A method for structuring a decorative or technical pattern in the thickness of an object made of an at least partially transparent amorphous, semi-crystalline or crystalline material, wherein the object is made of an at least partially transparent material including a top surface and a bottom surface which extends away from the top surface. The top or bottom surfaces is provided with a mask defining an opening whose outline corresponds to the profile of the pattern to be structured, the mask covering the top or bottom surface at the positions which are not to be structured. The pattern is structured with a mono- or multicharged ion beam through the opening of the mask, wherein the mechanical properties of the mask are sufficient to prevent the ions of the ion beam from etching the top or bottom surface at the positions where this top or bottom surface is covered by the mask.

An optical element for a deep-ultraviolet light source includes a crystalline substrate; a coating on an exterior surface of the crystalline substrate, the coating having a thickness along a direction that extends away from the exterior surface; and a structure on and/or in the coating, the structure including a plurality of features that extend away from the crystalline substrate along the direction. The features include an amorphous dielectric material and are arranged such that an index of refraction of the structure varies along the direction.

The method of preparing a silicon carbide ingot includes: disposing a raw material and a silicon carbide seed crystal to be separated in a reactor having an internal space; adjusting a temperature, a pressure, and an atmosphere of the internal space for sublimating the raw material and growing the silicon carbide ingot on the silicon carbide seed crystal; and cooling the reactor and retrieving the silicon carbide ingot, wherein the adjusting proceeds in a first inert gas atmosphere having a flow quantity of 100 sccm to 300 sccm, the cooling proceeds in a second inert gas atmosphere having a flow quantity of 1 sccm to 250 sccm, and the reactor has a thermal conductivity of 120 W/mK or less.

The method of preparing a silicon carbide ingot includes: disposing a raw material and a silicon carbide seed crystal to be separated in a reactor having an internal space; adjusting a temperature, a pressure, and an atmosphere of the internal space for sublimating the raw material and growing the silicon carbide ingot on the silicon carbide seed crystal; and cooling the reactor and retrieving the silicon carbide ingot, wherein the adjusting proceeds in a first inert gas atmosphere having a flow quantity of 100 sccm to 300 sccm, the cooling proceeds in a second inert gas atmosphere having a flow quantity of 1 sccm to 250 sccm, and the reactor has a thermal conductivity of 120 W/mK or less.

Kit of parts comprising a synthetic diamond (17), which is accompanied by a slice (9) that was cut off the same original synthetic diamond (7), whereby both the slice (9) and the synthetic diamond 17) are engraved with an identical identification or with an identification which shows that the synthetic diamond (17) and the slice (9) belong together. The kit also comprises an accompanying numbered certificate (12) of authenticity, which refers to the identical identification engraved on the synthetic diamond (17) and the slice (9). The identical identification engraved on the synthetic diamond (17) and the slice (9) comprises the number of the accompanying certificate (12) of authenticity or refers to it.

Kit of parts comprising a synthetic diamond (17), which is accompanied by a slice (9) that was cut off the same original synthetic diamond (7), whereby both the slice (9) and the synthetic diamond 17) are engraved with an identical identification or with an identification which shows that the synthetic diamond (17) and the slice (9) belong together. The kit also comprises an accompanying numbered certificate (12) of authenticity, which refers to the identical identification engraved on the synthetic diamond (17) and the slice (9). The identical identification engraved on the synthetic diamond (17) and the slice (9) comprises the number of the accompanying certificate (12) of authenticity or refers to it.

An SrB.sub.4O.sub.7 or PbB.sub.4O.sub.7 crystal is configured with a plurality of domains with respective periodically alternating polarity of the crystal axis so that the disclosed crystal is capable of quasi-phasematching (QPM). The disclosed crystal is manufactured by a method including patterning a surface of a crystal block of SrB4O7 or PbB4O7, thereby providing patterned uniformly dimensioned regions with a uniform polarity sign on the surface. The method further includes generating a disturbance on the patterned surface, thereby inverting a sign of crystal polarity of every other region to form the SrB.sub.4O.sub.7 or SrB.sub.4O.sub.7 crystal with a plurality of domains with alternating polarity enabling a QPM mechanism.

An SrB.sub.4O.sub.7 or PbB.sub.4O.sub.7 crystal is configured with a plurality of domains with respective periodically alternating polarity of the crystal axis so that the disclosed crystal is capable of quasi-phasematching (QPM). The disclosed crystal is manufactured by a method including patterning a surface of a crystal block of SrB4O7 or PbB4O7, thereby providing patterned uniformly dimensioned regions with a uniform polarity sign on the surface. The method further includes generating a disturbance on the patterned surface, thereby inverting a sign of crystal polarity of every other region to form the SrB.sub.4O.sub.7 or SrB.sub.4O.sub.7 crystal with a plurality of domains with alternating polarity enabling a QPM mechanism.

A silicon carbide ingot producing method is provided. The method produces a silicon carbide ingot in which an internal space of a reactor is depressurized and heated to create a predetermined difference in temperature between upper and lower portions of the internal space. The method produces a silicon carbide ingot in which a plane of a seed crystal corresponding to the rear surface of the silicon carbide ingot is lost minimally. Additionally, the method produces a silicon carbide ingot with few defects and good crystal quality.

A method for making a nanoimprinted perovskite film or a perovskite crystal. The method includes applying a solution onto a substrate, thereby forming a precursor film or a precursor crystal, wherein the solution comprises an organo-metal halide precursor in a solvent. The method also includes fabricating an organo-metal halide perovskite film or an organo-metal halide perovskite crystal, wherein fabricating includes annealing the precursor film or the precursor crystal, thereby at least partially evaporating the solvent. The method also includes imprinting the organo-metal halide perovskite film or the organo-metal halide perovskite crystal with a mold, thereby forming an imprinted film or an imprinted crystal. The method also includes separating the mold from the imprinted film or the imprinted crystal, thereby forming the perovskite film or the perovskite crystal.