Abstract: An optical imaging system is provided that includes a rod lens array and has the optimum refractive index distribution for achieving a high resolving power. The refractive index distribution of rod lenses can be expressed by n(r)2=n02·{1?(g·r)2+h4·(g·r)4+h619 (g·r)6+h8·(g·r)8}Eq. 45 where r is a radial distance from the optical axis of the rod lenses, n0 is a refractive index on the optical axis of the rod lenses, and g, h4, h6 and h8 are refractive index distribution coefficients. The refractive index distribution coefficients h4, h6 and h8 are set on a spheroid in a Cartesian coordinate system with h4 being x-axis, h6 being y-axis and h8 being z-axis. The spheroid is defined by a vector X* that is expressed by X*=(x, y, z)=O*+kAA*+kBB*+kCC*Eq.

Abstract: The wavefront aberrator of the present invention includes a pair of transparent windows, or plates, separated by a layer of monomers and polymerization initiator, including a broad class of epoxies. This monomer exhibits a variable index of refraction across the layer, resulting from controlling the extent of its curing. Curing of the epoxy may be made by exposure to light, such as ultraviolet light. The exposure to light may be varied across the surface of the epoxy to create a particular and unique refractive index profile.

Abstract: A collimator for use at multiple wavelengths includes an optical fiber and a gradient index lens positioned at a constant distance with respect to an end of the optical fiber. The gradient index lens has a chromatic aberration at a selected pitch less than 0.01 over a selected range of the infrared spectral region.

Abstract: An aligning tool having a plurality of grooves formed side by side is provided; gradient index rod lenses are placed in alignment within the grooves at an average spacing of 1 ?m-5 ?m; the gradient index rod lenses are fixed to form an integral unit as they maintain the aligned state; thereafter the end faces of each rod lens are polished.

Abstract: Two lenses are used for forming a collimator parallel pair, in which the distance between the two lenses is substantially made coincident with the maximum distance allowing beam waists to be formed at equal distances from the two lenses respectively.

Abstract: A micro prismatic structure is formed inside the light transmission face of a gradient-index lens, in which the projections have a height of at least 0.25 ? and the distance between the neighboring projections is at most ?, based on the applied wavelength ?. Preferably, the micro prismatic structure has conical projection units that are aligned in the light transmission face of the lens in a mode of hexagonal, tetragonal or orthorhombic arrangement. The conical projections may be in any form of circular cones, polygonal cones, flat-headed circular cones (circular cones of which the apex has been cut horizontally) or flat-headed polygonal cones .

Abstract: A lens for optical scanning condenses luminous flux deflected by an optical deflector to a plane to be scanned in a scanning image forming optical system. The lens is made of a plastic material by molding. A reference axis of an N-th order approximating curve of refractive index distribution ?n(x) of the lens is away from a center of a passing area, through which the luminous flux passes in the lens, by equal to or more than 10% of the width of the passing area.

Abstract: An optical scanning lens used in a multi-beam scanning optical apparatus including a first mechanism reforming the light beams into line images, a deflecting mechanism reforming the light beams into multiple scanning beams, and a second mechanism reforming the multiple scanning beams into scanning light spots running on a recording surface. The optical scanning lens has a refractive index profile and is included in the second optical mechanism, and satisfies a formula (m?1)×PLs×V/WLs?2.3×10?6, where m is a number of light emission points, PLs is a pitch of the multiple beams, V represents the refractive index profile, W [mm] represents an effective recording width of the recording surface, and WLs represents an effective range of the optical scanning lens in the sub-scanning direction corresponding to the effective recording width W. An optical scanning apparatus or image forming apparatus may use the optical scanning apparatus.

Abstract: An imaging system includes a pulsed laser, a pre-compensator for chromatic dispersion, a transmission optical fiber, and a GRIN lens. The pre-compensator chirps optical pulses received from the laser. The transmission optical fiber transports the chirped optical pulses from the pre-compensator. The GRIN lens receives the transported optical pulses from the transmission optical fiber. The GRIN lens has a wider optical core than the transmission optical fiber and substantially narrows the transported optical pulses received from the transmission optical fiber.

Abstract: An optical system for optical communications is composed of a transparent material having a refractive index distribution formed by changing the molar ratio of metal oxide with valence of 2 or more. The metal oxide with valence of 2 or more includes, for example, Fe2O3. Using such an optical system for optical communications, optical communication components such as an optical fiber collimator and an optical isolator are composed.

