Abstract:
PROBLEM TO BE SOLVED: To provide a method for determining the optical quality of a fluoride single crystal and to provide a method of making a fluoride crystal optical element used at shorter wavelengths than SOLUTION: The method includes: (a) a step of irradiating at least one volume element of the fluoride single crystal, along at least one given family of crystalline planes with a hard X-ray beam in order to obtain a picture of the diffraction in the transmission mode of the hard X-rays across this at least one volume element along this at least one family of crystalline planes; (b) a step of studying the picture obtained in step (a); and (c) a step of calculating the mosaicity of the at least one volume element along the at least one family of crystalline planes from the study of step (b). COPYRIGHT: (C)2003,JPO
Abstract:
A low lead impurity level in a below 200 nm transmitting optical fluoride crystal is determined by transmitting a transmission test wavelength of 200-210 nm through below 200 nm wavelength transmitting optical fluoride crystal light transmission path length and measuring the transmission of the 200-210 nm test wavelength to provide a lead ppb impurity level measurement less than 900 ppb. Detection of a low lead impurity level in a below 200 nm transmitting optical fluoride crystal, comprises providing a below 200 nm wavelength transmitting optical fluoride crystal (20) having a crystal light transmitting path length (21). The below 200 nm wavelength transmits optical fluoride crystal light transmission path length \-2 mm. A light transmission spectrophotometer is provided having a lamp for producing a transmission test wavelength of 200-210 nm and a transmission detector (28) for measuring transmission of the test wavelength. The transmission test wavelength of 200-210 nm is transmitted through below 200 nm wavelength transmitting optical fluoride crystal light transmission path length and measuring the transmission of the 200-210 nm test wavelength through the path length to provide a lead ppb impurity level measurement less than 900 ppb. An Independent claim is also included for a method of making a below 200 nm wavelength optical element having an absorption coefficient at 200-210 nm of less than 0.0017 cm .
Abstract:
The present invention has the following objectives: polycrystalline alkali-metal or alkaline-earth metal (more particularly CaF2) fluorides, produced in an original form, namely in the form of beads; said beads having a diameter or equivalent diameter greater than or equal to 100 mum, advantageously between 100 mum and 2 cm and an apparent density greater than or equal to 60%, advantageously at least 90% of the theoretical density of said fluoride; a process for the preparation (the conditioning) of said fluorides; a process for the preparation of single crystals of the corresponding alkali-metal or alkaline-earth metal fluorides that uses polycrystalline fluorides in the aforementioned original form.
Abstract:
The present invention has the following objectives: polycrystalline alkali-metal or alkaline-earth metal (more particularly CaF2) fluorides, produced in an original form, namely in the form of beads; said beads having a diameter or equivalent diameter greater than or equal to 100 mu m, advantageously between 100 mu m and 2 cm and an apparent density greater than or equal to 60 %, advantageously at least 90 % of the theoretical density of said fluoride; a process for the preparation (the conditioning) of said fluorides; a process for the preparation of single crystals of the corresponding alkali-metal or alkaline-earth metal fluorides that uses polycrystalline fluorides in the aforementioned original form.
Abstract:
Determination of the optical quality of a fluoride monocrystal comprises: (a) irradiation of at least one volume element of the monocrystal, following at least one family of crystalline planes by a beam of hard X-rays to obtain a diffraction image in transmission mode of the X-rays crossing the volume element along the family of crystalline planes; (b) studying the image produced; (c) calculating the mosaicity of the volume element along the family of crystalline planes from this study. An Independent claim is also included for an optical element for utilization in projection systems operating at wavelengths of between 100 and 200 nm using a fluoride monocrystal with a mosaicity of less than 10 s.
Abstract:
The present invention has the following objectives: polycrystalline alkali-metal or alkaline-earth metal (more particularly CaF2) fluorides, produced in an original form, namely in the form of beads; said beads having a diameter or equivalent diameter greater than or equal to 100 mum, advantageously between 100 mum and 2 cm and an apparent density greater than or equal to 60%, advantageously at least 90% of the theoretical density of said fluoride; a process for the preparation (the conditioning) of said fluorides; a process for the preparation of single crystals of the corresponding alkali-metal or alkaline-earth metal fluorides that uses polycrystalline fluorides in the aforementioned original form.