Abstract: A lens function-including optical lens according to the present invention is constituted by: at least one step-index optical fiber; and at least one gradient index optical fiber having an outer diameter equal to that of the step-index optical fiber and having a periodic length exhibiting a lens function, the gradient index optical fiber being joined or attached to an end surface of the step-index optical fiber. The present invention is especially effective in a single mode optical fiber which is typical of the step-index optical fiber. The gradient index optical fiber can be produced by an ion exchange method.

Abstract: In a laser processing method for accurately forming a convexo-concave structure on the surface of a glass substrate, a periodic optical intensity distribution of a laser beam is obtained by an interference between diffracted light beams of +1 degree and −1 degree emitted from a phase mask, onto which the laser beam is irradiated, in the vicinity of the emission side of the phase mask, and a glass substrate, on which a thin film is formed, is set in the area where the periodic optical intensity distribution is provided. As a result, the thin film is evaporated or ablated depending on the periodic optical intensity, thereby a diffraction grating, which has the same period as that of the varying optical intensity, is formed on the glass substrate.

Abstract: In a laser processing method for accurately forming a convexo-concave structure on the surface of a glass substrate, a periodic optical intensity distribution of a laser beam is obtained by an interference between diffracted light beams of +1 degree and −1 degree emitted from a phase mask, onto which the laser beam is irradiated, in the vicinity of the emission side of the phase mask, and a glass substrate, on which a thin film is formed, is set in the area where the periodic optical intensity distribution is provided. As a result, the thin film is evaporated or ablated depending on the periodic optical intensity, thereby a diffraction grating, which has the same period as that of the varying optical intensity, is formed on the glass substrate.

Abstract: The present invention relates to a method of preparing porous metal powder, a starting metal being oxidized and then reduced followed by that the obtained block metal body is milled. According to the present invention, the starting metal is oxidized in the presence of chlorine and/or chloride. The present block metal body after reduction has prismatic particles complicatedly entangled like a root so that the pore of the metal powder is open.

Abstract: An optical element comprises a solid material in an optical path of the optical element, wherein the solid material comprises a first material and a second material, and the first and second materials have first and second temperature coefficients of refractive index, respectively, wherein the first temperature coefficient of refractive index has a sign which is opposite that of the second temperature coefficient of refractive index.

Abstract: Titanium is added in the form of atoms, a colloid, or ions to a glass to be subjected to laser processing in which the ablation or vaporization caused by the energy of an absorbed laser light is utilized. Since titanium can be incorporated into the glass through melting, the threshold value for processing can be easily regulated by changing the amount titanium to be added and a material having evenness in processability can be obtained.

Abstract: A mother glass for producing a glass adapted for laser processing utilizing abrasion or evaporation by absorbed laser energy, includes: a silicate glass as a main component; and aluminum and at least one alkali metal in substantially the same molar amount.

Abstract: The invention provides an optical device using two- or three-dimensional photonic crystal having a repeatedly periodic structure in two or three different directions. The photonic crystal in this optical device is processed into a prism structure or a blazed diffraction grating structure.

Abstract: An SiO2-TiO2-Li2O-Na2O-based glass composition containing no lead oxide having incorporated therein specific amounts of specific components which are selected from oxides of the metal elements having an atomic number of 30 (Y) to 73 (Ta) and which hardly cause coloration of glass. The glass composition has a desirable refractive index, hardly undergoes devitrification, and hardly develops cracks on ion exchanging and is suitable as glass for a graded index lens.

Abstract: A laser processing method for removing glass by melting, evaporation or ablation from sheet-like glass substrate for forming microscopic concavities and convexities. Diffraction grating and planar microlens array obtained thereby.

Abstract: In an optical device using an end surface of a periodic multilayer structure as a beam incidence surface or a beam exit surface, a high-resolving-power spectroscopic apparatus can be achieved without increase in size of the apparatus and by use of good directivity of beam leaked from the periodic multilayer structure and strong wavelength dependence of the angle of the leaked beam. Particularly, by disposing layer surfaces of the multilayer structure perpendicularly to a substrate, optical devices suitable for integration of the devices can be formed.

