Abstract: A double blazed binary diffractive optical element beam splitter having alternating and opposing individual blazed diffraction gratings upon a multilevel surface relief phase grating structure for splitting an incident monochromatic light beam into a first and second diffracted light beams. The double blazed binary diffractive optical element and two single blazed binary diffractive optical elements can form either a beam splitting apparatus or a beam combining apparatus. Double blazed binary diffractive optical elements and sets of two single blazed binary diffractive optical elements can form beam splitting and combining apparatuses to produce a single beam or two closely spaced beams.

Abstract: A displacement detection apparatus comprises a light source 1, a first diffraction grating including a blazed grating for diffracting and splitting light from the light source to irradiate a 0-order diffraction light and a +1-order diffraction light to a second diffraction grating, a third diffraction grating including a blazed grating for combining a +1-order reflected diffraction light produced by the reflection and diffraction of the 0-order diffraction light by the second diffraction grating and a -1-order reflected diffraction light produced by the diffraction of the +1-order diffraction light by the second diffraction grating to produce an interference light, and a photo-sensing element for converting the interference light to a signal representing a change in the second diffraction grating.

Abstract: A color image reading apparatus comprises a plurality of line sensors which are a plurality of one-dimensional sensor arrays disposed on a single substrate, a projection optical system for projecting an image of a subject on the sensors, a blazed diffraction grating disposed in an optical path between the projection optical system and the sensors to separate light from the subject into a plurality of color lights, and a wavelength selection device disposed in an optical path between the subject and the sensors to permit only a beam of light within a specific wavelength range to pass therethrough.

Abstract: A complex lens of one-piece construction has first and second lens surfaces opposite to each other. At least one of the first and second lens surfaces of the complex lens is integrally formed with a diffraction grating. This diffraction grating has a multiplicity of substantially parallel grating grooves each being of a generally triangular, sinusoidal or trapezoidal cross-section. An optical head utilizing the complex lens is also disclosed.

Abstract: In a color image pickup apparatus having an objective lens or a member for removably mounting the objective lens, an image pickup device for converting the image of an object formed by the objective lens into a color electrical signal, and an optical low-pass filter comprising a diffraction grating and disposed between the rear end of the objective lens and the image pickup device, the optical low-pass filter satisfies the condition.0.7f.sub.C .ltoreq.1/d.ltoreq.f.sub.Y -0.7f.sub.C,where d is the pitch of the diffraction grating, f.sub.Y is the spatial frequency for making the luminance signal of the image pickup means into a specimen, and f.sub.C is the spatial frequency for making the color signal of the image pickup means into a specimen.

Abstract: Chromatic dispersion between first and second wavelengths of light is corrected by a lens/zone plate combination. The zone plate is adapted both to send most of the first wavelength light into its zeroth order and to send most of the second wavelength light into its first order and to change the focal length of the second wavelength light to coincide with the focal length of the first wavelength light. A preferred embodiment includes a zinc/selinide sulfide lens having a zone plate etched onto one of its surfaces. The zone plate has a multi-step phase profile including four phase levels. The lens/zone plate combination is particularly adapted for use with CO.sub.2 and HeNe lasers to bring their focal lengths into coincidence.

Abstract: Optical reproducing apparatus utilizes a dual diffraction grating having first and second diffraction gratings with the diffraction gratings oriented at an angle with respect to one another to polarize an incident return beam into TM and TE components. TM and TE components emerge from the dual diffraction grating at a slight angle with respect to one another and are focused on a photodetector chip by an objective lens. In accordance with a first specific embodiment of the apparatus, the TM and TE polarized components are focused directly on a photoelectric chip, with the TE component focused on a spot size focus detector comprised of three rectangular photoelectric elements. One photoelectric element is disposed between the other two with a pair of parallel interfaces. Disturbances introduced into the TE beam are in the direction of the parallel interfaces, rendering the spot size focus detector wavelength-insensitive.

Abstract: An optical pickup apparatus in which light from a light source is led to an information medium and reflected light from the information medium is led to a hologram to be incident as a +1st order diffraction beam on a photodetector to obtain information signals. The hologram has a stair-like cross-sectional configuration, and a ratio of the width of a step of the stair-like cross-sectional configuration relative to a grating pitch of the hologram is arranged to vary in accordance with a position within a surface of the hologram.

