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 synthetic diamond material using a microwave plasma activated chemical vapour deposition technique is provided which utilizes high and uniform microwave power densities applied over large areas and for extended periods of time. Products fabricated using such a synthesis technique are described including a single crystal CVD diamond layer which has a large area and a low nitrogen concentration, and a high purity, fast growth rate single crystal CVD diamond material.

Abstract: A device that utilises an electronic Zeeman splitting effect comprises a solid-state material that comprises at least one spin defect, a magnetic field generator configured to generate a bias magnetic field, and a compensation system to compensate for an effect of changes in temperature on the bias magnetic field. The compensation system comprises a temperature sensor configured to measure any of a temperature and a change in temperature of the magnetic field generator, and a computer device configured to determine a change in the bias magnetic field as a result of a change in the measured temperature or the measured change in temperature. The computer device is further configured to adjust a predetermined bias magnetic field value using the determined change in bias magnetic field and using the value as an input to the compensation system to compensate for the effect of changes in temperature on the bias magnetic field.

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: 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 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 method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 107 cm?2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

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 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: A method of fabricating a polycrystalline CVD synthetic diamond wafer is disclosed. A first polycrystalline CVD synthetic diamond wafer is grown using a CVD process to a first thickness on a substrate. A second smaller wafer is cut from the polycrystalline CVD synthetic diamond wafer. The second smaller wafer is located on a carrier, and further polycrystalline CVD synthetic diamond material is grown on the second smaller wafer to a second thickness to give a polycrystalline CVD synthetic diamond material having a total thickness of the combined first and second thicknesses.

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 polycrystalline CVD synthetic diamond material is provided that has an average thermal conductivity at room temperature through a thickness of the polycrystalline CVD synthetic diamond material of between 1700 and 2400 Wm?1K?1, a thickness of at least 2.5 mm and a visible transmittance through the thickness of the polycrystalline CVD synthetic diamond of at least 25%. A wafer comprising the material is also provided, wherein at least 70% of a total area of the wafer has the properties of the polycrystalline CVD synthetic diamond material. A method for fabricating the wafer is also disclosed.

Abstract: A bonded diamond assembly and a method of forming the assembly. The assembly comprises a polycrystalline diamond wafer having a largest linear dimension of between 25 mm and 200 mm, a substrate and a bonding layer located between the diamond and the substrate and bonding them together. The bonding layer, when inspected using ultrasound using a resolution of 50 ?m, a focal length selected to inspect the bonding layer, and frequencies of 100 MHz and 30 MHz, comprises low numbers of voids extending either across the thickness of the bonding layer and low numbers of voids that do not extend across the thickness of the bonding layer.

Abstract: A non-planar chemical vapour deposition polycrystalline diamond body has a dome body having an apex and an outer periphery. The dome body has an average radius of curvature in a range of 4 mm to 25 mm and a maximum linear dimension at the outer periphery of the dome body of no more than 26 mm. The average radius of curvature is no less than 0.6 times the maximum linear dimension at the outer periphery. A method of fabricating the non-planar diamond body is also disclosed.

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 coloured single crystal CVD synthetic diamond material comprising: a plurality of layers, wherein the plurality of layers includes at least two sets of layers which differ in terms of their defect composition and colour, wherein defect type, defect concentration, and layer thickness for each of the at least two sets of layers is such that if the coloured single crystal CVD diamond material is fabricated into a round brilliant cut diamond comprising a table and a culet, and having a table to culet depth greater than 1 mm, the round brilliant cut diamond comprises a uniform colour as viewed by naked human eye under standard ambient viewing conditions in at least a direction through the table to the culet.

Abstract: A method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 107cm?2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

Abstract: A method of manufacturing synthetic diamond material using a chemical vapour deposition process, and a diamond obtained by such a method are described. The method comprises providing a freestanding synthetic single crystal diamond substrate wafer having a dislocation density of at least 107 cm?2. The synthetic single crystal diamond substrate wafer is located over a substrate holder within a chemical vapour deposition reactor. Process gases are fed into the reactor, the process gases including a gas comprising carbon. Crack-free synthetic diamond material is grown on a surface of the single crystal diamond substrate wafer at a temperature of at least 900° C. to a thickness of at least 0.5 mm and with lateral dimensions of at least 4 mm by 4 mm.

Abstract: A diamond lens (3) configured for use in a multispectral imaging system (1). The diamond lens (3) has a largest linear dimension of at least 10 mm and is formed from diamond material having a birefringence An of greater than 1×10?4, measured over a specified area of at least 4 mm by 4 mm through a maximum thickness of at least 400 ?m. A multispectral imaging system (1) comprising the diamond lens (3) and a component (2) comprising the diamond lens are also described.