According to various embodiments described herein, an article comprises a glass or glass-ceramic substrate having a first major surface and a second major surface opposite the first major surface, and a via extending through the substrate from the first major surface to the second major surface over an axial length in an axial direction. The article further comprises a helium hermetic adhesion layer disposed on the interior surface; and a metal connector disposed within the via, wherein the metal connector is adhered to the helium hermetic adhesion layer. The metal connector coats the interior surface of the via along the axial length of the via to define a first cavity from the first major surface to a first cavity length, the metal connector comprising a coating thickness of less than 12 μm at the first major surface. Additionally, the metal connector coats the interior surface of the via along the axial length of the via to define a second cavity from the second major surface to a second cavity length, the metal connector comprising a coating thickness of less than 12 μm at the second major surface and fully fills the via between the first cavity and the second cavity.

According to various embodiments described herein, an article comprises a glass or glass-ceramic substrate having a first major surface and a second major surface opposite the first major surface, and a via extending through the substrate from the first major surface to the second major surface over an axial length in an axial direction. The article further comprises a helium hermetic adhesion layer disposed on the interior surface; and a metal connector disposed within the via, wherein the metal connector is adhered to the helium hermetic adhesion layer. The metal connector coats the interior surface of the via along the axial length of the via to define a first cavity from the first major surface to a first cavity length, the metal connector comprising a coating thickness of less than 12 μm at the first major surface. Additionally, the metal connector coats the interior surface of the via along the axial length of the via to define a second cavity from the second major surface to a second cavity length, the metal connector comprising a coating thickness of less than 12 μm at the second major surface and fully fills the via between the first cavity and the second cavity.

Preparation of halogen-doped silica is described. The preparation includes doping silica with high halogen concentration and sintering halogen-doped silica to a closed-pore state in a gas-phase environment that has a low partial pressure of impermeable gases. Impermeable gases are difficult to remove from halogen-doped fiber preforms and lead to defects in optical fibers drawn from the preforms. A low partial pressure of impermeable gases in the sintering environment leads to a low concentration of impermeable gases and a low density of gas-phase voids in densified halogen-doped silica. Preforms with fewer defects result.

Preparation of halogen-doped silica is described. The preparation includes doping silica with high halogen concentration and sintering halogen-doped silica to a closed-pore state in a gas-phase environment that has a low partial pressure of impermeable gases. Impermeable gases are difficult to remove from halogen-doped fiber preforms and lead to defects in optical fibers drawn from the preforms. A low partial pressure of impermeable gases in the sintering environment leads to a low concentration of impermeable gases and a low density of gas-phase voids in densified halogen-doped silica. Preforms with fewer defects result.

A mask blank glass substrate having a maximum value of a circularly averaged power spectral density of 1,000 nm.sup.4 or less at a spatial frequency of 0.1 μm.sup.−1 or more and 20 μm.sup.−1 or less, the maximum value being obtained by measuring a surface morphology of a region of 10 μm×10 μm with an atomic force microscope.

A method for preparing a microstructure on the surface of glass by titanium oxide nanoparticle-assisted infrared nanosecond laser, including the following steps: (1) dropwise applying a titanium oxide nanoparticle hydrogel onto the surface of a glass sample; (2) pressing another piece of glass on the surface of the hydrogel, so the hydrogel is evenly distributed between the two pieces of glass, and allowing the two pieces of glass to stand horizontally for a period of time to air-dry the hydrogel; (3) separating the two pieces of glass to obtain a glass with a uniform titanium oxide nanoparticle coating; (4) forming a microstructure using an infrared nanosecond laser with a wavelength of 1064 nm; and (5) performing after-treatment, including ultrasonically cleaning the sample with acetone, absolute ethanol and deionized water respectively for 10 min to remove titanium oxide nanoparticles attached to the surface, to obtain a glass sample with the microstructure.

Provided is a titanium-containing quartz glass having excellent UV absorption. The quartz glass absorbs ultraviolet rays having a wavelength of 250 nm or less, ozone generation-related adverse effects on the human body, are prevented, a decrease in transmittance of the quartz glass in the range from near-ultraviolet to visible light due to being colored when irradiated with ultraviolet rays does not occur, absorption build-up or lamp burst-inducing deformation build-up, which is caused by a structural change in the quartz glass that occurs in the range of 200-300 nm when irradiated with ultraviolet rays, is suppressed, and a decrease in transmittance at intended wavelength ranges does not occur even when exposed to ultraviolet rays. The titanium-containing quartz glass having excellent UV absorption is colorless, wherein the average concentration of titanium is 10-500 ppm, the concentration of OH group is 10-350 ppm.

Provided is a titanium-containing quartz glass having excellent UV absorption. The quartz glass absorbs ultraviolet rays having a wavelength of 250 nm or less, ozone generation-related adverse effects on the human body, are prevented, a decrease in transmittance of the quartz glass in the range from near-ultraviolet to visible light due to being colored when irradiated with ultraviolet rays does not occur, absorption build-up or lamp burst-inducing deformation build-up, which is caused by a structural change in the quartz glass that occurs in the range of 200-300 nm when irradiated with ultraviolet rays, is suppressed, and a decrease in transmittance at intended wavelength ranges does not occur even when exposed to ultraviolet rays. The titanium-containing quartz glass having excellent UV absorption is colorless, wherein the average concentration of titanium is 10-500 ppm, the concentration of OH group is 10-350 ppm.

An optical fiber according to an embodiment includes a core and a cladding. The average value n1_ave of the refractive index of the core, the minimum value nc_min of the refractive index of the cladding, and the refractive index n0 of pure silica glass satisfy relationships of n1_ave>nc_min and nc_min<n0. The cladding contains fluorine. The fluorine concentration in the cladding is adjusted to be minimum in the outermost portion of the cladding including the outer peripheral surface of the cladding.

Described is a method of producing synthetic fused silica in which the synthetic flame used in the method has a ratio of the Full Width at Half Maximum (FWHM.sub.vert) vertical luminous intensity to the Full Width at Half Maximum (FWHM.sub.hori) horizontal luminous intensity greater than 10 in a targetless state, the luminous intensities being measured in candela/mm.sup.2.