Abstract: An image reading apparatus is provided with a light-receiving device, an imaging optical system and a blazed diffraction grating. In the light-receiving device, a plurality of line sensors are arranged on the same substrate. An image of an object to be imaged is formed on the light-receiving device by the imaging optical system. The blazed diffraction grating is arranged in an optical path between the imaging optical system and the light-receiving device. The blazed diffraction grating color-separates a light beam from the object to be imaged into a plurality of light components. The diffraction grating is so constructed to have grating lines with at least two different grating heights.

Abstract: A diffractive/refractive hybrid lens for use in an optical data storage system as an objective is provided by a convex-plano singlet having a refractive element defined by plano-convex surfaces and a diffractive element defined by a Fresnel zone-like pattern on the plano surface which together provide the total power of the lens. The refractive lens is made of a high index, high dispersion glass so that the curvature and thickness of the refractive lens is minimized while providing a large numerical aperture (at least 0.45) at the expense of increased longitudinal chromatic aberration, which are compensated by the diffractive element and without the need for one or more additional curved surfaces as in low index biaspheric glass objective lenses for chromatic and mono-chromatic aberration reduction, which increases the thickness and curvatures of the lens.

Abstract: An optical disk head which includes a substrate, a light path for allowing light beam to propagate in a zigzag form, having a thickness and width of 10 times greater than the wavelength, a light source optically connected to the light path so as to allow an incident light from the light source to propagate therethrough, a first light condenser optically connected to the light path so as to radiate the light beam propagated through the light path upon an object provided toward a top surface of the substrate, a second light condenser for guiding the light beam reflected from the object into the light path, and an optical detector for detecting the light beam propagated through the light path guided by the second light condenser.

Abstract: The present invention involves a corrective optical lens construction and process for its manufacture. The lens construction consists of a glass lens having a corrective layer consisting of a blazed grating of annuli whose angles are formed to correct aberrations in the glass lens. In a first embodiment, the corrective layer is formed on one convex surface of the lens. In a second embodiment, the corrective layer is formed on a second convex surface of the lens. Embodiments also describe alternative lens shapes and corrective layer construction. A method of manufacturing the lens is also disclosed in which the resin corrective layer is molded to the glass lens.

Abstract: A phase grating optical low-pass filter having wavelength selectivity consisting of a plurality of layers which are the same in refractive index at a certain wavelength and different from one another in refractive index dispersion, and has a configuration for generating a phase difference at a boundary of the layers.

Abstract: A process is provided for fabricating multi-discrete-phase binary Fresnel acoustic and optical lenses through the use of standard microelectronic fabrication techniques, thereby enabling such lenses to be produced repeatedly and economically to exacting design specifications.

Abstract: A reticle and a method of fabricating the samer for projecting a fine pattern on an object surface comprises: a. transparent substrate; a first type phase-shifter selectively patterned and deposited on the substrate producing a phase difference between the light passing therethrough and the light passing through the other areas without phase-shifter; and a second type phase-shifter selectively patterned and forming a groove in the substrate producing a phase difference between the light passing therethrough and the light passing through the other areas without phase-shifter. The reticle may include a patterned shield layer which interrupts transmission of light, and the phase difference of the first and second type phase-shifters is many times selected substantially equal to a half wavelength of light. Another type of a reticle comprises: a transparent substrate; a phase-shifter of a first groove; and another phase-shifter of a second deeper groove formed in the first groove.

Abstract: A beam shaping system for an astigmatic light source utilizes two lenses, both having diffractive power. A first lens shapes the beam in a first dimension and a second lens shapes the beam in a second dimension perpendicular to the first.

Abstract: A lens according to the invention has diffractive power and two primary foci, where one focus is associated with the first diffractive order and one with the second diffractive order.

Abstract: An image reader comprises a monolithic 3-line sensor having three one-dimension sensor arrays such as solid-state imaging devices arranged on one substrate with each array being spaced by a predetermined distance along a direction perpendicular to the array direction, a focusing optical system for focusing an image of an object onto the sensor, and a one-dimension blazed diffraction grating arranged in a light path between the focusing optical system and the sensor, closer to the sensor than to an exit pupil of the focusing optical system for spectroscopically separating a light from one point on the object by a diffraction effect to color-decompose it into three colors perpendicularly to the array and directing the color-decomposed lights to the corresponding sensor arrays. Distances from a center sensor array of the 3-line sensor to two other sensor lines are different from each other.

