Abstract: This disclosure is directed to an optical element and method in which a UV-curable adhesive, used along the edge of the optic to keep it in a holder, has been stabilized against degradation by below 300 nm radiation. The technical solution to the degradation of the adhesive includes both 193 nm scatter light reduction and protective coatings of plasma modified AlF3 films on at least that part of the optical element that is in contact with the adhesive.

Abstract: The disclosure is directed to a photoelastic method for measuring the absolute zero crossover temperature Tzc of a sample of materials (transparent glass, glass-ceramic or ceramic) directly, without requiring calibration against a primary technique. The method involves subjecting the sample to a temperature gradient that generates a stress distribution pattern within the sample. When some portion of the sample is at a temperature equal to the Tzc of the material, the pattern adopts an easily identifiable shape whose measurement allows the calculation of Tzc. Silica-titania glass, which has a low thermal expansion, is used as an exemplary material.

Abstract: Methods of characterizing and measuring particulate accumulation in a family of particulate filters (10) are disclosed. The disclosure can be applied to diesel, gasoline and natural gas fueled engines, fluid streams bearing dust, and chemical and biological substances such as may be found in laboratory fluids, for example, air. In one embodiment, the disclosure is directed to measuring diesel particulate accumulation in a family of diesel particulate filters. The methods include measuring calibration complex terahertz transmission spectra (PC(f)) of at least a portion (17) of at least one particulate or diesel particulate filter in the family for different known particulate or diesel particulate amounts (ADP). The method also involves performing a partial least squares (PLS) analysis on the calibration complex terahertz transmission spectra to establish a calibration relationship between the complex terahertz transmission spectra and the particulate or diesel particulate amounts.

Abstract: In one aspect the invention is directed to a machinable glass-ceramic having a high degree of crystallinity (greater than 50 Vol. %), high mechanical strength (MOR>150 MPa) In accordance with the invention, the machinable glass-ceramics described herein consists essentially of, in weight percent, 35-55% SiO2, 6-18% Al2O3, 12-27% MgO, 3-12% F, 5-25% SrO, 0-20% BaO and 1-7% K2O. The machinable glass-ceramics of the invention have a dielectric constant of <8 (typically being in the range of 6-8) at 25° C. and 1 KHz; a loss tangent of <0.002 at 25° C. and 1 MHz; a CTE in the range of 80-120×10?7/° C. in the temperature range of 25-300° C.; a Poisson's ration of approximately 0.25; and a porosity of 0%.

Abstract: An imaging system for obtaining interferometric measurements from a sample spherical surface has a light source for providing an incident light beam, a beamsplitter disposed to direct the incident light beam toward the sample spherical surface and to direct a test light reflected from the sample spherical surface and a reference light reflected from a reference spherical surface toward an interferometric imaging apparatus. There is a lens assembly in the path of the incident light beam, with at least one lens element, wherein one of the at least one lens elements has an aspheric surface and wherein one of the at least one lens elements further provides the reference spherical surface facing the sample spherical surface. A reference plate is temporarily disposed in the path of the incident light beam for measuring the aspheric surface itself and is removable from the path of the incident light beam for obtaining interferometric measurements from the sample spherical surface.

Abstract: The invention is directed to a method and apparatus for joining together pieces of low thermal expansion glass to form parts that can be used in the manufacturing of mirror blanks. The parts are then used as a basis for the fabrication, using the method described herein, of hexagon sub-assemblies that would then be joined for assembly into mirror blanks.

Abstract: A method for forming shaped articles (28?) includes preparing a stack (26) having at least an adjacent set (27) of preformed material (28) and forming mold (30), where the preformed material (28) has an edge portion (34) that extends beyond a periphery of the forming mold (30), and the forming mold (30) has an external surface (32) with a desired surface profile of a shaped article. The stack (28) is heated. The stack (28) is advanced through a constriction (56) that has an internal surface configured to fold the edge portion (34) of the preformed material (28) into contact with the external surface (32) of the forming mold (30) as the edge portion (34) passes through the constriction (56), thereby forming a shaped article (28?) from the preformed material (28). The shaped article (28?) is then separated from the forming mold (30).

Abstract: A borosilicate glass composition suitable for manufacturing microreactor glass frits includes 12-22 mol % B2O3=12-22; 68-80 mol % SiO2; 3-8 mol % Al2O3, 1-8 mol % Li2O, and one of 0.5±0.1 mol % ZrO2 and 1.1±0.5 mol % F. After sintering a glass frit having the borosilicate glass composition, the glass frit has a surface crystalline layer of 30 ?m or less or is amorphous throughout.

Abstract: The invention is directed to calcium fluoride crystal optics with improved laser durability that can be used for the transmission of below 250 nanometer (nm) electromagnetic radiation. The optics consist of CaF2 as the major component and, in one embodiment, at least one dopant/amount selected >0.3-1200 ppm Mg, >0.3-200 ppm Sr, >0.3-200 ppm Ba, while Ce and Mn are <0.5 ppm. The doped crystal and optics made therefrom have a ratio of 515/380 nm transmission loss of less than 0.3 after exposure to greater than 2.8 MRads of ?-radiation.

Abstract: High-power excimer lasers are assembled with individually replaceable optical module subsystems containing consumable optical components. Windows formed in the enclosures of the optical modules incorporate a fluorescent material for converting ultraviolet light scattered from the components of the optical module into visible light emanating from the windows. Changes in the amount or location of the visible light emanating from the windows are interpreted as indications of the degradation in the performance of the optical modules.

