Abstract: Disclosed are methods and apparatus for at least one of authenticating, sorting or counting documents, as well as to security structures contained within documents and to documents containing security structures. A security device or structure includes an optical gain medium and a structure having boundaries that impart an overall geometry to the structure that, in combination with at least one material property of the structure, supports an enhancement of electromagnetic radiation emitted from the gain medium for favoring, in one embodiment, the creation of at least one mode that enhances an emission of electromagnetic radiation within a narrow band of wavelengths. Suitable, but not limiting, shapes for the structure comprise elongated, generally cylindrical shapes such as filaments, a sphere shape, a partial-sphere shape, a toroidal shape, a cubical and other polyhedral shape, and a disk shape.

Abstract: A method is disclosed for obtaining information about an object, as is a system operating in accordance with the method. The method includes steps of (a) placing a plurality of regions onto the object, each region being capable of emitting a predetermined wavelength of light; (b) detecting the light; and (c) decoding information from the detected light. At least one of the regions contains semiconductor particles having a radius larger than a quantum dot radius for a corresponding semiconductor material, and a chemical composition selected to provide the predetermined wavelength of light. The semiconductor material contains at least one of a Group II-IV alloy, or a Group III-V alloy, or a compound comprised of an indirect bandgap material, such as Si or Ge. The concentrations of the alloy or compound constituent elements are preselected to provide the predetermined emission wavelength. The semiconductor material may further include a selected dopant.

Abstract: A multi-spectral imager and the applications of same for the marking and coding of, for example, textiles, linens, garments, documents and packages for high-speed machine identification and sortation. Specific uses include garment and textile rental operations, laundry operations, and the postal and mail sortation of documents and packages. Methods and apparatus are provided to identify items via information encoded within an applied mark, as well as a novel mark reading/decoding scheme. A method is disclosed for printing fluorescent marks on an item, such as a heat-sealable label, to generate a unique identification number or indicia, as well as a reader system for reading applied marks.

Abstract: Disclosed are methods and apparatus for at least one of authenticating, sorting or counting documents, as well as to security structures contained within documents and to documents containing security structures. A security device or structure includes an optical gain medium and a structure having boundaries that impart an overall geometry to the structure that, in combination with at least one material property of the structure, supports an enhancement of electromagnetic radiation emitted from the gain medium for favoring, in one embodiment, the creation of at least one mode that enhances an emission of electromagnetic radiation within a narrow band of wavelengths. Suitable, but not limiting, shapes for the structure comprise elongated, generally cylindrical shapes such as filaments, a sphere shape, a partial-sphere shape, a toroidal shape, a cubical and other polyhedral shape, and a disk shape.

Abstract: A multi-spectral imager and the applications of same for the marking and coding of, for example, textiles, linens, garments, documents and packages for high-speed machine identification and sortation. Specific uses include garment and textile rental operations, laundry operations, and the postal and mail sortation of documents and packages. Methods and apparatus are provided to identify items via information encoded within an applied mark, as well as a novel mark reading/decoding scheme. A method is disclosed for printing fluorescent marks on an item, such as a heat-sealable label, to generate a unique identification number or indicia, as well as a reader system for reading applied marks.

Abstract: A method and system for detecting a presence of more than one item at a point along a conveyance path, comprising steps of (A) generating a light beam and directing the beam through the path such that a presence of the item will cause the beam to be attenuated; (B) detecting the beam after it is attenuated by the presence of the item; and (C) determining from the amount of attenuation how many items are simultaneously present. In the preferred embodiment the item is an item of currency, and the step of generating a light beam includes a step of operating an optical source, such as an LED or a laser, to generate a beam having a wavelength in the range of about 400 nm to about 1 micrometer or longer.

Abstract: A multi-spectral imager and the applications of same for the marking and coding of, for example, textiles, linens, garments, documents and packages for high-speed machine identification and sortation. Specific uses include garment and textile rental operations, laundry operations, and the postal and mail sortation of documents and packages. Methods and apparatus are provided to identify items via information encoded within an applied mark, as well as a novel mark reading/decoding scheme. A method is disclosed for printing fluorescent marks on an item, such as a heat-sealable label, to generate a unique identification number or indicia, as well as a reader system for reading applied marks.

Abstract: In a first aspect this invention provides a security article comprising an electrically actuated optical switch comprised of a liquid crystal material. In one embodiment the liquid crystal material is disposed in a layer of polymer dispersed liquid crystal material. In a second embodiment the liquid crystal material is micro-encapsulated with an orientable dye. In a second aspect this invention provides a document or currency that comprises a paper matrix that includes at least one security article, i.e. a security thread. In a third aspect this invention provides a device for verifying an authenticity of a document or currency of a type that includes at least one security article, i.e. at least one security thread. The at least one security thread includes the liquid crystal material having a visual characteristic that is switched between two states as a function of a presence or absence of an electric field between first and second electrodes.

Abstract: This invention teaches an optical source (10) for performing photomedicine. The optical source includes a Nd:YLF laser (12) having an output providing light having a wavelength of 1.053 micrometers; a frequency doubler (13) that is optically coupled to the laser output for converting a portion of the light to frequency doubled light, the frequency doubler having an output providing frequency doubled light having a wavelength of 526.5 nm; coupled to the output of the frequency doubler, a unit (14) for shifting the frequency doubled light to light having a longer wavelength of about 630 nm; and means (16) for conveying the light having the longer wavelength to the region of tissue. In one embodiment of this invention the shifting unit includes a device for performing stimulated Raman scattering of the frequency doubled light.