Abstract: The planar lens of the invention having a flat glass substrate, in which a refractive index distribution is formed by diffusing a refractive index-increasing component into the flat glass substrate in a substantially hemispherical form or semicylinder form, wherein the refractive index-increasing component is silver, and the flat glass substrate comprises Li as an alkali metal that is subject to an ion exchange with the silver.

Abstract: An aligning tool having a plurality of grooves formed side by side is provided; gradient index rod lenses are placed in alignment within the grooves at an average spacing of 1 &mgr;m-5 &mgr;m; the gradient index rod lenses are fixed to form an integral unit as they maintain the aligned state; thereafter the end faces of each rod lens are polished.

Abstract: The present invention provides a plastic lens, used in an optical system of an optical image recording apparatus, which is low in birefringence, and is less susceptible to displacement of focus caused by resistance to environment. At least a part of a non-effective area is concave, and there is a sink mark in the concave portion. The shape of the concave portion is determined so as to achieve a GI ratio (&Dgr;f/f0)≦5%.

Abstract: In an image pickup device, a single refractive index distribution lens having a refractive index distribution which is substantially proportional to the square of the distance from an optical axis in a cross-section vertical to the optical axis is provided as an imaging lens in the neighborhood of the imaging face of an image pickup element. Specifically, the positional relationship between the image pickup element and the lens is fixed by adhesion of organic solvent or the like. Further, an infrared-ray cut filter is formed on the light incident face of the refractive index distribution lens.

Abstract: A fiber collimator is provided, comprising at least two optical components, one of the optical components (e.g., an optical element such as a collimating lens or a plano-plano pellet) having a surface that has a comparatively larger cross-sectional area than the surface of the other optical component(s) (e.g., at least one optical fiber). The optical components are joined together by fusion-splicing, using a laser. A gradient in the index of refraction is provided in at least that portion of the surface of the optical element to which the optical fiber(s) is fusion-spliced or at the tip of the optical fiber. The gradient is either formed prior to or during the fusion-splicing. Back-reflection is minimized, pointing accuracy is improved, and power handling ability is increased.

Abstract: A light source-optical fiber coupler using a gradient index rod lens 12 by which a diffused luminous flux emitted from a light source (for example, a semiconductor laser 10) is coupled onto an end surface of an optical fiber (for example, a single-mode optical fiber 14). The gradient index rod lens has a planar end surface facing the light source, and a convex spherical end surface facing the optical fiber. The gradient index rod lens has a light source side numerical aperture NA2 in a range of from 0.40 to 0.75, an effective lens radius r0 in a range of from 0.3 to 1.0 mm, and a spherical curvature radius R1 in a range of from 1.2 to 2.0 mm.

Abstract: A compositional range for a mother glass composition for graded index lenses which has a desired refractive index and is less apt to be devitrified and to develop cracks upon ion exchange was obtained by incorporating at least a given amount of one or more ingredients which are selected from oxides of metal elements ranging from yttrium, atomic number 39, to tantalum, atomic number 73, and which are less apt to cause glass coloration into a glass based on SiO2—TiO2—Li2O—Na2O and containing no lead oxide. In particular, a compositional range in which a large angular aperture is obtained and devitrification is less apt to occur was obtained by incorporating Ta2O5 and ZrO2 in a specific proportion and in specific amounts.

Abstract: A fiber collimator is provided, comprising at least two optical components, one of the optical components (e.g., an optical element such as a collimating lens or a plano—plano pellet) having a surface that has a comparatively larger cross-sectional area than the surface of the other optical component(s) (e.g., at least one optical fiber). The optical components are joined together by fusion-splicing, using a laser. A gradient in the index of refraction is provided in at least that portion of the surface of the optical element to which the optical fiber(s) is fusion-spliced or at the tip of the optical fiber. The gradient is either formed prior to or during the fusion-splicing. Back-reflection is minimized, pointing accuracy is improved, and power handling ability is increased.

Abstract: Photosensitive optical materials are used for establishing more versatile approaches for optical device formation. In some embodiments, unpatterned light is used to shift the index-of-refraction of planar optical structures to shift the index-of-refraction of the photosensitive material to a desired value. This approach can be effective to produce cladding material with a selected index-of-refraction. In additional embodiments gradients in index-of-refraction are formed using, photosensitive materials. In further embodiments, the photosensitive materials are patterned within the planar optical structure. Irradiation of the photosensitive material can selectively shift the index-of-refraction of the patterned photosensitive material. By patterning the light used to irradiate the patterned photosensitive material, different optical devices can be selectively activated within the optical structure.

