Abstract: A method includes: providing a plate-like glass element having side faces and an ultrashort pulse laser having a laser beam; directing the laser beam onto one of the side faces; concentrating the laser beam by focusing optics to form an elongated focus in the glass element; producing a filament-shaped flaw in a volume of the glass element by a radiated-in energy of the laser beam, a longitudinal direction of which runs transverse to one of the side faces, and the ultrashort pulse laser radiates in a pulse or a pulse packet having at least two successive laser pulses to produce the filament-shaped flaw; widening the filament-shaped flaw to form a channel by exposing the glass element to an etching including an etching medium which removes glass at a rate of less than 8 ?m per hour; and introducing rounded, hemispherical depressions in a wall of the channel by the etching.

Abstract: A plate-like glass element includes a pair of opposite side faces and an opening having a transverse dimension of at least 200 ?m. The opening is delimited by an edge. The edge has a plurality of rounded, substantially hemispherical depressions that adjoin one another. The plurality of rounded, substantially hemispherical depressions having abutting concave roundings which form ridges.

Abstract: A plate-like glass element including a pair of opposite side faces and at least one channel introduced into the glass of the glass element. The at least one channel joins the side faces and opens into the side faces. The at least one channel has a rounded wall and a transverse dimension of less than 100 ?m. The at least one channel extends in a longitudinal direction that runs transverse to the side faces. The rounded wall of the at least one channel has a plurality of rounded, substantially hemispherical depressions.

Abstract: A plate-like glass element including a pair of opposite side faces and at least one channel introduced into the glass of the glass element. The at least one channel joins the side faces and opens into the side faces. The at least one channel has a rounded wall and a transverse dimension of less than 100 ?m. The at least one channel extends in a longitudinal direction that runs transverse to the side faces. The rounded wall of the at least one channel has a plurality of rounded, substantially hemispherical depressions.

Abstract: The scintillation material has a maximum oxygen content of 2,500 ppm and is a compound of formula LnX3 or LnX3:D, wherein Ln is at least one rare earth element, X is F, Cl, Br, or I; and D is at least one cationic dopant of one or more of the elements Y, Zr, Pd, Hf and Bi and, if present, is present in an amount of 10 ppm to 10,000 ppm. The process of making the scintillation material includes optionally mixing the compound of the formula LnX3 with the at least one cationic dopant, heating the compound or the mixture so obtained to a melting temperature to form a melt, adding one or more carbon halides and then cooling the melt to form a crystal or crystalline structure. The maximum oxygen content of the scintillation material is preferably 1000 ppm.

Abstract: The method produces low-stress, large-volume crystals with low birefringence and uniform index of refraction. The method includes growing the crystal with larger than desired dimensions including diameter and height from a melt; cooling and tempering the crystal with the larger than desired dimensions and after the cooling and tempering removing edge regions of the crystal with the larger than desired dimensions so that a diameter reduction and a height reduction of at least five percent occurs respectively and so that the crystal has the desired dimensions of diameter and height. No further tempering takes place after removing of the edge regions.

Abstract: The method of making uniform low-stress crystals includes immersing a seed crystal held at a temperature under its melting point in a melt in a crucible and drawing it from the melt. The crystal and/or melt are rotated relative to each other and a planar phase boundary surface is maintained between them by detecting a surface temperature of the melt and/or crystal and controlling temperature fluctuations by increasing or decreasing the rotation speed. A low-stress crystal of formula: (A1-xDx)3Al5O12 wherein 0<x<1, A=Lu and D=Pr and/or Ce, is preferred. These crystals have an index of refraction uniformity ?n of <1 ppm and a stress birefringence of <1 nm/cm at 193 nm, so that they are suitable for making optical elements for DUV lithography.

Abstract: The scintillation material has a maximum oxygen content of 2,500 ppm and is a compound of formula LnX3 or LnX3:D, wherein Ln is at least one rare earth element, X is F, Cl, Br, or I; and D is at least one cationic dopant of one or more of the elements Y, Zr, Pd, Hf and Bi and, if present, is present in an amount of 10 ppm to 10,000 ppm. The process of making the scintillation material includes optionally mixing the compound of the formula LnX3 with the at least one cationic dopant, heating the compound or the mixture so obtained to a melting temperature to form a melt, adding one or more carbon halides and then cooling the melt to form a crystal or crystalline structure. The maximum oxygen content of the scintillation material is preferably 1000 ppm.

