Synthetic quartz glass substrates are prepared by furnishing a synthetic quartz glass block, coating two opposed surfaces of the glass block with a liquid having a transmittance of at least 99.0%/mm at a birefringence measuring wavelength, measuring a birefringence of the glass block by directing light thereacross, determining a slice thickness on the basis of the birefringence measurement and the dimensions of the substrate, and slicing the glass block at the determined slice thickness.

An article including a glass having that includes SiO.sub.2, Al.sub.2O.sub.3, and B.sub.2O.sub.3 and least one of Li.sub.2O, Na.sub.2O, K.sub.2O, MgO, CaO, SrO, BaO, SnO.sub.2, ZnO, La.sub.2O.sub.3, F, and Fe.sub.2O.sub.3, wherein the glass includes a dielectric constant of about 10 or less and/or a loss tangent of about 0.01 or less, both as measured with signals at 10 GHz.

A fiber sensor includes an optical fiber configured for operation at a wavelength from about 800 nm to about 1600 nm. The optical fiber includes a cladding that is defined by a fiber outer diameter and a core that is surrounded by the cladding. The core of the optical fiber has a Rayleigh scattering coefficient, .sub.s, that is controlled by controlling a concentration of one or more dopants in the core. The Rayleigh scattering coefficient is tuned to be within a predetermined range of an optimum Rayleigh scattering coefficient for a given total length, L, of the optical fiber. The predetermined range is from about 70% of the optimum .sub.s to about 130% of the optimum .sub.s.

A resin composition for inorganic molded article production use, which is provided with inorganic particles each containing amorphous SiO.sub.2 and a photocurable resin composition, in which the photocurable resin composition contains a photocurable resin precursor and a photopolymerization initiator, the content of the inorganic particles is 60% by mass or more with respect to the total amount of the photocurable resin composition and the inorganic particles and is 60% by mass or more with respect to the entire amount of the resin composition for inorganic molded article production use, and the viscosity of the composition for inorganic molded article production use is 10000 mPa.Math.s or less.

One aspect relates to a process for the preparation of a quartz glass body including: i.) providing a silicon dioxide granulate, ii.) making a first glass melt out of the silicon dioxide granulate, iii.) making a glass product out of at least one part of the glass melt, iv.) reducing the size of the glass product to obtain a quartz glass grain, v.) making a further glass melt from the quartz glass grain and vi.) making a quartz glass body out of at least one part of the further glass melt. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to a reactor, which is obtainable by further processing of the quartz glass body.

The present invention pertains to: a method for manufacturing an ultraviolet-resistant quartz glass, said method including melting a synthetic silica powder; and a method for manufacturing an ultraviolet-resistant quartz glass, said method including performing arc plasma melting of a silica powder. Provided is an ultraviolet-resistant quartz glass having an ultraviolet-resistance of 2500 seconds, wherein, taking the initial transmittance during irradiation of a quadruple higher harmonic (266 nm) of a YAG laser (irradiation performed at a YAG laser output of 180 mW, pulse width of 20 nsec, and frequency of 80 kHz) at an optical path length of 30 mm to be 100%, the irradiation period until the transmittance falls to 3% is defined as resistance to ultraviolet rays (referred to as ultraviolet-resistance). Also provided is an optical member for YAG-laser higher harmonics, said optical member comprising this quartz glass.

Described is a process for the refinement of a quartz powder, comprising the step of separating microparticles of refractory minerals, in particular minerals containing rare earth metal compounds, from the quartz powder by an elutriation step.

Systems and methods for forming a permanent plug in a subterranean formation include providing a solution of colloidal silica and pumping the colloidal silica into a bore of a subterranean well so that the colloidal silica penetrates pores of the subterranean formation. The colloidal silica within the pores of the subterranean formation is dehydrated to form a glass-like material within the pores of the subterranean formation.

Systems and methods for forming a permanent plug in a subterranean formation include providing a solution of colloidal silica and pumping the colloidal silica into a bore of a subterranean well so that the colloidal silica penetrates pores of the subterranean formation. The colloidal silica within the pores of the subterranean formation is dehydrated to form a glass-like material within the pores of the subterranean formation.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50 C., preferably 50 C.<T.sub.h<250 C.