Abstract: A miniaturized lens array for unity magnification imaging comprises a plurality of rod lenses arranged in one row. An arrangement pitch D of the rod lenses is defined to satisfy (2 m+1)·D≦2.1 mm or 2.5 mm. An angle of aperture &thgr; of the rod lens is defined to satisfy &agr;D/6×{n·cos−1(−&agr;/2/m)+(4 m2/&agr;2−1)1/2}≦&thgr;≦&agr;D/2×(4/m2/&agr;2−1)1/2. The arrangement pitch D and angle of aperture &thgr; are defined in this manner, and it is therefore possible to obtain the lens array whose difference between a total width and effective lens width is equal to or smaller than 2.1 mm or 2.5 mm.

Abstract: A collimator array includes a plurality of collimators. Each collimator includes a lens and an optical fiber optically coupled to the lens. The lens is arranged so that its optical axis is parallel to one another. In each collimator, a core axis of the optical fiber is positioned relative to the optical axis of the lens so that an optical beam is emitted from a predetermined position at a predetermined angle.

Abstract: Graded index lenses, methods, and devices are disclosed. In certain embodiments, he lenses are made from generally cylindrical glass members having a radially varying refractive index and have a pitch less than about 0.23. Other embodiments relate to graded index lenses having a pitch between about 0.23 and 0.25 and an index gradient less than or equal to 0.3.

Abstract: A method of producing a collimator or collimator array is constituted by the steps of: fixing long-size gradient index rod lens raw materials on a substrate having end surfaces each forming a plane so that the long-size gradient index rod lens raw materials are arranged side by side at intervals of the predetermined pitch while optical axes of the gradient index rod lens raw materials are parallel to one of the end surfaces of the substrate; cutting the substrate provided with the gradient index rod lens raw materials at a predetermined position in a plane perpendicular to the optical axes of the gradient index rod lens raw materials to thereby divide the substrate provided with the gradient index rod lens raw materials into lens array parts; adjusting the divided lens array parts so that each of the gradient index rod lens raw materials in the lens array parts has a defined lens length; and arranging the lens array parts so that the cut end surfaces of the lens array parts are made to face each other while o

Abstract: Methods and apparatus for producing fused silica members having high internal transmission are disclosed. The apparatus and methods are capable of producing fused silica having internal transmission of at least 99.65%/cm at 193 nm.

Abstract: A micro prismatic structure is formed inside the light transmission face of a gradient-index lens, in which the projections have a height of at least 0.25 &lgr; and the distance between the neighboring projections is at most &lgr;, based on the applied wavelength &lgr;. Preferably, the micro prismatic structure has conical projection units that are aligned in the light transmission face of the lens in a mode of hexagonal, tetragonal or orthorhombic arrangement. The conical projections may be in any form of circular cones, polygonal cones, flat-headed circular cones (circular cones of which the apex has been cut horizontally) or flat-headed polygonal cones .

Abstract: A rod lens for an optical communication module is not easily damaged. An input side end surface of the rod lens has an inclined surface. The inclined surface is inclined by a predetermined angle with respect to a central axis of the rod lens to reduce the reflection loss. A flat contact surface, which is perpendicular to the central axis, is formed on the distal end of the rod lens. By simply arranging two of the rod lenses to contact each other, the rod lenses are optically coupled in the optimum manner without being damaged.

Abstract: A device is proposed to symmetrize the radiation from one or from several linear optical emitters. The device possesses per emitter 1, 1a, 1b a cylindrical lens optical unit 2, 2a, 2b with one or more cylindrical lenses, which collimate each light beam in the y-direction, where by rotating at least one of the cylindrical lenses around the z-axis or by providing a discontinuous diffracting element, each light beam is diffracted at a different diffraction angle in the y-direction. The device additionally contains a director-collimator optical unit 3, which collimates each light beam in the x-direction and diffracts at different diffraction angles so that the main beams of the individual light beams in the x-direction converge at a specified distance from the emitter and run parallel in the y-direction. Finally, the device has a redirecting optical unit 4 which compensates for the diffraction of the light beam in the x-direction caused by the director-collimator optical unit 3.

