Abstract: A method and apparatus for rapidly erasing and rebiasing a thermoptic thin film. A thermal insulating material (16) is disposed adjacent a thermoptic thin film (10). A layer of resistive material (14) is disposed between the insulating material and the thermoptic thin film and is connected to a current generator (18) which supplies a current to the layer dissipating heat into the thermoptic thin film and insulating layer. A thermal body (22), having high thermal conductivity and interfacing with the insulating layer the opposite boundary from the thermoptic thin film, contains a conduit through which a refrigerated liquid is flowed to establish a thermal gradient from the thermoptic thin film to the fluid. Sufficient current is supplied to the resistive layer to maintain the temperature of the thermoptic thin film at the bias temperature.

Abstract: A beam recombiner is used to parallelize two first order beams emanating from an magneto-optic stripe domain light deflector. One arrangement uses a concave cylindrical mirror with a negative meniscus lens attached thereon to redirect a conjugate beam. The other arrangement uses a concave cylindrical mirror with a cylindrical rod lens placed at the radius of curvature of the mirror to redirect the conjugate beam.

Abstract: Responsive to a plurality of parallel light beams and electric signals corresponding to the parallel light beams, an acoustic modulation element produces output light beams modulated by acoustic waves resulting from the electric signals. The element comprises a single acoustooptic medium block receiving the parallel beams on a first surface thereof and emitting the output light beams from a second surface opposite to the first surface. A plurality of transducer units are laid in parallel on a third surface of the block between the first and the second surfaces along the respective parallel beams so as to propagate the acoustic waves into the block when activated by the electric signals. The block may have a fourth surface opposite to the third surface and arcuately or triangularly recessed towards the third surface.

Abstract: An antireflective optical film exhibits a quintic refractive index profile with an initial refractive index n.sub.L as close as possible to the refractive index of the incident medium and a final refractive index n.sub.H substantially equal to the refractive index of the substrate. The refractive index profile of the film may be defined by the relationship:n(x)=n.sub.L +(n.sub.H -n.sub.L) (10 (x/T).sup.3 -15( x/T).sup.4 +6( x/T).sup.5)where N(x) is the refractive index of the film at a depth x in the film relative to the incident surface of the film and T is the thickness of the film. The film may also be fabricated as a plurality of layers, with each layer substantially thinner than wavelengths within the spectral band. Each layer within the plurality is divided into a sublayer pair, including a first sublayer with the refractive index n.sub.L and a second sublayer with the refractive index n.sub.

Abstract: In order to prevent ambient light severely reducing the contrast of a display on a tricolor cathode ray tube, a holographic element having reflection wavelength peaks between the emission wavelength peaks of the cathode ray tube is disposed in the light path from the display to the observer. The holographic plane of reflection is preferably inclined to the substrate plane of the element so as to direct unwanted light away from the observer. The display may be head-down or head-up.

Abstract: An electronically tunable optical filter using acousto-optic interaction in a dispersive birefrigent crystal. The strong wavelength dispersion of birefringence in a class of uniaxial semiconductors near the band gap is utilized to enhance the spectral resolution of the tunable acousto-optic filter. The dispersive tunable acousto-optic filter provides a very large aperture while maintaining an extremely narrow bandwidth.

Abstract: An acousto-optic modulator for a high speed/high resolution raster output scanner, the modulator have a substrate composed of substantially pure gallium phosphide, with a relatively thin high frequency transducer comprised of a piezo electric layer sandwiched between metal electrodes and employing a conformable adhesive to prevent distortion of the crystal or transducer.

Abstract: A ferroelectric focussing and defocussing device for operation at millimeter wavelengths applicable for use as a component in radar systems. Electrodes direct fields reversibly and continuously modify the refractive character of the ferroelectric material of the device as incoming radiation seeks to proceed along the optic axis of the material. The device includes first and second material media sharing complementary sides with Fresnel contours.

Abstract: An optical spatial frequency filter of the type having a pair of birefringent elements with means for changing the polarization state of light between them is given a substantially color dependent spatial frequency response. The filter comprises a wavelength dependent means for changing the polarization state of light between the birefringent elements such that the polarization state of light of a first color is changed by a first amount and the polarization state of light of a second color is changed by a second amount sufficiently different from the first amount such that the spatial frequency response of the spatial frequency filter is substantially color dependent. The filter is particularly useful with a color image sensor of the type having a first sampling frequency in a first color and a second sampling frequency different from the first in a second color.

