Abstract: An optical pickup device to be used in a system for optically playing back recorded information comprises a diffraction grating or a hologram lens instead of a prism for directing a read-out light beam emitted by a light source to the surface of the recording medium and separating a reflection beam reflected by the surface of a recording medium from the read-out light beam. By the elimination of the prism, the size of the pickup device is substantially reduced and the production cost of the device is also reduced.

Abstract: A spatial light modulator having a lattice of microgrooves formed on the surface of the silicon photodiode nearest the electro-optic cyrstal to prevent lateral charge transfer at this surface.

Abstract: A pair of planar electrodes spaced from one another by an electrolyte. The front electrode faces the air or vacuum environment and is transparent, and the second electrode is in thermal contact with a heat conducting surface and is reflective. By selectively modifying the voltage between the two electrodes, a partially reflective coating can be deposited on the back face of the front electrode or removed therefrom. With the coating removed, the emission of thermal radiation is minimized, and a major portion of the radiation from sources in the environment is reflected. With the coating present, emitted or reflected radiation interacting with the coating interferes destructively with the radiation emitted or reflected by the second electrode, maximizing thermal emission and absorbing a major portion of any incident radiation.

Abstract: A diffusing screen (50, 50', 50", 102) of a transmission hologram (54, 80, 94, 112) located adjacent to a diffraction optics directional diffusing screen (52, 86, 92, 114) supresses zero-order light from the diffusing screen thereby providing a device having the advantages of a directional diffusing screen but which does not have the disadvantages associated with zero-order light.

Abstract: A unitary assembly of a hologon scanner disc or spinner, a motor for rotating the disc and a lens for focusing the deflected laser beam on an image surface. A housing including a base plate and a cover removably mounted on the base plate, encloses the hologon disc. The base plate has a surface with respect to which the position of the hologon disc and lens is referenced. The cover has a platform on which lenses are interchangably mounted, such that, each lens has the correct position and orientation with respect to the entrance pupil of the scanner system. The hologon disc is also removably mounted on the shaft of the motor and referenced against a shoulder of the shaft which is precisely spaced with respect to the reference surface of the base plate of the housing. The hologon deflector facets of different discs which are mounted on the shaft always have the same alignment with respect to the lens and the laser beam which is incident thereon.

Abstract: A Faraday rotator assembly includes a Faraday rotator of an optically transparent magnetic material; a device for applying a first magnetic field to the Faraday rotator, which field saturates the Faraday rotator with reversible magnetization; and a device for applying a second magnetic field to the Faraday rotator, the field having a direction different from that of the device for applying the first magnetic field to the Faraday rotator. The magnetization in the Faraday rotator is maintained in a saturation state by the second magnetic field at least during the reversal of the direction of the first magnetic field. The angle of the Faraday rotation of the Faraday rotator is reversed by reversing the direction of the first magnetic field.

Abstract: In this invention, an optical lens element (L1) receiving a wave beam from a common laser source radiating a spherical wave beam and a full reflection mirror (MR) having a small window (W) are employed. This spherical wave beam is irradiated through the small window (W) of the full reflection mirror (MR) onto a hologram record medium (HR1) as a subject wave beam (A). Also, another wave beam from the source is reflected by the full reflection mirror (MR) is simultaneously irradiated onto the hologram record medium (HR1) as a reference wave beam (B). Thus, an inline hologram lens (IN-L) is produced having a large numerical aperture.

Abstract: A reflection controllable view mirror device having an electro-optical assembly which changes its optical transmittance to vary quantity of light passing therethrough in accordance with the magnitude of the applied voltage, a control circuit to control the transmittance at a value so as to ensure predetermined uniform reflection under circumstances permitting transmittance to deviate from inherent one because of deterioration or the like. Another control circuit is provided to control to ensure the inherent transmittance for predetermined reflection under the same circumstances.

Abstract: The invention concerns a method of producing optical elements, in particular filters, with interference layers comprising alternately slightly refractive and highly refractive dielectric layers deposited on a substrate S. The first layer 1 applied to the substrate is Al.sub.2 O.sub.3, constituting a slightly refractive layer, after which further layers 2 to n of ZnS and Al.sub.2 O.sub.3 are applied in an alternating sequence. The last layer n consists of Al.sub.2 O.sub.3. Such layers can be applied, at low temperatures, on flat substrates and, in particular, on sharply curved substrates. Production costs are reduced, and these layers possess the optical properties of known interference layers however resistance to external influences is greatly increased. In the case of mineral substrates, the coatings also offer considerable resistance to boiling.

Abstract: An optically-generated or computer-generated holographic diffusing screen usable in bringing an image to focus thereon is a hologram which upon reconstruction displays a substantially transparent annulus on a substantially opaque background. The annulus preferably has an outer diameter substantially equal to the exit pupil of the image-forming lens, which image is to be focused. The radial width of the transparent annular portion is very small relative to the outer diameter of the annulus. The holographic diffusion screen may be formed by making a holographic image of the substantially annular pattern or by exposing a holographic plate with two collimated mutually coherent beams of light, one beam being perpendicular to the plate while the other is at an angle with respect to the first beam, rotating the holographic recording plate a predetermined amount, and repeating the exposing and rotating steps until a predetermined number of exposures has been completed.