Abstract: The invention is directed to a glass composition and articles made from the composition that are both polarizing and photorefractive. The glass has, for example, a composition consisting essentially of, in weight percent (“wt. %”) of 70-73 SiO2, 13-17% B2O3, 8-10% Na2O, 2-4% Al2O3, 0.005-0.1% CuO, <0.4% Cl, 0.1-0.5% Ag, 0.1-0.3% Br. In another embodiment the composition consists essentially of 70-77% SiO2, 13-18% B2O3, 8-10% Na2O, 2-4% Al2O3, 0.005-0.1% CuO, <0.4% Cl, 0.1-0.5% Ag, 0.1-0.3% Br. The glass can be used make articles or elements that can exhibits both the photorefractive effect and the polarizing effect within a single element or article, and can be used to make a variety of optical elements including Bragg gratings, filtering elements, and beam shaping elements and light collection elements for use in display, security, defense, metrology, imaging and communications applications.

Abstract: The disclosure is directed to a thin-film for use in below 300 nm laser systems that can be applied to a variety of substrate types. The thin film consists of a blocking layer of a selected material and a matching structure, the matching structure consisting of 1-7 layers of a selected material. The blocking layer serves to minimize or eliminate the transmission of below 300 nm laser light into an adhesive that is used to bond the substrate to a holder. The matching layer(s) minimize internal reflectance of below 300 nm laser light from the blocking layer back into the substrate.

Abstract: The invention is directed to optical elements that are coated with dense homogeneous fluoride films and to a method of making such coated elements. The coatings materials are a high (“H”) refractive index fluoride material and a low (“L”) refractive index material that are co-evaporated to form a coating layer of a L-H coating material (a co-deposited coating of L and H materials). Lanthanide metal fluorides (for example, neodymium, lanthanum, dysprosium, yttrium and gadolinium, and combinations thereof) are preferred metal fluorides for use as the high refractive index materials with lanthanum fluoride (LaF3) and gadolinium fluoride (GdF3) being particularly preferred. Aluminum fluoride (AlF3) and alkaline earth metal fluorides (fluorides of calcium, magnesium, barium and strontium) are the preferred low refractive index materials, with magnesium fluoride (MgF2) being a preferred alkaline earth metal fluoride.

Abstract: A transparent armor laminate system is described that utilizes a glass-ceramic material as the strike-face material, one or a plurality of intermediate layers, and a backing material. This laminate system offers improved performance with reduced weight over conventional all-glass or all-glass-ceramic transparent armor systems. The glass-ceramic material consists of a glass phase and a crystalline phase, the crystalline phase being selected from a group consisting of beta-quartz, mullite and combinations thereof.

Abstract: The invention is directed to highly reflective optical elements having an amorphous MgAl2O4?SiO2 coating with fluoride enhancements inserted and sealed by dense smooth SiO2 layers, and to a method for preparing such elements using energetic deposition techniques and the spinel crystalline form of MgAl2O4 as the source of the amorphous MgAl2O4 coating, The coating and the method described herein can be used to make highly reflective mirrors, and can also be applied to beamsplitters, prisms, lenses, output couplers and similar elements used in <200 nm laser systems.

Abstract: The present invention provides compositions and methods for producing porous ceramic articles. The compositions and methods comprise a ceramic precursor batch comprising an organic peroxide pore forming agent where the pore forming agent is an organo-adduct of hydrogen peroxide and an organic compound or an organic peroxide of the general formula R—O—O—R?. The organic peroxide pore forming agent is stable during extrusion and other methods for forming a green body and does not decompose until the green body is dried.

Abstract: In-line systems for and methods of measuring the moisture content of ceramic material within an extrusion system used to form ceramic articles are disclosed. One method includes arranging, relative to the extrusion system, at least one radio-frequency (RF) sensor system having an RF antenna, and generating through the RF antenna an RF field that resides substantially entirely within the ceramic material. The method also includes, in response to the RF field interacting with the ceramic material, generating in the RF sensor system a signal representative of a raw moisture-content measurement of the ceramic material. The method also includes generating calibration data by performing RF moisture-content measurements on samples of the ceramic material having different known moisture contents, and establishing a calibrated moisture-content measurement using the raw moisture-content signal and the calibration data. Both contact and non-contact systems and measurement methods are described.

Abstract: Methods are provided for testing a honeycomb body comprised of a core portion comprising honeycomb cell walls and a circumferential skin portion overlying at least some outer honeycomb cell walls. The circumferential skin portion includes a cement mixture layer. The method comprises the step of directing a fluid stream from a pressurized fluid source at the honeycomb body. The fluid stream is capable of separating at least part of the skin portion from the outer honeycomb cell walls when the adherence between at least part of the skin portion and the outer honeycomb cell walls is below a minimum threshold. In one example, the method further comprises the step of inspecting at least part of the interface between the honeycomb body and the skin portion during or after directing the fluid stream at the honeycomb body. In further examples, an apparatus is provided for testing the honeycomb body.

Abstract: A method for producing a fused silica glass containing titania includes synthesizing particles of silica and titania by delivering a mixture of a silica precursor and a titania precursor to a burner, growing a porous preform by successively depositing the particles on a deposition surface while rotating and translating the deposition surface relative to the burner, and consolidating the porous preform into a dense glass.

Abstract: The invention relates to opaque, colored glass-ceramic articles and to the production of opaque, colored glass-ceramic articles which can be readily formed to a desired shape using standard metal-working tools. The glass-ceramic material used to make such articles contains mica crystals as the predominant phase. The desired color is obtained through the addition of a colorant system to the precursor glass. In a particular embodiment the invention is directed to a black glass-ceramic article, the black color being obtained by the addition of iron oxides in levels as high as 20 wt %, which can yield a glass-ceramic having an iron-rice mica phase and/or a glass ceramic having an iron-rich mica phase plus an iron oxide phase.