Abstract: A color reading apparatus includes a reflection type one dimensional blazed diffraction grating for color separation which is provided on an optical path between an imaging optical system for focusing a color image on a photosensor, and the photosensor in which three line sensors are disposed on a common substrate. The pitch of the diffraction grating varies in a direction of the pitch so as to control the reflective diffraction angle from reflection points resulting from different incident angles on the diffraction grating and to prevent the occurrence of a blur of .+-.1st-order diffracted light in the pitch cross section on the diffraction grating.

Abstract: A beam-slicer (6) for generating a plurality of radiation beams, or pencil beams (7), from incident radiation (3). Each of the beams is directed to a different region of space. The beam-slicer includes a substrate (17) that, for a transmission grating embodiment, is comprised of a material that is substantially transparent to incident radiation having wavelengths of interest. The substrate includes a plurality of regions, or sub-apertures (8), formed within a surface thereof, each of the regions defining a blazed transmission or reflection grating for deviating incident radiation into a radiation beam. The blazed diffraction grating is formed such that the wavelengths of interest within each radiation beam are simultaneously deviated at a same, predetermined angle. Also disclosed is a Sample Point Interferometer that includes the beam-slicer. The beam-slicer generates pencil beams, each of which is directed to a retroreflector (9) positioned upon a surface of a structure (10) under measurement.

Abstract: A monochromator of the Czerny-Turner type includes an entrance slit, a collimating mirror for receiving light output by the entrance slit, a planar grating for receiving light reflected by the collimating mirror, a focusing mirror for receiving light reflected by the grating, and an exit slit for receiving light focused by the focusing mirror. Light generally proceeds from the entrance slit to the collimating mirror, form the collimating mirror to the grating, from the grating to the focusing mirror and from the focusing mirror to the exit slit. The improvement comprises the use of a single toroidal collimating mirror in the system in combination with a spherical focusing mirror.

Abstract: A color image reading apparatus comprises a plurality of line sensors, an optical system for forming an image of a subject, a blazed diffraction grating inserted in light path between the optical system and the sensors, and a slit inserted in light path between the subject and the optical system. The blazed diffraction grating separates light beams from the subject into plurality color lights and directs them to their corresponding sensor arrays. The slit has an aperture, the size of which in the array direction of the sensors is longer than that in the direction perpendicular to the array direction of the sensors. By construction of the apparatus according to the present invention, noise light can be prevented so as to read high accuracy digital color image.

Abstract: An image reading apparatus including a diffraction grating element including a transparent plate shaped in the form of consecutive steps to separate a light reflected from a document into a zero order light, -1 order light, and +1 order light. The transparent plate is arranged so that the zero order light has a wavelength in a blue region and +1 order light and -1 order light have wavelengths either in green and red regions, respectively or in red and green regions, respectively.

Abstract: A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4.multidot.10.sup.-5 inch and a profile width of at least 10.sup.-3 inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight.

Abstract: A fresnel lens in which each of the facets is so dimensioned and configured that the distance between the facet and a focal point of the lens is (n+k) .lambda. where n is an integer, .lambda. is the wavelength of the radiation passing through the lens, and k is a fraction between 0 and 1 which is substantially constant for any facet over the entire face of the lens. Preferably the lens comprises a plurality of zones, each comprising a number of facets, the integer n being constant for each facet of each said zone, but being different for facets of different zones.

Abstract: A bifocal lens of the Cohen lens design utilizing phase zone plate optics and a facet depth of one-half wavelength of the design wavelength, where the primary focal points are at two orders, specifically the 0.sup.th and 1.sup.st orders, and the brightness at each primary focal point is equal at about 0.40.

Abstract: Enhanced energy transfers are achieved between optical beams by operating at wavelengths in the near-bandgap region of a photorefractive material, and employing an electrorefractive effect previously proposed only for single beams. An electric field is applied across a photorefractive medium of sufficient intensity to induce an electrorefractive coupling and consequent energy transfer between the beams. Gain enhancements are possible by orienting the photorefractive medium to obtain an electro-optic as well as an electrorefractive effect, and by a moving grating technique. The direction of energy transfer between the beams is controlled by the electric field direction, and can be reversed by reversing the field. Operation in the infrared region is made possible with semi-insulating materials. Applications include optical switches, amplifiers and phase conjugators.

