Abstract: The present invention relates to a 215- to 222-nm wavelength laser light generating device comprising: an excitation light source part for converting a laser light with a wavelength of 1030 to 1064 nm to a second harmonic, and generating a laser light with a wavelength of 515 to 532 nm; an optical parametric oscillating part for generating a signal light with a wavelength of 858 to 887 nm and an idler light with a wavelength of 1288 to 1330 nm using the laser light with the wavelength of 515 to 532 nm as an excitation light; a separating part for separating the signal light and the idler light; a first wavelength converting part for generating a fourth harmonic from the signal light; a second wavelength converting part for generating a deep ultraviolet light with a wavelength of 215 to 222 nm by sum frequency with a second harmonic of the excitation light from the idler light; and a coupling part for coupling the fourth harmonic from the first wavelength converting part and the deep ultraviolet light from the

Abstract: The present invention relates to a 399.08-nm wavelength ultraviolet laser light generating device, comprising: an excitation light source part for converting a 1064.2-nm laser light to a second harmonic, and generating a 532.1-nm laser light; an optical parametric oscillating part for generating a 798.15-nm signal light and a 1596.3-nm idler light using the 532.1-nm laser light; a first wavelength converting part for generating a 399.08-nm light by sum frequency generation of the 1596.3 nm idler light and a 532.1-nm light; and a second wavelength converting part for generating a 399.08-nm light of a second harmonic from the 798.15-nm signal light. The order of the first wavelength converting part and the second wavelength converting part is random. The present invention relates to a 228.04-nm wavelength ultraviolet laser light generating device comprising the 399.08-nm wavelength laser light generating device and a third wavelength converting part for subjecting a 399.08-nm light and a 532.

Abstract: 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.

Abstract: Fused silica glass having an internal transmittance of UV with 245 nm wavelength, being at least 95% at 10 mm thickness, a OH content of not larger than 5 ppm, and a content of Li, Na, K, Mg, Ca and Cu each being smaller than 0.1 ppm. Preferably the glass has a viscosity coefficient at 1215° C. of at least 1011.5 Pa·s; and a Cu ion diffusion coefficient of not larger than 1×10?10 cm2/sec in a depth range of greater than 20 ?m up to 100 ?m, from the surface, when leaving to stand at 1050° C. in air for 24 hours. The glass is made by cristobalitizing powdery silica raw material; then, fusing the cristobalitized silica material in a non-reducing atmosphere. The glass exhibits a high transmittance of ultraviolet, visible and infrared rays, has high purity and heat resistance, and exhibits a reduced diffusion rate of metal impurities, therefore, it is suitable for various optical goods, semiconductor-production apparatus members, and liquid crystal display production apparatus members.

Abstract: Fused silica glass having an internal transmittance of UV with 245 nm wavelength, being at least 95% at 10 mm thickness, a OH content of not larger than 5 ppm, and a content of Li, Na, K, Mg, Ca and Cu each being smaller than 0.1 ppm. Preferably the glass has a viscosity coefficient at 1215° C. of at least 1011.5 Pa·s; and a Cu ion diffusion coefficient of not larger than 1×10?10 cm2/sec in a depth range of greater than 20 ?m up to 100 ?m, from the surface, when leaving to stand at 1050° C. in air for 24 hours. The glass is made by crystobalitizing powdery silica raw material; then, fusing the crystobalitized silica material in a non-reducing atmosphere. The glass exhibits a high transmittance of ultraviolet, visible and infrared rays, has high purity and heat resistance, and exhibits a reduced diffusion rate of metal impurities, therefore, it is suitable for various optical goods, semiconductor-production apparatus members, and liquid crystal display production apparatus members.

Abstract: A cathode of sufficiently low hydrogen overvoltage is provided which is useful in electrolysis of water or of an aqueous alkali metal chloride solution such as a sodium chloride solution. A process for producing the cathode is also provided. The low hydrogen overvoltage cathode has an electroconductive base material coated with an alloy layer containing nickel and molybdenum, the alloy layer containing the nickel at a content ranging from 35 to 90% by weight and the molybdenum at a content ranging from 10 to 65% by weight. The alloy laser has an X-ray diffraction (CuK.alpha. line) pattern with a main peak at an angle ranging from 42 to 45.degree. with a peak half width ranging from 0.4 to 7.degree.. One process for producing the low hydrogen overvoltage cathode of the present invention involves plating an electroconductive base material by an arc discharge type ion plating method.