Hoya Corporation

Hoya Glass Works, Ltd.

Hidemi Tajima

Takeshi Takahashi

Tadayuki Fujimoto

Tetsuro Izumitani

Shinichiro Hirota

Isao Masuda

Toshiharu Yamashita

Yoshihiko Matsuoka

Yukari Miyashita

Hiroyuki Sakai

Sho Amano

Yoshiyuki Asahara

Kishio Sugawara

Takayasu Mochizuki

Mitsuhisa Moriyama

In a press molding apparatus for press molding a plurality of glass materials into a plurality of glass optical elements by the use of a pressing mold including upper and lower molds each of which has a plurality of molding surfaces, at least one of the upper and the lower molds is a heat generator within which heat is generated when the heat generator is subjected to a high-frequency induction heating by an induction heating coil. The heat generator having a plurality of shape-processed portions () produced by partially processing a shape of the heat generator in order that a temperature distribution of the heat generator is adjusted. The apparatus simultaneously press forms, into the glass optical elements, the glass materials supplied between the molding surfaces of the upper and the lower molds which are subjected to the high-frequency induction heating.

Press molding apparatus

A press molding apparatus includes upper and lower mother moldsand. Each of the mother moldsandhas four molding surfaces arranged in a single line and satisfies the relationship given by L&#xd7;&#x3b1;&#xd7;&#x394;T/t&#x3c;0.0008, where L represents the length, t, the thickness, &#x3b1;, the thermal expansion coefficient, and &#x394;T, the temperature difference between both ends in the thickness direction during induction heating. The press molding apparatus may include a pressing mold set including upper mother moldsandattached to a common fixed shaftthrough upper supporting shaftsandand lower mother moldsanddriven by a common drive shaftthrough lower supporting shaftsand. The upper mother moldsandand the lower mother moldsandare collectively heated by induction heating coilsand, respectively.

Press molding apparatus and press molding method

A process for producing a polarizing glass containing shape-anisotropic metallic particles dispersed in an oriented state therein, which comprises drawing a glass preform containing metallic halide particles dispersed therein while its viscosity being held above 2&times;10,, but below 7&times;10,poises; and subjecting the drawn glass to a reducing treatment so that a part or all of the metallic halide particles are reduced to metallic particles, which process enables it to produce a polarizing glass with a high yield from a starting material of a glass containing metallic halide particles, while avoiding glass breakage or fracture during elongation as well as preventing the elongated metallic halide particles from returning to a spherical shape.

Process for the production of polarizing glass

Disclosed are a polarizing glass comprising a glass layer(s) which contains shape-anisotropic metallic particles dispersed therein in an oriented state and a base glass which causes substantially no light scattering, said glass layer being provided on a part or whole of at least one of faces of said base glass, which has polarizing properties comparable to conventional counterparts, a largely decreased transmission loss and a strength acceptable to practical use. Processes for the production of the polarizing glass are also disclosed.

Polarizing glass and production process thereof

A process for producing a polarizing glass containing shape-anisotropic metallic particles dispersed in an oriented state therein, which comprises drawing a glass preform containing metallic halide particles dispersed therein while its viscosity being held above 2.times.10.sup.6, but below 7.times.10.sup.7 poises; and subjecting the drawn glass to a reducing treatment so that a part or all of the metallic halide particles are reduced to metallic particles, which process enables it to produce a polarizing glass with a high yield from a starting material of a glass containing metallic halide particles, while avoiding glass to breakage or fracture during elongation as well as preventing the elongated metallic halide particles from returning to a spherical shape.

A composite slab laser medium provided with a non-doped layer containing substantially no laser active materials and a first and second doped layers provided at both sides of the non-doped layer, respectively, in such a manner to hold the non-doped layer, each of which contains a laser active material. In this composite slab laser, a first surface of the first doped layer and a second surface of the second doped layer are in contact with the outside of the composite slab laser medium and are parallel with each other. Further, a laser oscillation or an optical amplification is performed by extracting a laser beam which travels in a zig-zag path undergoing total internal reflection at the first and second surfaces employed as alternate reflecting surfaces within the composite slab laser medium. Moreover, layers made of laser glass containing Nd.sub.2 O.sub.3 of from 3 to 9% by weight is employed as the doped layers. Furthermore, a total of the thicknesses of the first and second doped layers is of from 0.6 to 8.0 mm. Additionally, the ratio of the total of the thicknesses of the first and second doped layers to the thickness of the whole composite slab laser medium is of from 0.075 to 0.40. Thereby, a composite slab laser medium, the gain of which is well balanced with the cross section of a laser beam, can be realized. Further, a laser provided with such a laser medium and a pump source for optical pumping of the laser medium can be provided. Thereby, a laser capable of emitting a laser beam with a high-beam-quality and high-peak-power can be realized.

Composite slab laser medium and a laser employing the composite slab

A laser medium for use in a composite slab type laser, wherein laser active layers are divided in the longitudinal direction of the laser medium by removing at least a part of a region, which is deviated from a zigzag path and a laser beam to be extracted therefrom does not pass through. Thereby amplified spontaneous emission can be weaken and parasitic oscillation can be effectively suppressed, and further laser oscillation and light amplification can be performed for a long period of time.

Laser medium for use in a composite slab type laser

A laser medium for use in a slab laser having a light absorbing member provided in a region, wich is deviated from a zigzag path to be followed by a laser beam to be extracted therefrom and thus the laser beam does not pass through. Thereby, parasitic oscillation can be effectively suppressed, and laser oscillation and light amplification can be performed for a long period of time.

Laser medium for use in a slab laser

A single mode laser glass fiber showing excellent laser oscillation characteristics even at a short fiber length can be efficiently obtained using a phosphate laser glass with excellent laser characteristics.

Single mode phosphate laser glass fiber

A Faraday rotation single-mode fiber having a high Verdet constant is disclosed, the core and the cladding of the fiber being made of a glass having the following composition: 26 to 38 mol % SiO.sub.2, 18 to 34 mol % B.sub.2 O.sub.3, 17 to 26 mol % Al.sub.2 O.sub.3, 18 to 32 mol % Tb.sub.2 O.sub.3, 0 to 5 mol % ZrO.sub.2, 0 to 5 mol % Ce.sub.2 O.sub.3, 0 to 5 mol % Pr.sub.2 O.sub.3, 0 to 5 mol % Dy.sub.2 O.sub.3 and 0 to 5 mol % Ho.sub.2 O.sub.3, provided that the total amount of the above ingredients is not less than 97 mol % and the total amount of Ce.sub.2 O.sub.3, Pr.sub.2 O.sub.3, Dy.sub.2 O.sub.3 and Ho.sub.2 O.sub.3 is 0 to 5 mol %.

Faraday rotation single-mode optical fiber

An optical glass comprising, in % by weight

Optical glass

An optical glass comprising, in % by weight,

Glass for use as an element of a Faraday rotator, consisting essentially of, by mol%, 10-30 Tb.sub.2 O.sub.3, 10-30 Al.sub.2 O.sub.3, and 30-80 SiO.sub.2 + B.sub.2 O.sub.3, with the proviso that SiO.sub.2 .gtoreq.15 and B.sub.2 O.sub.3 .gtoreq.10, and as optional components 0-5 ZrO.sub.2, 0-1 Sb.sub.2 O.sub.3, 0-1 As.sub.2 O.sub.3, and 0-2 AlF.sub.3. The glass has a large Verdet constant and a reduced absorption of light in the visible and infrared wavelength regions.

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Hamura, Japan

Hidemi Tajima