Abstract: An ophthalmic lens exhibiting diffractive power has a plurality of diffractive zones and smooth surfaces. The zones are arranged such that R.sub.0.sup.2 does not equal R.sub.1.sup.2 -R.sub.0.sup.2 where R.sub.0 is the radius of the central zone and R.sub.1 is the radius of the first annular zone.

Abstract: An optical device suitably employable in intraocular and contact lenses that employs a phase zone plate of a Cohen lens design that relies on a small number of zones to provide multifocal images.

Abstract: A bifocal lens of the Cohen lens design utilizing phase zone plate optics and a facet depth of one-half wavelength of the design wavelength, where the primary focal points are at two orders, specifically the 0.sup.th and 1.sup.st orders, and the brightness at each primary focal point is equal at about 0.40.

Abstract: A multifocal optical device is provided for focusing light traveling parallel to an optical axis of the device. The multifocal optical device comprises a multifocal phase zone plate including at least two annular zones disposed substantially concentrically about the optical axis and spaced in a radial dimension from the optical axis in proportion to the square root of q, where q is an integer zone number; and an absorbing material disposed on a portion of ones of the annular zones for absorbing a portion of the light.

Abstract: A multifocal ophthalmic lens has diffractive power produced by a plurality of concentric zones. The zones have radii that meet the conditionR.sub.0.sup.2 is not equal to R.sub.1.sup.2 -R.sub.0.sup.2where R.sub.0 is the radius of the central zone and R.sub.1 is the radius of the first annular zone.

Abstract: A phase diffraction grating apparatus which is usable to generate an array of N spots, where n is an even integer, and the N spots are substantially equally spaced. The generation of an even number of spots is achieved using a translation symmetry in the grating design. Illustratively, the intensities of the N spots are substantially equal. Binary, multi-level, and continuous phase grating embodiments are disclosed. In the case of the multi-level and continuous embodiments, the uniform intensity is obtained using a reflection symmetry in the grating design.

Abstract: An image reading apparatus comprises a multiline sensor on which a plurality of linear sensor arrays are arranged on and a single substrate, a focusing optical system for focusing an object image on the multiline sensor. A blazed diffraction grating is disposed in an optical path between the focusing optical system and the multiline sensor, for color-separating light from the object into a plurality of light components, and for guiding the color-separated light components to the corresponding sensor arrays. The grating thickness of the blazed diffraction grating varies in correspondence with an angle of light incident on the blazed diffraction grating.

Abstract: An optical pick-up device for focusing a laser beam emitted from a light emitting element through an optical system onto a recording medium. The beam is reflected from the recording medium and redirected through the same optical system on to a photodetector. A tracking error signal and a focusing error signal are produced from the output signals of the photo-detector. A diffracting element positioned before the light emitting element and the photo-detector and produces two sub-spots in two directions for applying the so-called 3-spots method from the laser beams that were projected from the light emitting element toward the recording medium. The diffracting element is divided into a first sub-region and a second sub-region formed in the same place and defined by a parting line aligned substantially perpendicular to the track direction. The first sub-region includes a diffraction grating for diffracting three beams that comprise a main beam toward the recording medium.

Abstract: A diffractive contact lens in relief includes a smoothing layer (50) of optically transparent material having a smooth outside surface (51) and placed over the optical surface (16) in relief so as to immerse the relief.

Abstract: An artificial eye lens such as a contact lens or intra-ocular lens corrects astigmatism by two sets of substantially linear parallel zones arranged to diffract light predominantly into one order at one orientation, the spacing of the zones diminishing on either side of the linear axis. In addition circular diffraction zones may be provided to give both spherical and cylindrical power for astigmatism correction.

Abstract: A diffraction grating has incident and emitting side gratings respectively formed on front and rear faces of a diffraction substrate composed of a transparent plane-parallel plate. A pitch .LAMBDA..sub.1 of the incident side grating, a pitch .LAMBDA..sub.2 of the emitting side grating, a refractive index n.sub.1 of the diffraction substrate, a thickness t of the diffraction substrate, and incident angle .theta..sub.1 of light incident to the incident side grating, an angle .theta..sub.2 of diffraction within the diffraction substrate, an emission angle .theta..sub.3 of light emitted from the emitting side grating, a distance T from the emitting side grating to a face for receiving the emitted and diffracted light, and a wavelength .lambda. of the light are set to satisfy the following conditions.

