Abstract: A system and method for reading the information stored in holograms and other diffractive objects. The information is read by analyzing the diffraction pattern produced when a laser beam is focused onto a small spot on the object and scanned across the object.

Abstract: Quantum based systems for detecting materials in a sample, including biological, chemical and physical materials are described. The systems are based on exciting the sample containing the material with a femtosecond to nanosecond probe pulse of collimated light, which is tailored to optimize detection of a given material by separating the probe pulse into component features of frequency, polarization, phase and/or amplitude. The component features are independently shaped and formed into a composite pulse selected to optimize a signature response pulse received from the material.

Abstract: A system and method for reading the information stored in holograms and other diffractive objects. The information is read by analyzing the diffraction pattern produced when a laser beam is focused onto a small spot on the object and scanned across the object.

Abstract: A system and method for reading the information stored in holograms and other diffractive objects. The information is read by analyzing the diffraction pattern produced when a laser beam is focused onto a small spot on the object and scanned across the object.

Abstract: Quantum dots are used as fluorescent taggants in security inks, papers, plastics, explosives, or any other item or substance in which it is desired to provide a distinct signature or marking. Quantum dots of specific sizes, compositions and structures may be used to produce specific fluorescence, mixtures of quantum dots can be used to produce random patterns of spectrally varying fluorescence, and particular quantum dot structures can be used to provide desirable physical and optical properties. The quantum dots may be read with an optical reader, which may be combined with readers using other technologies.

Abstract: The invention provides a solid-state cooler that provides counter-current electricity flow through a device that includes Peltier junctions interconnecting the opposing flow of current through the device. The combination of counter-current flow with the Thompson,Peltier, and Seebeck thermoelectric effects provides an apparatus having the advantages of high energy efficiency, very small size and the ability to reach very low temperatures (near liquid nitrogen temperatures) with minimal energy input. The cooling apparatus is suitable for use in variety of applications, including superconductive devices such a superconductive Quantum Interference Devices (SQUID's) used in medical imaging to increase the sensitivity and resolution of NMR techniques. It is also provides a useful tool for cryosurgery apllications without the risks associated with the use and storage of liquid nitrogen. In addition, the device can be operated in the reverse to generate current from small gradients of temperature.

Abstract: A microfabrication technique, applications thereof, and mass-manufacturing techniques therefore, in which an analog mask is created and used to control exposure of a resist material to actinic radiation in order to create analog products at the microscale.

Abstract: A system and method for reading the information stored in holograms and other diffractive objects. The information is read by analyzing the diffraction pattern produced when a laser beam is focused onto a small spot on the object and scanned across the object.

Abstract: A video image viewing device includes first and second glass plates having a layer of liquid crystal therebetween. A plurality of laser diodes extending along a line near one edge of the first plate are selectively illuminated at an intensity corresponding to the amplitude of a video signal during each of a plurality of video lines. The light propagates through the first plate via total internal reflection not entering the liquid crystal layer until it reaches an area where the refractive index of the liquid crystal is selectively modified. The refractive index may be modified by selectively energizing each of a plurality of horizontal strip electrodes vertically spaced from each other. The electrodes are sequentially energized to frustrate the total internal refraction and thereby cause the light to be transmitted through the liquid crystal layer into the second plate at a location corresponding to the location of video line in a video frame of the video signal.

Abstract: A video image viewing device includes first and second glass plates having a layer of liquid crystal therebetween. A plurality of laser diodes extending along a line near one edge of the first plate are selectively illuminated at an intensity corresponding to the amplitude of a video signal during each of a plurality of video lines. The light propagates through the first plate via total internal reflection not entering the liquid crystal layer until it reaches an area where the refractive index of the liquid crystal is selectively modified. The refractive index may be modified by selectively energizing each of a plurality of horizontal strip electrodes vertically spaced from each other. The electrodes are sequentially energized to frustrate the total internal refraction and thereby cause the light to be transmitted through the liquid crystal layer into the second plate at a location corresponding to the location of video line in a video frame of the video signal.

Abstract: A method for producing durable embossing tools is disclosed. An anisotropic etching process, such as ion etching, is used to etch a relief pattern into a hard substrate. A transfer layer is formed overlaying a generally smooth, seamless surface region of a substrate. A desired relief pattern is formed in the transfer layer, by exposing a photoresist, embossing, or the like. The substrate having the photoresist thereon is subjected to an anisotropic etch. The anisotropic etch continues until the transfer layer is completely removed and the relief pattern is formed in the upper surface of the embossing tool. The relative etch rates between the transfer layer and the surface region of the embossing tool are selected to provide the desired depth modulation in the surface of the embossing tool. An embossing tool produced according to the invention has a relatively hard surface and may thus be used for the mass production of holographic images without significant degradation of the pattern.

