Izumitani, T.
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1985
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1985
AbstractAbstract
[en] It is well known that Pt inclusion in laser glass remarkably lowers the damage threshold by laser beam. Present commercial laser glasses are produced so as to minimize the Pt inclusion. However, the damage due to small Pt inclusion, which has never seriously caused the laser damage in a lower fluence level, is getting to be a problem as the output fluence of laser increases. In NOVA system, most of laser glasses were damaged at fluence of 3 to 4 J/cm2. Since NOVA has been planned to operate at 10 J/cm2, this damage threshold is absolutely unacceptable and it should be increased. In this report we will show the basic conception to make a Pt inclusion free glass and its experimental results
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15 Jul 1985; 20 p; Available from NTIS, PC A02/MF A01; 1 as DE87008161; Portions of this document are illegible in microfiche products.
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Asahara, Y.; Izumitani, T.
Hoya Corp., Tokyo (Japan)1979
Hoya Corp., Tokyo (Japan)1979
AbstractAbstract
[en] Gradient refractive index antireflection films are produced by a chemical etch/leach process applied to phase separable glass ARG 2, optical quality, of which would be easily obtained. The reflectance (one surface) is effectively reduced from 4.05% to lower than 0.5% in the wavelength regime 0.4 to 1.4μ. This laser damage threshold is 11.5 +- 1.5 J/cm2, indicating that ARG 2 is available for the optical component in high power laser system such as spatial filter lenses
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27 Nov 1979; 10 p; Available from NTIS., PC A02/MF A01
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Izumitani, T.; Meissner, H.E.; Toratani, H.
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1986
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1986
AbstractAbstract
[en] The objectives of this project have been: (1) Investigate the possibility of chemical etching of GSGG crystal slabs to obtain increased strength. (2) Design and construct a simplified mold assembly for casting cladding glass to the edges of crystal slabs of different dimensions. (3) Conduct casting experiments to evaluate the redesigned mold assembly and to determine stresses as function of thermal expansion coefficient of cladding glass. (4) Clad larger sizes of GGG slabs as they become available. These tasks have been achieved. Chemical etching of GSGG slabs does not appear possible with any other acid than H3PO4 at temperatures above 3000C. A mold assembly has been constructed which allowed casting cladding glass around the edges of the largest GGG slabs available (10 x 20 x 160 mm) without causing breakage through the annealing step
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15 Nov 1986; 12 p; Available from NTIS, PC A02/MF A01; 1 as DE87008163; Portions of this document are illegible in microfiche products.
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Nakajima, Y.; Izumitani, T.
Hoya Corp., Tokyo (Japan); Hoya Optics U.S.A., Inc., Menlo Park, CA1980
Hoya Corp., Tokyo (Japan); Hoya Optics U.S.A., Inc., Menlo Park, CA1980
AbstractAbstract
[en] Effects of substrate laser glass on the damage threshold and adhesion of dielectric films has been studied in order to improve the damage threshold. The study is divided into two parts: the first part dealing with four types of laser glass, LSG-91H silicate, LHG-8 phosphate, P-1 phosphate and LHG-10 fluorophosphate; the second part dealing with twenty-six glasses with systematically modified compositions in three glass systems, silicate, phosphate and fluorophosphate
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1980; 27 p; Available from NTIS., PC A03/MF A01
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Izumitani, T.; Toratani, H.; Meissner, H.E.
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1987
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1987
AbstractAbstract
[en] The objective of this work was a process development on making a laser glass with loss coefficient of 10-4cm-1 at 1.05μ. The key issues for making such a low loss glass will be to use pure raw materials, to reduce OH content and to prevent contamination from the melting environment. A sublimation method was tried to prepare pure P2O5 batch material. In an attempt to distinguish contributions to the overall loss, glasses were melted in furnaces which were controlled in moisture as well as contamination. Evaluation of glass samples at LLNL are expected to provide guidance on the importance of various process parameters. A new 0.5 liter furnace which almost completely prevents contamination by the furnace environment has been constructed to obtain useful information for making a low loss glass on a production scale
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15 Jan 1987; 25 p; Available from NTIS, PC A02/MF A01; 1 as DE87008162; Portions of this document are illegible in microfiche products.
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Izumitani, T.; Toratani, H.; Meissner, H.E.
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1986
Hoya Optics, Inc., Fremont, CA (USA); Lawrence Livermore National Lab., CA (USA)1986
AbstractAbstract
[en] The objective of this work is to evaluate the suitability of Pt alloys as crucible materials for melting LHG-8 phosphate laser glass. The tendency of forming metallic inclusions and ionic dissolution of alloy components in the glass is to be compared with that of pure Pt. Ionic Pt is introduced into the glass melt by direct dissolution of Pt at the crucible-melt interface and by vapor phase transport. It was felt that a Pt-alloy may behave sufficiently differently from Pt that a number of alloys should be studied. Pt inclusions may originate from Pt which reprecipitates from the glass melt on cooling or change in redox-conditions; from volatilized Pt which deposits in colder zones of the melting environment as crystallites which may drop back into the glass melt; and/or from Pt particles which are mechanically removed from the crucible and drop into the glass melt. Besides pure Pt, the following alloys have been tested: Pt/10Ir, Pt/10Rh, Pt/5Au, Pt-ZGS, Pt/5Au-ZGS, Pt/10Rh-ZGS
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28 Feb 1986; 22 p; Available from NTIS, PC A02/MF A01; 1 as DE87008160; Portions of this document are illegible in microfiche products.
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Toratani, H.; Kanamori, C.; Nakajima, S.; Nakagawa, K.; Izumitani, T.
Hoya Optics, Inc., Fremont, CA (USA)1983
Hoya Optics, Inc., Fremont, CA (USA)1983
AbstractAbstract
[en] The following experimental results are shown: (1) uniformity of AR coatings on Optosil and Sprasil provided by LLNL; (2) relation between cleaning methods and properties of AR coatings; (3) baking and sintering conditions of gel-derived films; (4) heat treatment of AR coating in O2 flow
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12 Sep 1983; 14 p; Available from NTIS, PC A02/MF A01; 1 as DE84011063
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