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: The present disclosure relates to a method of making fancy orange synthetic CVD diamond material. Among other things, the method may involve (i) providing a single crystal diamond material that has been grown by CVD and has a [Ns0] concentration less than 5 ppm; (ii) irradiating the provided CVD diamond material so as to introduce isolated vacancies V into at least part of the provided CVD diamond material such that the total concentration of isolated vacancies [VT] in the irradiated diamond material is at least the greater of (a) 0.5 ppm and (b) 50% higher than the [Ns0] concentration in ppm in the provided diamond material; and (iii) annealing the irradiated diamond material to forming vacancy chains from at least some of the introduced isolated vacancies.

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: The present disclosure relates to a method of making fancy orange synthetic CVD diamond material. Among other things, the method may involve (i) providing a single crystal diamond material that has been grown by CVD and has a [Ns0] concentration less than 5 ppm; (ii) irradiating the provided CVD diamond material so as to introduce isolated vacancies V into at least part of the provided CVD diamond material such that the total concentration of isolated vacancies [VT] in the irradiated diamond material is at least the greater of (a) 0.5 ppm and (b) 50% higher than the [Ns0] concentration in ppm in the provided diamond material; and (iii) annealing the irradiated diamond material to forming vacancy chains from at least some of the introduced isolated vacancies.

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 making fancy orange synthetic CVD diamond material is described. The method comprises irradiating a single crystal diamond material that has been grown by CVD to introduce isolated vacancies into at least part of the CVD diamond material and then annealing the irradiated diamond material to form vacancy chains from at least some of the introduced isolated vacancies. Fancy orange CVD diamond material is also described.

Abstract: A method of making fancy pale blue or fancy pale blue/green CVD diamond material is described. The method comprises irradiating single crystal diamond material that has been grown by a CVD process with electrons to introduce isolated vacancies into the diamond material, the irradiated diamond material having (or after a further post-irradiation treatment having) a total vacancy concentration [VT] and a path length L such that [VT]×L is at least 0.072 ppm cm and at most 0.36 ppm cm, and the diamond material becomes fancy pale blue or fancy pale blue/green in color. Fancy pale blue diamonds are also described.

Abstract: Single crystal diamond material produced using chemical vapour deposition (CVD), and particularly diamond material having properties suitable for use in optical applications such as lasers, is disclosed. In particular, a CVD single crystal diamond material having preferred characteristics of longest linear internal dimension, birefringence and absorption coefficient, when measured at room temperature, is disclosed. Uses of the diamond material, including in a Raman laser, and methods of producing the diamond are also disclosed.

Abstract: A method of introducing NV centers in single crystal CVD diamond material is described. One step of the method comprises irradiating diamond material that contains single substitutional nitrogen to introduce isolated vacancies into the diamond material in a concentration of at least 0.05 ppm and at most 1 ppm. Another step of the method comprises annealing the irradiated diamond to form NV centers from at least some of the single substitutional nitrogen defects and the introduced isolated vacancies.

Abstract: A method comprising: selecting a diamond material; irradiating the diamond material to increase toughness and/or wear resistance of the diamond material; and processing the diamond material into one or more diamond tool pieces, wherein the diamond material is selected from the group consisting of: a HPHT diamond material having a total equivalent isolated nitrogen concentration in the range 1 to 600 ppm; a CVD diamond material having a total equivalent isolated nitrogen concentration in the range 0.005 to 100 ppm; and a natural diamond material having a total nitrogen concentration in the range 1 to 2000 ppm, wherein the irradiating comprises controlling energy and dosage of irradiation to provide the diamond material with a plurality of isolated vacancy point defects, the isolated vacancy point defects having a concentration in a range 1×1014 to 1×1021 vacancies/cm?1.