Abstract: A diffraction grating, comprises a plurality of grooves formed by a plurality of first facets having a first set of propagative optical characteristics. All facets are generally positioned with a first orientation. A plurality of second facets have a second set of propagative optical characteristics and are generally positioned with a second orientation. The first facets are oriented to diffract light incident on them. The second facets are oriented and have propagative characteristics which prevent perturbation of the diffracted light.

Abstract: Alignment difficulties in optical computing arrangements are overcome by integrating the optical components on a single substrate and arranging the elements in a manner that causes them to interact with one another to perform the desired function. The substrate has one or two major surfaces and the elements are grown or fabricated on those surfaces using conventional integrated circuit manufacturing techniques. Most advantageously, the position-sensitive optical devices are manufactured on one side. Reflective planar optical devices are obtained by applying a reflective layer over the fabricated planar optical devices.

Abstract: There is disclosed a diffractive optical element and a method to produce same wherein the element comprises a base and at least one phase zone comprising an arbitrary multiplicity M of steps of generally identical step height, wherein M is not a power of 2. The method includes the steps of defining a basic depth unit equivalent to a zone height divided by M, defining a depth sequence of N depths wherein N is the smallest integer greater than log.sub.2 M such that each of the M steps can be produced by at least one linear combination of the N depths, defining N masks herein each mask enables the optical element to be processed to one of the N depths and wherein for each mask, the steps to be processed are those which have the one of the N depths in its linear combination and serially utilizing each of the N masks for processing of the optical element.

Abstract: A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed.

Abstract: An optical integrated circuit and an optical apparatus used in optical communication or an opto-electronics apparatus such as an optical disk recording apparatus, in which various kinds of aberration caused by wavelength variation of a light source when a semiconductor laser is used as the light source. An aberration correcting grating having such grating pitches as to nearly satisfy the Bragg condition preferably with respect to a certain wavelength of the semiconductor laser beam is used. As a result, lowering of incidence (entrance) and radiation (exit) coupling efficiencies of the grating coupler and aberration such as chromatic aberration can be prevented. Even if a multi-mode semiconductor laser is used as a light source, the characteristics of the optical integrated circuit and optical apparatus do not vary largely.

Abstract: An ophthalmic contact lens with a phase plate and a pure refractive portion within its optic zone. The invention embraces an ophthalmic contact lens of the Cohen lens design with a phase plate and a pure refractive portion within its optic zone.

Abstract: An ophthalmic lens including a carrier lens having an anterior and a posterior surface. A zone plate is having a plurality of zones is disposed annularly about the optical axis of the carrier lens on at least one of the anterior or posterior sides. Each of the zones of the zone plate is spaced from the optical axis in proportion to the square root of n, where n is the zone number. At least one echelette is disposed in each of the zones, each of the echelettes having a surface through which light propagating along the optical axis traverses. The surface of the echelettes varies in a predetermined manner from the zone nearest the optical axis to the zone furthest from the optical axis so that as the size of the aperture disposed along the optical axis changes, the relative intensity of light diffracted to desired orders changes. A step is provided between each of the echelettes, the height of each step having substantially the same optical path length.

Abstract: An optical element (12) has aspherical (14) and binary grating (16) optical surfaces. In the preferred embodiment, the optical element (12) is a positive meniscus optical element made of germanium having a useful spectral bandpass in the infrared wavelength region. A telescope (100) includes a first positive meniscus optical element (102), having a convex aspherical surface (104) and a concave binary grating surface (106). A first negative meniscus optical element (107) having a concave binary grating surface (108) and a concave aspherical surface (110) is employed. Next is a positive power lens (112), followed by a second negative meniscus lens (118). In the preferred embodiment, the first negative meniscus optical element (107) and the positive power lens (112) are affixed to a common housing (124), which is removable from the telescope system. Removal of the housing (124) converts the telescope (100) system from a wide-field-of-view telescope (100) to a narrow-field-of-view telescope (40).