Abstract: An optical element can effectively correct misalignment of focused positions of optical spots and an optical spot pitch deviation with respect to image heights due to a refractive index distribution therein. The optical element includes a lens, which serves as an optical system in an optical scanner, is shaped in such a profile that misalignment of a focused position of the optical spot due to the refractive index distribution is corrected for image heights.

Abstract: An optical microscope includes a compound GRIN objective and a lens system. The compound GRIN objective is able to form an image of an object located near one end of the GRIN objective. The compound GRIN objective is configured to limit a lateral field of view for the image to a distance equal to the diameter of the GRIN objective. The lens system is positioned to form a magnified image of an image formed by the compound GRIN objective.

Abstract: An optical interconnect system having a GRIN rod lens, the GRIN rod lens having a first end and a second end, and further having a preselected length, a preselected width and a preselected index of refraction. Means are fixedly secured to the first end of the GRIN rod lens for emitting electromagnetic radiation and means are fixedly secured to said second end of said GRIN rod lens for receiving the emitted electromagnetic radiation. The GRIN rod lens forms an image of the emitting means onto the receiving means and overcomes problems associated with misalignment.

Abstract: An aligning tool having a plurality of grooves formed side by side is provided; gradient index rod lenses are placed in alignment within the grooves at an average spacing of 1 &mgr;m-5 &mgr;m; the gradient index rod lenses are fixed to form an integral unit as they maintain the aligned state; thereafter the end faces of each rod lens are polished.

Abstract: An acoustic lens having two or more regions, each region having a different acoustic index of refraction. The lens may have a simple, non-compound, surface in which both regions form different sections of the same convex or concave curve with the same functional dependence. The transition between the two regions may be gradual or abrupt. The attenuation and other characteristics of the lens may be tailored to provide apodisation and to filter out unwanted frequencies.

Abstract: The planar lens of the invention having a flat glass substrate, in which a refractive index distribution is formed by diffusing a refractive index-increasing component into the flat glass substrate in a substantially hemispherical form or semicylinder form, wherein the refractive index-increasing component is silver, and the flat glass substrate comprises Li as an alkali metal that is subject to an ion exchange with the silver.

Abstract: A graded optical element is provided that includes graded layers of optical material, wherein the layers may or may not have different indexes of refraction. A method for making such a graded thickness optical element is also provided. A masking layer is preferably spaced above a substrate, where the masking layer has at least one aperture therein. Optical material is then deposited on the substrate through the aperture in the masking layer to form a layer of refr material that extends laterally beyond the aperture in the masking layer in at least one region.

Abstract: An optical microscope includes a compound GRIN objective and a lens system. The compound GRIN objective is able to form an image of an object located near one end of the GRIN objective. The compound GRIN objective is configured to limit a lateral field of view for the image to a distance equal to the diameter of the GRIN objective. The lens system is positioned to form a magnified image of an image formed by the compound GRIN objective.

Abstract: A miniaturized lens array for unity magnification imaging comprises a plurality of rod lenses arranged in one row. An arrangement pitch D of the rod lenses is defined to satisfy (2m+1)·D≦2.1 mm or 2.5 mm. An angle of aperture &thgr; of the rod lens is defined to satisfy &agr;D/6×{n·cos−1(−&agr;/2/m)+(4m2/&agr;2−1)½}≦&thgr;≦&agr;D/2×(4m2/&agr;2−1)½. The arrangement pitch D and angle of aperture &thgr; are defined in this manner, and it is therefore possible to obtain the lens array whose difference between a total width and effective lens width is equal to or smaller than 2.1 mm or 2.5 mm.

Abstract: A collimating device (20) comprises a GRIN lens (22), a filter (24) and an outer tube (26). The GRIN lens and the filter are both secured in the outer tube. The outer tube is made of stainless steel, and has a first receiving portion (261) and a second receiving portion (262). The first receiving portion is cylindrical, and defines a cylindrical cavity (264) therein for receiving the GRIN lens. The second receiving portion is also cylindrical, and defines a generally rectangular cavity (266) therein for receiving the filter. The GRIN lens and the filter are glued in the outer tube with relatively little epoxy, and with no excess epoxy contaminating optical faces thereof.

