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 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: There is described a single crystal CVD diamond material comprising three orthogonal dimensions of at least 2 mm; one or more regions of low optical birefringence, indicative of low strain, such that in a sample of the single crystal CVD diamond material having a thickness in a range 0.5 mm to 1.0 mm and an area of greater than 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 for the one or more regions of low optical birefringence, 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; one or more regions of high optical birefringence, indicative of high strain, such that in said sample of the single crystal CVD diamond material and measured using said pixel size, ?n[average] is greater than 1.5×10?4 and less than 3×10?3; and is wherein every 1.3 mm×1.

Abstract: There is described a single crystal CVD diamond material comprising three orthogonal dimensions of at least 2 mm; one or more regions of low optical birefringence, indicative of low strain, such that in a sample of the single crystal CVD diamond material having a thickness in a range 0.5 mm to 1.0 mm and an area of greater than 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 for the one or more regions of low optical birefringence, 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; one or more regions of high optical birefringence, indicative of high strain, such that in said sample of the single crystal CVD diamond material and measured using said pixel size, ?n[average] is greater than 1.5×10?4 and less than 3×10?3; and is wherein every 1.3 mm×1.

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 single crystal CVD synthetic diamond layer comprising a non-parallel dislocation array, wherein the non-parallel dislocation array comprises a plurality of dislocations forming an array of inter-crossing dislocations, as viewed in an X-ray topographic cross-sectional view or under luminescent conditions.

Abstract: A single crystal CVD synthetic diamond material comprising: a total as-grown nitrogen concentration equal to or greater than 5 ppm, and a uniform distribution of defects, wherein said uniform distribution of defects is defined by one or more of the following characteristics: (i) the total nitrogen concentration, when mapped by secondary ion mass spectrometry (SIMS) over an area equal to or greater than 50×50 ?m using an analysis area of 10 ?m or less, possesses a point-to-point variation of less than 30% of an average total nitrogen concentration value, or when mapped by SIMS over an area equal to or greater than 200×200 ?m using an analysis area of 60 ?m or less, possesses a point-to-point variation of less than 30% of an average total nitrogen concentration value; (ii) an as-grown nitrogen-vacancy defect (NV) concentration equal to or greater than 50 ppb as measured using 77K UV-visible absorption measurements, wherein the nitrogen-vacancy defects are uniformly distributed through the synthetic single cryst

Abstract: Starting from a diamond material which shows a difference in its absorption characteristics after exposure to radiation with an energy of at least 5.5 eV (typically UV radiation) and thermal treatment at 798K, controlled irradiation is applied so as to introduce defects in the diamond material. After the controlled irradiation the difference in the absorption characteristics after exposure to radiation with an energy of at least 5.5 eV and thermal treatment at 798K is reduced.

Abstract: A method of producing a grown single crystal diamond substrate comprising: (a) providing a first diamond substrate which presents a (001) major surface, which major surface is bounded by at least one <100> edge, the length of the said at least one <100> edge exceeding any dimension of the surface that is orthogonal to the said at least one <100> edge by a ratio of at least 1.3:1; and (b) growing diamond material homoepitaxially on the (001) major surface of the diamond material surface under chemical vapour deposition (CVD) synthesis conditions, the diamond material growing both normal to the major (001) surface, and laterally therefrom.

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 single crystal CVD synthetic diamond material comprising: a total as-grown nitrogen concentration equal to or greater than 5 ppm, and a uniform distribution of defects, wherein said uniform distribution of defects is defined by one or more of the following characteristics: (i) the total nitrogen concentration, when mapped by secondary ion mass spectrometry (SIMS) over an area equal to or greater than 50×50 ?m using an analysis area of 10 ?m or less, possesses a point-to-point variation of less than 30% of an average total nitrogen concentration value, or when mapped by SIMS over an area equal to or greater than 200×200 ?m using an analysis area of 60 ?m or less, possesses a point-to-point variation of less than 30% of an average total nitrogen concentration value; (ii) an as-grown nitrogen-vacancy defect (NV) concentration equal to or greater than 50 ppb as measured using 77K UV-visible absorption measurements, wherein the nitrogen-vacancy defects are uniformly distributed through the synthetic single cryst

Abstract: A single crystal CVD synthetic diamond layer comprising a non-parallel dislocation array, wherein the non-parallel dislocation array comprises a plurality of dislocations forming an array of inter-crossing dislocations, as viewed in an X-ray topographic cross-sectional view or under luminescent conditions.

Abstract: A method of producing a grown single crystal diamond substrate comprising: (a) providing a first diamond substrate which presents a (001) major surface, which major surface is bounded by at least one <100> edge, the length of the said at least one <100> edge exceeding any dimension of the surface that is orthogonal to the said at least one <100> edge by a ratio of at least 1.3:1; and (b) growing diamond material homoepitaxially on the (001) major surface of the diamond material surface under chemical vapour deposition (CVD) synthesis conditions, the diamond material growing both normal to the major (001) surface, and laterally therefrom.

Abstract: Starting from a diamond material which shows a difference in its absorption characteristics after exposure to radiation with an energy of at least 5.5 eV (typically UV radiation) and thermal treatment at 798K, controlled irradiation is applied so as to introduce defects in the diamond material. After the controlled irradiation the difference in the absorption characteristics after exposure to radiation with an energy of at least 5.5 eV and thermal treatment at 798K is reduced.