Abstract: The scintillation material is a compound of the general formula LnX3:D, in which Ln is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and/or Lu; X is F, Cl, Br or I, and D is at least one cation of elements Y, Zr, Pd, Hf and Bi as dopant and is contained in the material in an amount of 10 ppm to 10,000 ppm. When the scintillation material includes the preferred CeBr3 and Bi as a cationic dopant, it also includes at least one other cation of the elements Y, Zr, Pd and Hf. The scintillation material may be in single crystal or polycrystalline form.

Abstract: A large-volume scintillation crystal affording a high scintillation yield and having high mechanical strength is obtained by growing a crystal from a melt containing strontium iodide, barium iodide or a mixture thereof and by doping with an activator. To this end, the melt is enclosed in a closed volume. Before and/or during the growing, the melt is in diffusion-permitting connection, via the enclosed volume, with an oxygen getter which sets a constant oxygen potential in the closed volume and the melt. Such a scintillation crystal is suitable for detecting UV-, gamma-, beta-, alpha- and/or positron radiation.

Abstract: The process produces a scintillation material of formula LnX3 or LnX3:D, wherein Ln is at least one rare earth element, X is F, Cl, Br, or I; and D is at least one cationic dopant selected from the group consisting of Y, Zr, Pd, Hf and Bi. The at least one cationic dopant is present in the scintillation material in an amount of 10 ppm to 10,000 ppm. The process includes optionally mixing the compound of the general empirical formula LnX3 with the at least one cationic dopant, heating the compound or the mixture obtained by the optional mixing to a melting temperature thereof, then growing the crystal or crystalline structure and cooling the resulting crystal or crystalline structure from a growing temperature to a temperature of 100° C. at a cooling rate of less than 20 K/h.

Abstract: The process for growing a rare earth aluminum or gallium garnet crystal from a melt includes melting an aluminum or gallium garnet of at least one rare earth, preferably Lu or Y, or a mixture of oxides of formula Me2O3, wherein Me represents the rare earth or aluminum or gallium. The melt also includes a fluoride anion acting as a counter ion for the rare earth and the aluminum or gallium. The components comprising the rare earth and aluminum or gallium are introduced in the melt so that the amounts of the rare earth and aluminum or gallium are defined by the formula: SE(3-x)X(5-y)O(12-2x-2y)F(x+y), wherein 0?x?0.2 and 0?y?0.2 and 0<x+y?0.4, and X is aluminum or gallium. The resulting crystals are used for optical elements at 193 nm, such as lenses, and as scintillation materials.

Abstract: Homogeneity residuals of the refractive index have a strong influence on the performance of lithography tools for both 193 and 157 nm application wavelengths. By systematic investigations of various defects in the real structure of CaF2 crystals, the origin of homogeneity residuals can be shown. Based on a quantitative analysis we define limiting values for the individual defects which can be either tolerated or controlled by optimized process steps, e.g. annealing. These correlations were carried out for all three relevant main crystal lattice orientations of CaF2 blanks. In conclusion we achieved a strong improvement of the critical parameters of both refractive index homogeneity and striae for large size lens blanks up to 270 mm diameter.

Abstract: A process and a device is described to avoid the depolarization of linear-polarized light during the transmission of light through crystals exhibiting a {111} or {100} crystal plane, respectively, and a <100> or <111> crystal axis, respectively. The device is characterized in that the linear-polarized light meets the surface of the crystals in an angle of 45-75°, whereby the surface is formed by the {111} or the {100} plane. The crystal is arranged in such a way that upon entering the crystal, the light spreads along the <100> or <111> crystal axis, respectively, as parallel as possible, and/or that the device comprises a unit for temperature equalization to avoid a thermal gradient in the crystal.