Abstract: An aspherical rod lens converts light emitted from a predetermined light source or an emittance end of an optical fiber into predetermined light, the aspherical rod lens has

Abstract: The invention relates to a focusing device comprising a Luneberg lens comprising a homogeneous volume of dielectric. It is characterized in that the dielectric comprises a granular agglomerate defined by a homogeneous granule size distribution of thermoplastic granules, at least one plurality of these granules being welded together by granule boundaries in order to keep said volume consolidated. Particular application to lenses for the tracking of nongeostationary satellites, of at least one geostationary satellite, or for use in an MMDS system.

Abstract: A graded optical element is provided that includes graded layers of optical material, wherein the layers may or may not have different indexes of refraction. A method for making such a graded thickness optical element is also provided. A masking layer is preferably spaced above a substrate, where the masking layer has at least one aperture therein. Optical material is then deposited on the substrate through the aperture in the masking layer to form a layer of refr material that extends laterally beyond the aperture in the masking layer in at least one region.

Abstract: A GRIN fiber lens has a silica-glass core whose refractive index has a radial profile. The profile has a radial second derivative whose average magnitude in the core is less than about 1.7×10−6 microns−2 times the value of the refractive index on the axis of the GRIN fiber lens.

Abstract: An optical scanning lens used in a scanning and imaging optical system in which a beam deflected by a light deflector is condensed on or in the vicinity of a surface to be scanned. The optical scanning lens is formed through plastic mold, and a distribution of the refractive indexes &Dgr;n(x) inside of the optical scanning lens has a local maximum within a range through which the beam passes through the lens.

Abstract: An optical element has a small reflection loss of light on a boundary surface between a photonic crystal and the normal medium. The optical element includes: a normal medium region having a first refractive index; a photonic crystal region having a refractive index which is changed periodically depending upon a position thereof, the photonic crystal region having as an averaged refractive index a second refractive index different from the first refractive index; and an intermediate region interposed between the normal medium region and the photonic crystal region, the intermediate region having a refractive index which is gradually changed from the first refractive index to the second refractive index.

Abstract: The present invention relates to an optical device capable of homogenizing luminous energy and homogenizing polarized light simultaneously, and an optical illumination system of a projector having decreased volume by using the optical device for homogenizing luminous energy and polarized light.

Abstract: An apparatus includes an optical element, a GRIN lens, and a detector. The optical element has a first optical aperture. The GRIN lens has first and second ends. The first end of the GRIN lens is positioned to receive light from the first optical aperture. The detector is configured to measure values of a characteristic of light emitted from the first end in response to multi-photon absorption events in a sample illuminated by light from the second end of the endoscopic probe.

Abstract: An imaging optical element is comprised of a gradient index rod lens 12 of which external peripheral surface is a smooth surface without being processed by means of a flare-cut treatment and a field limitation stop member 14 mounted on the lens surface at the incidence side thereof. As for the stop member, the length t thereof is: t>1o·D/2X (where, 1o: a lens working distance, D: a rod lens diameter, X: a radius of field of view), whereby the angle of incidence of beam &thgr; at the center of the lens satisfies &thgr;<tan−1(X/1o) . It is effective especially when an application thereof is made to a rod lens array comprised of a plurality of rod lenses arranged into an array.

Abstract: A graded index lens is obtained by treating a raw glass material having a rod shape by ion exchange using silver to form a refractive index distribution in the radial direction of the rod, wherein the raw glass material comprises a glass composition of the following components: 15<Na2O≦30 mol %; 10<Al2O3≦25 mol %; 27.5≦SiO2≦55 mol %; 3≦B2O3≦18 mol %; 2.5≦MgO≦18 mol %; 0≦Ta2O5≦5 mol %; 0≦La2O3≦3 mol %; 0≦BaO≦3 mol %; and 0≦ZrO2≦3 mol %.

Abstract: A rod lens array having a structure in which a large number of rod lens elements are combined into one unit while the large number of rod lens elements are arrayed in a plurality of rows.

Abstract: It is known to couple a collimated beam of light into the end of an optical fibre with a graded index lens having an angled facet at the lens/fibre interface to reduce the amplitude of Fresnel retroreflected power. The expense incurred in providing angled facets is avoided by using a two-part compound lens. One part is a graded index lens part having an axial length shorter than a quarter period. To this is bonded a cylindrical uniform refractive index lens part whose index is matched with the effective refractive index of the fibre. This reduces the amplitude of the retroreflection power by causing the displacement of the Fresnel reflection from the lens focus.

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.