A reforming mandrel and a method of use reforming mandrel to reform glass are described. The reforming mandrel comprises an upstream portion, a downstream portion and an at least partially hollow interior. The upstream portion may have an intake inlet for fluid flow. The downstream portion may be axially spaced from the upstream portion. The downstream portion may have a flattened cross-section defined by flattened peripheral portions joined by curved peripheral portions. At least one curved peripheral portion may be made of porous material resistant to a temperature of at least 1000 C. The at least partially hollow interior may communicate with the intake inlet and the porous material.

A method for producing a component includes joining individual wall parts, especially for producing a melting crucible for use at a high operating temperature in a crucible-pulling method for quartz glass, wherein at least two wall parts of a refractory metal or of a base alloy of a refractory metal are provided, butt-joined to form a joint and joined together by sintering at a temperature above 1500 C. to form the component. A sealant is inserted into the joint to provide a component of improved tightness and to ensure improved sintering of the individual parts of the component. A component produced according to the method, particularly a melting crucible, particularly in a crucible pulling method for quartz glass, has the joint between the butt-joined walls closed in a gas-tight manner by a sealant.

A method for producing a component includes joining individual wall parts, especially for producing a melting crucible for use at a high operating temperature in a crucible-pulling method for quartz glass, wherein at least two wall parts of a refractory metal or of a base alloy of a refractory metal are provided, butt-joined to form a joint and joined together by sintering at a temperature above 1500 C. to form the component. A sealant is inserted into the joint to provide a component of improved tightness and to ensure improved sintering of the individual parts of the component. A component produced according to the method, particularly a melting crucible, particularly in a crucible pulling method for quartz glass, has the joint between the butt-joined walls closed in a gas-tight manner by a sealant.

An illumination system for medical therapeutic and/or diagnostic system is provided. The illumination system includes a laser light source and a light guide. The light guide has a proximal end that is connectable and/or assignable to the one laser light source. The light guide has a distal end with a diffuser element having a radial, spherical emission characteristic. The diffuser element includes a diffuser main body made of an inorganic material, in particular a glass, a glass ceramic, a glass-like substance or a composite substance of the aforementioned substances. The diffuser main body has a scattering element and has a surface that is pore-free and smooth.

An illumination system for medical therapeutic and/or diagnostic system is provided. The illumination system includes a laser light source and a light guide. The light guide has a proximal end that is connectable and/or assignable to the one laser light source. The light guide has a distal end with a diffuser element having a radial, spherical emission characteristic. The diffuser element includes a diffuser main body made of an inorganic material, in particular a glass, a glass ceramic, a glass-like substance or a composite substance of the aforementioned substances. The diffuser main body has a scattering element and has a surface that is pore-free and smooth.

A method of fabricating one or more glass cells includes drawing one or more glass capillaries from a source of glass material. The method includes performing a first conditioning of one or more inner surfaces of the one or more capillaries. The method includes sealing one or more first ends of the one or more capillaries using thermal energy. The method includes performing a second conditioning of the one or more inner surfaces after the sealing. The method includes purifying the one or more capillaries to increase a purity of a gas used to fill the one or more capillaries. The method includes filling the one or more capillaries using the gas after the purifying. The method includes pressurizing the one or more capillaries to a given pressure. The method includes sealing one or more second ends of the one or more capillaries using thermal energy.

A method of fabricating one or more glass cells includes drawing one or more glass capillaries from a source of glass material. The method includes performing a first conditioning of one or more inner surfaces of the one or more capillaries. The method includes sealing one or more first ends of the one or more capillaries using thermal energy. The method includes performing a second conditioning of the one or more inner surfaces after the sealing. The method includes purifying the one or more capillaries to increase a purity of a gas used to fill the one or more capillaries. The method includes filling the one or more capillaries using the gas after the purifying. The method includes pressurizing the one or more capillaries to a given pressure. The method includes sealing one or more second ends of the one or more capillaries using thermal energy.

A method includes heating a hollow-core preform comprising an outer tube and an inner tube. The outer tube includes an inner radius r.sub.ocp and an outer radius R.sub.ocp. The inner tube includes an inner radius r.sub.cp and an outer radius R.sub.cp. The method further includes drawing a hollow-core optical fiber from the hollow-core preform at a draw tension T.sub.g in grams, thereby elongating the outer tube into an outer cladding of the hollow-core optical fiber and the inner tube to a capillary of the hollow-core optical fiber. The draw tension T.sub.g and/or a differential capillary pressure p.sub.c are selected at least in part based on a non-dimensional parameter

[00001]$X_1=\frac{3\left(R_{\mathrm{ocp}}^2-r_{\mathrm{ocp}}^2\right)R_{\mathrm{cp}}\left(p_c{r}_{\mathrm{cp}}-2{}_c\right)}{4{\mathrm{Tr}}_{\mathrm{cp}}\left(R_{\mathrm{cp}}-r_{\mathrm{cp}}\right)},$

where T is the draw tension in dynes and T=981T.sub.g, p.sub.c is in dynes/cm.sup.2, .sub.c in dyne/cm is a surface energy of a glass material forming the inner tube, and 0.5X.sub.10.75.

A method includes heating a hollow-core preform comprising an outer tube and an inner tube. The outer tube includes an inner radius r.sub.ocp and an outer radius R.sub.ocp. The inner tube includes an inner radius r.sub.cp and an outer radius R.sub.cp. The method further includes drawing a hollow-core optical fiber from the hollow-core preform at a draw tension T.sub.g in grams, thereby elongating the outer tube into an outer cladding of the hollow-core optical fiber and the inner tube to a capillary of the hollow-core optical fiber. The draw tension T.sub.g and/or a differential capillary pressure p.sub.c are selected at least in part based on a non-dimensional parameter

[00001]$X_1=\frac{3\left(R_{\mathrm{ocp}}^2-r_{\mathrm{ocp}}^2\right)R_{\mathrm{cp}}\left(p_c{r}_{\mathrm{cp}}-2{}_c\right)}{4{\mathrm{Tr}}_{\mathrm{cp}}\left(R_{\mathrm{cp}}-r_{\mathrm{cp}}\right)},$

where T is the draw tension in dynes and T=981T.sub.g, p.sub.c is in dynes/cm.sup.2, .sub.c in dyne/cm is a surface energy of a glass material forming the inner tube, and 0.5X.sub.10.75.

A method may include: feeding a hollow-core preform into a draw furnace at a preform feed rate V.sub.p; heating the hollow-core preform comprising an outer tube having an inner radius/diameter r.sub.p/ID.sub.preform and an outer radius/diameter R.sub.p/OD.sub.preform; and drawing a hollow-core optical fiber from the hollow-core preform at a fiber draw rate V.sub.f and a draw tension , thereby elongating the outer tube of the hollow-core preform to an outer cladding of the hollow-core optical fiber having an inner radius/diameter r.sub.f/ID.sub.fiber and an outer radius/diameter R.sub.f/OD.sub.fiber; wherein: the interior cavity of the outer tube is under a differential core pressure P.sub.core, the differential core pressure P.sub.core, the inner and outer radii r.sub.p and R.sub.p of the outer tube are selected such that a tight control over target inner and outer radii r.sub.f and R.sub.f and a fiber dimension sensitivity ID.sub.fiber of the outer cladding can be achieved.