Abstract: The method of making uniform low-stress crystals includes immersing a seed crystal held at a temperature under its melting point in a melt in a crucible and drawing it from the melt. The crystal and/or melt are rotated relative to each other and a planar phase boundary surface is maintained between them by detecting a surface temperature of the melt and/or crystal and controlling temperature fluctuations by increasing or decreasing the rotation speed. The single crystals obtained by this method have a diameter ?50 mm and no visible growth strips in a fishtail pattern when a 2-mm thick sample is observed between crossed polarizers. These crystals have an index of refraction uniformity ?n of <1 ppm and a stress birefringence of <1 nm/cm at 193 nm, so that optical elements suitable for DUV lithography can be made from them.

Abstract: The method of making a single crystal, especially a CaF2 single crystal, includes tempering, in which the crystal is heated at <18 K/h to a temperature of 1000° C. to 1350° C. and held at this temperature for at least 65 hours with maximum temperature differences within the crystal of <0.2 K. Subsequently the crystal is cooled with a cooling rate of at maximum 0.5 K/h above a limiting temperature between 900° C. to 600° C. and then further below this limiting temperature at maximum 3 K/h. The obtained CaF2 crystals have refractive index uniformity <0.025×10?6 (RMS) in a (111)-, (100)- or (110)-direction and a stress birefringence of less than 2.5 nm/cm (PV) and/or a stress birefringence of less than 1 nm/cm (RMS) in the (100)- or (110)-direction. In the (111)-direction the stress birefringence is <0.5 nm/cm (PV) and/or the stress birefringence is <0.15 nm/cm (RMS).

Abstract: An optical material for lithographic applications is selected from crystal materials by a testing method. The crystal materials are preferably quartz and/or alkali or alkaline earth halides, especially fluorides, or mixed crystals. The testing method includes three tests to measure irreversible radiation damage: 1) the optical material is irradiated with ultraviolet radiation at 193 nm and the non-intrinsic fluorescence intensity at 740 nm is measured; 2) the optical material is irradiated with high energy density laser light and a change in respective absorptions before and after irradiation at 385 nm is measured; and 3) the optical material is irradiated with an X-ray or radioactive source to form all possible color centers and a difference of respective surface integrals of corresponding absorption spectra in ultraviolet spectral and/or visible spectral regions is measured before and after irradiation.

Abstract: The crucible for receiving a melt of a high-melting material has a refractory metal layer that has a melting point of at least 1800° C., which covers a part of the surface of the crucible that would otherwise come in contact with the melt. The refractory metal preferably has a thickness of less than 1 mm. It is either a coating deposited on the surface of the crucible or is a loosely connected foil applied to the surface of the crucible.

Abstract: A method of selecting suitable laser-stable optical material for making an optical element, especially for transmission at wavelengths under 200 nm, is described. It includes a first pre-irradiation to produce radiation damage, subsequent excitation of induced fluorescence with light at between 350 to 700 nm at least ten minutes after the first pre-irradiation and measurement of induced fluorescence intensities at one or more wavelengths between 550 nm and 810 nm. After the fluorescence intensity measurement a second pre-irradiation is performed with an at least 1000-fold higher energy than in the first pre-irradiation and then induced fluorescence intensities are again measured to determine the increase in the fluorescence intensities.

Abstract: The method determines laser stability of an optical material, which is suitable for making an optical element through which high-energy light passes. The method includes pre-irradiation to produce radiation damage and measurement of the resulting induced non-intrinsic fluorescence. The method is distinguished by excitation of induced fluorescence immediately after pre-irradiation and after at least ten minutes after pre-irradiation with light of a wavelength between 350 and 810 nm, and measurement and quantitative evaluation of fluorescence intensities at wavelengths between 550 nm and 810 nm. Especially laser-stable optical materials, particularly CaF2 crystals, have a normalized difference (Z) of the fluorescence intensities measured at a first time immediately after pre-irradiation and at a second time at least ten minutes after the pre-irradiation, as calculated by the following equation (1): Z=(I2,?1,?2?I1,?1,?2)I2,?1,?2??(1), which is less than 0.3.