Abstract: A method comprising: selecting a diamond material; irradiating the diamond material with neutrons to increase toughness and/or wear resistance of the diamond material; and processing the diamond material into one or more diamond tool pieces, wherein the irradiating comprises irradiating the diamond material with neutrons having an energy in the range 1.0 keV to 12 MeV, wherein the irradiating comprises controlling energy and dosage of irradiation to provide the diamond material with a plurality of isolated vacancy point defects, the isolated vacancy point defects having a concentration in a range 1×1014 to 1×1020 vacancies/cm?3.

Abstract: A method comprising: selecting a diamond material; irradiating the diamond material with electrons to increase toughness and/or wear resistance of the diamond material; and processing the diamond material into one or more diamond tool pieces, wherein the irradiating comprises controlling energy and dosage of irradiation to provide the diamond material with a plurality of isolated vacancy point defects, the isolated vacancy point defects having a concentration in a range 1×1014 to 1×1022 vacancies/cm?3.

Abstract: A method comprising: selecting a diamond material; irradiating the diamond material to increase toughness and/or wear resistance of the diamond material; and processing the diamond material into one or more diamond tool pieces, wherein the diamond material is selected from the group consisting of: a HPHT diamond material having a total equivalent isolated nitrogen concentration in the range 1 to 600 ppm; a CVD diamond material having a total equivalent isolated nitrogen concentration in the range 0.

Abstract: A method comprising: selecting a diamond material; irradiating the diamond material with electrons to increase toughness and/or wear resistance of the diamond material; and processing the diamond material into one or more diamond tool pieces, wherein the irradiating comprises controlling energy and dosage of irradiation to provide the diamond material with a plurality of isolated vacancy point defects, the isolated vacancy point defects having a concentration in a range 1×1014 to 1×1022 vacancies/cm?3

Abstract: A method comprising: selecting a diamond material; irradiating the diamond material with neutrons to increase toughness and/or wear resistance of the diamond material; and processing the diamond material into one or more diamond tool pieces, wherein the irradiating comprises irradiating the diamond material with neutrons having an energy in the range 1.0 keV to 12 MeV, wherein the irradiating comprises controlling energy and dosage of irradiation to provide the diamond material with a plurality of isolated vacancy point defects, the isolated vacancy point defects having a concentration in a range 1×1014 to 1×1020 vacancies/cm?3.

Abstract: Single crystal diamond material produced using chemical vapour deposition (CVD), and particularly diamond material having properties suitable for use in optical applications such as lasers, is disclosed. In particular, a CVD single crystal diamond material having preferred characteristics of longest linear internal dimension, birefringence and absorption coefficient, when measured at room temperature, is disclosed. Uses of the diamond material, including in a Raman laser, and methods of producing the diamond are also disclosed.

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 making fancy orange synthetic CVD diamond material is described. The method comprises irradiating a single crystal diamond material that has been grown by CVD to introduce isolated vacancies into at least part of the CVD diamond material and then annealing the irradiated diamond material to form vacancy chains from at least some of the introduced isolated vacancies. Fancy orange CVD diamond material is also described.

Abstract: A method of making fancy pale blue or fancy pale blue/green CVD diamond material is described. The method comprises irradiating single crystal diamond material that has been grown by a CVD process with electrons to introduce isolated vacancies into the diamond material, the irradiated diamond material having (or after a further post-irradiation treatment having) a total vacancy concentration [VT] and a path length L such that [VT]×L is at least 0.072 ppm cm and at most 0.36 ppm cm, and the diamond material becomes fancy pale blue or fancy pale blue/green in colour. Fancy pale blue diamonds are also described.

Abstract: A method of introducing NV centres in single crystal CVD diamond material is described. One step of the method comprises irradiating diamond material that contains single substitutional nitrogen to introduce isolated vacancies into the diamond material in a concentration of at least 0.05 ppm and at most 1 ppm. Another step of the method comprises annealing the irradiated diamond to form NV centres from at least some of the single substitutional nitrogen defects and the introduced isolated vacancies.