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 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: 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 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: 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.