Abstract: A security device for use on identification cards, monetary documents, and the like using a reference pattern and a message pattern each having the appearance of a random pattern of dots. The reference pattern is a dense pattern of randomly positioned dots, and the message pattern is a modulated version of the reference pattern in which the dots of the reference pattern are slightly repositioned by an amount depending on the grey value or color value of a message image at each dot location. The message image is decrypted and becomes visible with a range of grey values when it is viewed through a film transparency of the reference pattern. The dot pattern may be printed, embossed or recorded as a photograph or a hologram. Decryption of the message image may be accomplished by viewing through a contact mask, superposition of images of the message pattern and reference pattern, by viewing the message pattern through a mask positioned at a real image of the reference pattern, or like means.

Abstract: A method is disclosed for making holographic images by recording an array of pixels which together form a two or three dimensional composite image. Each pixel corresponds to a sampling of just those rays which would pass through a given point on the surface of an ordinary hologram. Every common type of hologram can be made by this method, including 2D/3D holograms, stereograms, and full color holograms. Each pixel is a white light viewable hologram generated by recording a small hologram near the narrowest part of a converging bundle of rays of coherent light, usually with each ray corresponding to one point on the object, and the rays in a pixel being confined to a horizontal plane intersecting the surface of the object.

Abstract: A method of producing color and texture effects on a surface (210,400) without the use of pigments or actual texturing. Diffraction patterns generated by interference between two light beams (220,230) are recorded in a suitable high-resolution photographic material (210,400) and are used instead of paints or inks to provide desired color and texture effects in the various regions (440,530) of an artistic or decorative composition. The resulting composition (210,400) may contain spectrally pure or mixed colors and a wide range of static or dynamic textural illusions visible under a variety of lighting conditions.

Abstract: A method of manufacturing surface relief holograms wherein an original surface relief hologram in the form of an endless loop or a drum is continuously coated with a radiation-curable resin. After curing, the resin bears a replica of the original hologram and it is continuously drawn off from the original as a sheet or film. The replica film becomes a hot-stamping foil when formed in contact with a carrier film, metallized, and coated with a hot-stamping adhesive.

Abstract: A white-light viewable, cylindrical hologram is made by recording on a cylindrical recording medium the interference between a radial reference beam and an object wavefront emanating from the center of the cylindrical recording medium. In a second step, the cylindrical hologram is placed in a flat configuration and a second hologram is recorded by recording the interference between a reference beam and an object wavefront formed by directing coherent light through the first hologram. Finally, a third hologram is formed by recording the interference between a reference beam and an object wavefront formed by directing coherent light through a narrow strip of the second hologram. The third hologram is viewed by placing it in a cylindrical configuration and directing white light onto the hologram from a point source located on the axis of the cylindrical hologram.

Abstract: A method of manufacturing surface relief holograms wherein an original surface relief hologram in the form of an endless loop or a drum is continuously coated with a radiation-curable resin. After curing, the resin bears a replica of the original hologram and it is continuously drawn off from the original as a sheet or film. The replica film becomes a hot-stamping foil when formed in contact with a carrier film, metallized, and coated with a hot-stamping adhesive.

Abstract: A method of producing color and texture effects on a surface (210,400) without the use of pigments or actual texturing. Diffraction patterns, generated by interference between two light beams (220,230), are recorded in a suitable high-resolution photographic material (210,400) and are used instead of paints or inks to provide desired color and texture effects in the various regions (440,530) of an artistic or decorative composition. The resulting composition (210,400) may contain spectrally pure or mixed colors and a wide range of static or dynamic textural illusions visible under a variety of lighting conditions.

Abstract: A method of producing color and texture effects on a surface (210,400) without the use of pigments or actual texturing. Diffraction patterns generated by interference between two light beams (220,230) are recorded in a suitable high-resolution photographic material (210,400) and are used instead of paints or inks to provide desired color and texture effects in the various regions (440,530) of an artistic or decorative composition. The resulting composition (210,400) may contain spectrally pure or mixed colors and a wide range of static or dynamic textural illusions visible under a variety of lighting conditions.

Abstract: A method of making a security device and the device are disclosed, wherein an embossable material is applied to a substrate in multiply connected regions. (A multiply connected region is one that has more than one continuous boundary). The regions have sufficient density of coverage to cause the embossable material to appear substantially continuous to the unaided eye. A diffractive pattern is embossed into a plurality of the regions and a transparent coating is applied thereover to bond firmly to the substrate and embossable material. Removal of the transparent coating results in observable damage to the security device.