing synthetic CVD diamond material including orienting and controlling process gas flow in a microwave plasma reactor to improve performance. The microwave plasma reactor includes a gas flow system with a gas inlet comprising one or more gas inlet nozzles disposed opposite the growth surface area and configured to inject process gases towards the growth surface area. The method comprises injecting process gases towards the growth surface area at a total gas flow rate equal to or greater than 500 standard cm3 per minute wherein the process gases are injected into the plasma chamber through the one or more gas inlet nozzles with a Reynolds number in a range 1 to 100.

Abstract: A solid state system comprising a host material and a quantum spin defect, wherein the quantum spin defect has a T2 at room temperature of about 300 ?s or more and wherein the host material comprises a layer of single crystal CVD diamond having a total nitrogen concentration of about 20 ppb or less, wherein the surface roughness, Rq of the single crystal diamond within an area defined by a circle of radius of about 5 ?m centered on the point on the surface nearest to where the quantum spin defect is formed is about 10 nm or less, methods for preparing solid state systems and the use of single crystal diamond having a total nitrogen concentration of about 20 ppb or less in spintronic applications are described.

Abstract: A device for achieving multi-photon interference is provided based on nitrogen-vacancy defects in diamond material. Nitrogen-vacancy defects having a narrow band width and a similar emission frequency are identified within a high quality diamond material. The device has an excitation arrangement configured to individually address nitrogen-vacancy defects and optical outcoupling structures for increasing outcoupling of photons from each nitrogen-vacancy defect. A tuning arrangement is configured to tune the emission from each nitrogen-vacancy defect to reduce differences in frequency and the photons are overlapped. A detector is provided to detect the photon emissions. The detector is configured to resolve sufficiently small differences in photon detection times such that tuned photon emissions from the nitrogen-vacancy defects are quantum mechanically indistinguishable resulting in quantum interference between indistinguishable photon emissions from different nitrogen-vacancy defects.

Abstract: Single crystal diamond having a high chemical purity i.e. a low nitrogen content and a high isotopic purity i.e. a low 13C content, methods for producing the same and a solid state system comprising such single crystal diamond are described.

Abstract: A synthetic single crystal diamond material comprising: a first region comprising electron donor defects; a second region comprising quantum spin defects; and a third region between the first and second regions. The second and third regions have a lower concentration of electron donor defects than the first region. The first and second regions are sufficiently close to allow electrons to be donated from the first region to the second region, thus forming negatively charged quantum spin defects in the second and positively charged defects in the first region, and sufficiently far apart to reduce other coupling interactions between the first and second regions which would otherwise unduly reduce the decoherence time of the plurality of quantum spin defects and/or produce strain broaden of a spectral line width of the plurality of quantum spin defects in the second region.

Abstract: A method of manufacturing an optical element, the method comprising: growing a first layer of single crystal diamond material via a chemical vapor deposition technique using a gas phase having a first nitrogen concentration; growing a second layer of single crystal diamond material over said first layer via a chemical vapor deposition technique using a gas phase having a second nitrogen concentration, wherein the second nitrogen concentration is lower than the first nitrogen concentration; forming an optical element from at least a portion of the second layer of single crystal diamond material; and forming an out-coupling structure at a surface of the optical element for increasing out-coupling of light.