Abstract: An `eye-piece` system for a non-Galilean afocal infra-red telescope designed to contribute to astigmatism correction, pupil match, and true afocality without undue increase in objective aperture requirements comprises a positively powered back group and a negatively powered front group consisting of a rear lens element with a convex rear surface and a front lens element with a concave front surface, there being a negatively powered gas lens between the rear and front elements of the front group. The objective system may be catadioptric.

Abstract: An apparatus and method for recording and displaying a three-dimensional image is disclosed. A high resolution, thick film emulsion (50) is positioned in contact with a phase-conjugate mirror (60). The emulsion (50) is exposed to light from a light source (20) which is reflected off of a three-dimensional object (30). Upon exposure to the light from the light source (20) each ray of light (10) will transverse the emulsion (50) and be reflected from the phase-conjugate mirror (60) so as to exactly retrace its path back through the emulsion (50). The incident light waves (10') and their reflected light rays (70') will expose the emulsion (50) in the form of an interference pattern or wave form (80'). Once exposed, the emulsion (50) is developed in the customary manner. The developed emulsion (100) will pass only light rays of a frequency (color) and direction similar to that which the emulsion (50) was originally exposed. Accordingly, a three-dimensional image is displayed to the viewer (130).

Abstract: A phase retardation element, for use in an optical data storage system, which provides a 90.degree. phase difference between two perpendicular polarized components of an incident wave with a single internal reflection from a surface coated with a thin film of dielectric or metal material.

Abstract: A set of safety goggles (20) for adjustably attenuating the intensity of optical radiation at any selected wavelength produced by a variable-wavelength laser (e.g., a dye laser) comprises a pair of oculars, both of which can be tuned to any particular wavelength producible by the laser. Each ocular comprises a birefringent filter, which includes stationary components including a polarizer (11), a wide-field element made up of a half-wave plate (13) sandwiched between multiwave plates (12 and 14), and a quarter-wave plate (16), and rotatable components including a polarizer (18). The wide-field element causes an optical path difference between orthogonal components of a single polarization state. The quarter-wave plate (15) and the rotatable polarizer (18) in combination enable selection of any particular wavelength whose intensity is to be attenuated.

Abstract: This invention is to a three dimensional active vision sensor. This invention uses a multifacet holographic scanner to move a laser spot across an object at high speed in a raster pattern and a digital position detector to give a highly accurate, low noise, digital representation of the angle to the laser spot on the object. The integration of these two devices is a unique solution for providing range (3-dimensional data) of an arbitrary object in real time.

Abstract: A polarizing plate is disclosed, comprising a polarizing film and a protective layer bonded through an adhesive layer to at least one surface of the polarizing film, wherein the protective layer is a polyester film in which the minimum or maximum refractive index in a direction in parallel with the plane of the film is nearly equal to that in the direction of the film thickness and the retardation is at least 10 .mu.m. On this polarizing plate, colored interference fringes are not formed at all even if it is looked at from any direction. Thus, the polarizing plate is suitable for use in the circumstance that it is exposed to the air, or in a display wherein a liquid crystal is used.

Abstract: An optical scanner uses frequency modulation and detection techniques to produce and utilize multiple, simultaneous scan patterns in which corresponding scan lines have different focal lengths. Two or more solid state lasers are modulated at unique frequencies. The frequency modulated output beams pass through different combinations of focusing lenses and are deflected by a single beam deflecting apparatus. Light reflected from any scanned object is detected. The resulting multi-frequency signal is applied to a plurality of bandpass filters to separate the returned signal into a plurality of separately decodable signals.

Abstract: A phase-only optical filter capable of being utilized within a phase-only optical correlation system. The phase-only optical filter is made by mathematically generating preselected phase-only information by a fast Fourier Transform technique. This generated phase-only information is transferred onto an unexposed holographic film. Thereafter, the film is developed and subsequently bleached. The resultant bleached film is the phase-only filter which, when utilized in a correlation system, provides substantially 100% utilization of the source of electromagnetic radiation during the correlation process.

Abstract: The invention relates to a compound blazed optical phase grating. The grating comprises at least two grating sections which are disposed opposite each other in parallel planes. The gratings have grooves which extend parallel to each other. The grating sections have equal grating periods and are movable relative to each other within their planes and perpendicular to the grooves. Over one grating period, the optical path length varies at least substantially parabolically and symmetrically relative to the grating period. The path length varies in such a manner that when both grating sections are symmetrically arranged relative to a common line perpendicular to the grating planes, the optical path length through the compound grating is uniform across the grating. Various optical switches and switching matrixes can be formed by using such compound phase gratings.