Abstract: An electrically dimmable rear-view mirror for motor vehicles of simple and robust construction, suitable for use as an outside mirror or as an interior mirror possessing a transmission layer which is composed of a PLZT ceramic, on which a linear birefringence can be imposed by means of a controlling electric field. The transmission layer is located between a linear polarizer and a reflective layer, the latter being designed as a dielectric multilayer arrangement. Suitable comb-type electrodes are located on that side of the reflective layer which faces away from the transmission layer and, if appropriate, on that side of the polarizer which faces the transmission layer, the function of these comb-type electrodes being to generate the controlling field. The polarizer defines the direction of polarization, which is inclined at 45.degree. with respect to the field direction and/or the optical axis of the transmission layer.

Abstract: A document includes a substrate which has an outer surface and defines a plane, and a coordinate system which is defined with respect to the plane. A diffraction-optical authenticating element covers at least part of the outer surface, and generates at least one color pattern constituting a visually testable feature which verifies the authenticity of the document. The diffraction-optical authenticating element provides a color pattern moving at a predetermined velocity along a predetermined track when the document is illuminated from a first direction and viewed from a second direction, as defined with respect to the coordinate system, upon the document being rotated within the plane along a prearranged sense of rotation, and at a prearranged velocity.

Abstract: An optical element comprises a transparent substrate. An antireflection coating is provided on the substrate for reducing reflections of wavelengths from approximately 700 nm to approximately 1700 nm. The coating comprises a plurality of stacked, uniform layers with refractive indices which decrease toward the top of the stack. A base coating is arranged between the layer stack and the substrate. The effective refractive index at the top of the base coating is at least 2.5, and the base coating is a graded index layer.

Abstract: In the representative embodiments described herein, an attenuator of optical radiation, and specifically high-intensity laser radiation, comprises a plurality of diffracting sheet members, containing a plurality of apertures, disposed at an angle to the incident radiation. The sheet members may be wire screens and the attenuator may include a plurality of such screens disposed at different angles and having different mesh orientations.

Abstract: To assure a durable bonded joint between the two substrates on which the respective electrodes of an electrochromic device are joined together by an adhesive to form a cavity between them for an electrolyte, a baked-on layer of polyvinyl alcohol or polyvinyl butyral is provided to promote adhesion, allowing a commercially available two-component adhesive to provide a firm joint even if the non-transparent substrate is of metal. The adhesion promoting coating is also used to line the cavity, except where the electrodes are, thus providing insulation and chemical isolation which is important, at least for the metal substrate. The electrolyte is filled through a hole in the metal substrate, which is thereafter plugged with a low-melting solder.

Abstract: A magneto-optic storage media which utilizes two layers or films of magnetic material, with the magneto-optic hysteresis loop of one of the films being of a sense opposite to the sense of the magneto-optic hysteresis loop of the other film. The media permits the Farraday effect polarization rotations produced by one of the magnetic films to be in phase with Kerr effect polarization rotations produced by the other of the magnetic films, such that additive mode conversion is provided from different portions of the media whereby the detected signal has an increased signal-to-noise ratio.

Abstract: A transducer plate having at least two mounting zones separated by a transverse groove of a depth greater than the desired thickness of the transducer plate obtained after polishing the mounted transducer plate, and a method for mounting the transducer plate to an optical medium to form an acousto-optic device are disclosed.

Abstract: A long period buried optical grating is fabricated by polishing a number of single crystal silicon wafers to identical thicknesses and flat figure, applying a light reflective metallic coating to the wafers, thereafter bonding the wafers together in a stack, and thereafter lapping the resulting stack of bonded layers at an acute angle with respect to the major planar surfaces of the wafers to form the buried grating, such grating having optically flat reflective sawtoothed elements. The grating period may be readily controlled by changing the acute angle and/or the thickness of the silicon wafers.

Abstract: The invention relates to electro-optical media which make it possible to record holograms in real time. It consists in using a lamina of a selected material such as bismuth-silicon oxide, this lamina being subjected to a transverse electric field perpendicular to the fringes of the hologram to be inscribed, and in illuminating this lamina with a light beam which is not coherent with the two object and reference beams which interfere within this lamina.

Abstract: This rotationally symmetric optical sensor consists of six lens elements e selectively of the alkali halide materials KBr, C I, and KI. It has a wide field-of-view coverage of 60 degrees and operates in the middle infrared through the far infrared bands and extends well into the extreme infrared band. The combination of optical materials selected to be used effectively corrects the chromatic and monochromatic aberrations of the sensor.

Abstract: Apparatus for optically coupling a plurality of optical fibers in predetermined combinations. Each optical fiber fits into and is supported by an expanded-beam type optical component that is optically structured to collimate, or nearly collimate, the output from an optical fiber when the fiber is located at, or nearly at, the focus of the optical component. The optical components fit into a housing that is adapted to receive and support them such that at least one of the components is nominally aimed in a first direction and the other optical components are nominally aimed in a direction different from the first direction.