Corning Incorporated

William Rogers Rosch

Kenneth Edward Hrdina

Carlos Alberto Duran

Sezhian Annamalai

Michael Lucien Genier

Horst Schreiber

Robert Stephen Pavlik, Jr

Michael William Price

Keith J Donohue

Jeffrey L Sunderland

James R Cole

Charlene Marie Smith

Steven Bruce Dawes

Paul Maynard Schermerhorn

Bryan Ray Wheaton

Qiao Li

John Edward Maxon

Colleen Renee Clar

Annealing treatments for modified titania-silica glasses and the glasses produced by the annealing treatments. The annealing treatments include an isothermal hold that facilitates equalization of non-uniformities in fictive temperature caused by non-uniformities in modifier concentration in the glasses. The annealing treatments may also include heating the glass to a higher temperature following the isothermal hold and holding the glass at that temperature for several hours. Glasses produced by the annealing treatments exhibit high spatial uniformity of CTE, CTE slope, and fictive temperature, including in the presence of a spatially non-uniform concentration of modifier.

Ultralow expansion titania-silica glass

A doped silica-titania ('DST') glass article that includes a glass article having a glass composition comprising a silica-titania base glass containing titania at 7 to 14 wt. % and a balance of silica, and a dopant selected from the group consisting of (a) F at 0.7 to 1.5 wt. %, (b) BOat 1.5 to 5 wt. %, (c) OH at 1000 to 3000 ppm, and (d) BOat 0.5 to 2.5 wt. % and OH at 100 to 1400 ppm. The glass article has an expansivity slope of less than about 1.3 ppb/Kat 20&#xb0; C. For DST glass articles doped with F or BO, the OH level can be held to less than 10 ppm, or less than 100 ppm, respectively. In many aspects, the DST glass articles are substantially free of titania in crystalline form.

Doped ultra-low expansion glass and methods for annealing the same

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 consists of CaFas the major component and Mg in an amount in the range of 13 ppm to 20 ppm while Ce and Mn are &#x3c;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 &#x3b3;-radiation. Further, the doped crystal and optics made therefrom exhibit a greatly improved lifetime as shown by ALDT testing to at least 1 billion pulses.

Calcium fluoride optics with improved laser durability

A method of loading at least one fused silica article with hydrogen. At least one fused silica article is first loaded with an amount of hydrogen so that the hydrogen concentration at the center of the article exceeds a minimum concentration upon completion of loading. An amount of hydrogen is the removed from the fused silica article so that the fused silica article has an average hydrogen concentration that is less than the maximum average concentration limit. The surface region of the fused silica article is then reloaded to ensure that the hydrogen concentration throughout the article is within a predetermined pressure range. A fused silica article comprising hydrogen is also described.

Three pressure hydrogen loading cycle for fused silica

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 CaFas the major component and, in one embodiment, at least one dopant/amount selected &#x3e;0.3-1200 ppm Mg, &#x3e;0.3-200 ppm Sr, &#x3e;0.3-200 ppm Ba, while Ce and Mn are &#x3c;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 &#x3b3;-radiation.

A laser beam is generated and transmitted within an enclosed pathway through at least one crystal optic at a power density that progressively degrades transmissivity of the crystal optic with accumulating fluence. The crystal optics are cooled below normal operating temperatures to slow the progressive degradation in the transmissivity of the crystal optics with the accumulating fluence or to accommodate a higher power density without correspondingly increasing the progressive degradation in transmissivity.

Active cooling of crystal optics for increased laser lifetime

A crystal optical material is illuminated at a wavelength of light that does not ionize the crystal optical material. Birefringence is measured between a plurality of voxels within the crystal optical material having spatial dimensions small enough to distinguish optical propagations of the light encountering boundary regions between subgrains of the crystal mosaic from optical propagations of the light through the subgrains themselves. The measured birefringence is evaluated for quantifying a characteristic of the crystal matrix. Metrics describing the crystal matrix are associated with performance of the crystal optical material.

Mosaic quantification by birefringence measurement

The invention is directed to method of preparing metal fluoride single crystals and particularly to crystals where the metal is calcium, barium, magnesium or strontium, or a mixture thereof. The invention uses a decreasing fast cooling profile and an increasing slow cooling profile for the hot zone and the cold zone, respectively, after crystal formation during cooling from melt temperatures to a first temperature. A substantially constant cooling rate is then applied to the both zones during cooling from the first temperature to a final temperature, usually room temperature. It has been found that the substantially constant cooling rate during the annealing process results in crystals having improved homogeneity and birefringence.

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Corning, NY, United States of America

William Rogers Rosch