Abstract: A wavelength monitoring apparatus according to the present invention constituted by: an optical device made of a periodic multilayer structure; a beam source optically connected to at least one end surface of the multilayer structure, the one end surface being not parallel to layer surfaces of the mutilayer structure; and a beam detecting means provided for detecting beam made to exit from at least one surface of the multilayer structure at a specific angle with respect to a specific wavelength, the one surface being parallel to the layer surfaces of the mutilayer structure.

Abstract: In the present invention, a surface 7 of a glass substrate 1 is irradiated with a laser beam 2 to thereby form a V-shaped groove 6. At that time, the laser beam 2 is condensed outside and above the glass substrate 1. The distance between a beam-condensing point 4 of the laser beam 2 and the surface 7 of the glass substrate 1 is changed to thereby make it possible to change the angle between opposite side surfaces of the V-shaped groove. The angle is in a range of from 30 degrees to 120 degrees. Further, the laser beam used in the present invention is pulsed light, preferably with a pulse width not larger than 10 picoseconds.

Abstract: A rain sensor including light emitting means 7 for guiding light into a window glass so as to undergo total internal reflection within the window glass, light receiving means 8 for receiving the light which has undergone total internal reflection within the window glass, and means for detecting the amount of water drops adhered to or present upon the window glass so as to output a driving signal to a wiper driver apparatus 20, a difference signal corresponding to a difference between a preset reference value and an output signal of an amplifier circuit 17 of the light receiving means is fed back to the amplifier 17, and an amplification factor of the amplifier circuit 17 is adjusted so as to maintain the output signal thereof at a constant value irrespective of the operation condition of the wiper, when electrical power is applied to the rain sensor 2.

Abstract: In a laser processing method for accurately forming a convexo-concave structure on the surface of a glass substrate, a periodic optical intensity distribution of a laser beam is obtained by an interference between diffracted light beams of +1 degree and −1 degree emitted from a phase mask, onto which the laser beam is irradiated, in the vicinity of the emission side of the phase mask, and a glass substrate, on which a thin film is formed, is set in the area where the periodic optical intensity distribution is provided. As a result, the thin film is evaporated or ablated depending on the periodic optical intensity, thereby a diffraction grating, which has the same period as that of the varying optical intensity, is formed on the glass substrate.

Abstract: An optical demultiplexer has a plurality of transparent or translucent tubes combined in axially slidably interfitting relationship to each other. An input optical fiber, a collimator lens, and a diffraction grating are mounted on the tubes, preferably on end faces of the tubes. The optical demultiplexer can be assembled for centered alignment by installing the input optical fiber, the collimator lens, and the diffraction grating on the tubes, and sliding the tubes relatively to each other according to passive alignment.

Abstract: An optical device in which an end surface of a periodic multilayer structure is provided as a beam incidence surface or as a beam exit surface. The optical device can realize a high resolving-power spectroscopic apparatus without having any increase in size of the apparatus and by use of good directivity of beam leaked from the multilayer structure and strong wavelength dependence of an angle of the leaked beam.

Abstract: A laser processing method for removing glass by melting, evaporation or ablation from sheet-like glass substrate for forming microscopic concavities and convexities. Diffraction grating and planar microlens array obtained thereby.

Abstract: The invention relates to a flame-retardant thermoplastic resin composition having incorporated therein a trace of stabilized red phosphorus, which achieves both improvement of heat resistance and flame retardation without using chlorine nor bromine and also possesses long-term heat stability and smells little. The composition comprises (A) 50 to 95 parts by weight of a polycarbonate resin and (B) 5 to 50 parts by weight of a thermoplastic polyester resin, contains (C) 0.1 to 5 parts by weight, per 100 parts by weight of the total amount of (A) and (B), of coated stabilized red phosphorus and preferably contains (D) 0.1 to 100 parts by weight, per 100 parts by weight of the total amount of (A) and (B), of a silicate compound.

Abstract: A laser processing method for removing glass by melting, evaporation or ablation from sheet-like glass substrate for forming microscopic concavities and convexities. Diffraction grating and planar microlens array obtained thereby.