Abstract: Disclosed is a method for generating an image of a selected area of tissue, the method includes steps of: (a) providing a fluorescent photosensitizer compound in combination with a hydrogen-containing solvent to the selected area of tissue; (b) generating acoustic energy for generating free radicals from the solvent; (c) reacting the free radicals with an oxalate ester to generate a key intermediate; (d) transferring chemical energy to the fluorescent photosensitizer compound from the key intermediate; (e) activating the fluorescent photosensitizer compound with the transferred energy to emit long wavelength light; and (f) detecting the long wavelength light to generate the image of the selected area of tissue. In one embodiment the oxalate ester is comprised of ester bis (2,4-dinitrophenyl) oxalate (DNPO). In one application, a selected area of living tissue is analyzed to identify an abnormality within the tissue.

Abstract: A substrate (10) has a surface (10A) containing at least one photolithographically defined feature (12, 14A, 14B) for containing a gas or fluid of interest. The substrate further includes at least one region (10B) containing a selected optical gain medium in combination with scattering particles or sites for generating light having a desired wavelength in response to a pump source, such as a laser (20) or a lamp. The at least one region is optically coupled to the at least one photolithographically defined feature for illuminating a portion of the sample with the light having the desired wavelength. The substrate may be comprised of a glass, a polymer, or a semiconductor. In one embodiment at least one optical waveguide (16) is formed in the substrate for conveying light from the pump source to the region containing the gain medium and scatterers.

Abstract: A high efficiency, narrow spectral linewidth lasing pixel device that implements a low-voltage spatially patterned variable loss element placed inside an optically pumped high-gain laser cavity is disclosed. The output properties of this system make it useful for digital projection displays.

Abstract: A method and apparatus for identifying articles is disclosed. The method includes steps of: (a) providing a plurality of articles, each of the articles having at least one portion that includes a photonically active material; (b) for each article, illuminating the at least one portion with light from a stimulus source; (c) identifying a location of the at least one portion by detecting an emission from the photonically active material; (d) pointing an excitation source at the identified location; and (e) illuminating the at least one portion within the identified location with light from the excitation source. A next step detects an information-encoded emission from the photonically active material in response to the light from the excitation source. An optional step (g) sorts the articles based on the detected emission.

Abstract: An improved scratch card instant lottery ticket includes micro-encapsulated chemical reactants which, when released, irreversibly form one of a visual color change or a fluorescence signature at a location of the card. Both the visual color change and fluorescence signature indicate that the location has been played. Scratch cards are also marked to indicate that they have been read. Cards are marked by either automatically activating chemical reactants to form a visual color and a fluorescence signature, heating a thermofluorescent material to alter a fluorescence signature, or applying a heat-responsive material to the scratch card in such that when the identification code is read, an altered material is detected. Also taught are a method and apparatus for evaluating the scratch card to determine which locations on the card have been played.

Abstract: A structure generates electromagnetic radiation having at least one wavelength selected for activating a photosensitive substance that is applied to a tissue to be treated. The structure is particularly useful for photodynamic therapy (PDT) applications. The structure includes a body of material, such as a polymer filament, band, or substrate, that contains a gain medium. The gain medium in turn contains a substance (such as dye molecules) for generating a stimulated emission that includes the at least one wavelength when excited by a pump wavelength, and a plurality of scattering sites (such as scattering particles) for scattering the stimulated emission to provide a narrow band emission at the at least one selected wavelength. The narrow band emission in turn activates the photo-sensitive therapeutic substance.

Abstract: An aqueous system for the production of metal chalcogenide nanocrystalline salts such as zinc selenide, from a hydrolyzable chalcogen carbonyl compound, such as selenourea, by simple hydrolysis thereof under alkaline conditions in the presence of water soluble metal hydroxide, such as zinc hydroxide in the form of the zincate ion, i.e., Zn(OH).sub.4.sup.-2. Selenourea contains selenium in the correct oxidation state, is inexpensive, commercially-available and readily hydrolyzable under aqueous basic conditions in the presence of the zincate ion to form zinc selenide. The zinc selenide is insoluble in the alkaline aqueous vehicle and precipitates over time in the form of nanocrystallites or quantum dots of the zinc selenide.

Abstract: A class of high efficiency (e.g., .gtoreq.20%) materials for use as display pixels to replace conventional phosphors in television, monitor, and flat panel displays. The materials are comprised of nanocrystals such as CdS.sub.x Se.sub.1-x, CuCl, GaN, CdTe.sub.x S.sub.1-x, ZnTe, ZnSe, ZnS, or porous Si or Ge alloys which may or may not contain a luminescent center. The nanocrystals may be doped with a luminescent center such as Mn.sup.2+ or a transition metal. The nanocrystals have passivated surfaces to provide high quantum efficiency. The nanocrystals have all dimensions comparable to the exciton radius (e.g., a size in the range of approximately 1 nm to approximately 10 nm). A quantum dot nanocrystal display phosphor that has a size selected for shifting an emission wavelength of a constituent semiconductor material from a characteristic wavelength observed in the bulk to a different wavelength.

Abstract: A structure generates electromagnetic radiation having at least one wavelength selected for activating a photo-sensitive substance that is applied to a tissue to be treated. The structure is particularly useful for photo-dynamic therapy (PDT) applications. The structure includes a body of material, such as a polymer filament, band, or substrate, that contains a gain medium. The gain medium in turn contains a substance (such as dye molecules) for generating a stimulated emission that includes the at least one wavelength when excited by a pump wavelength, and a plurality of scattering sites (such as scattering particles) for scattering the stimulated emission to provide a narrow band emission at the at least one selected wavelength. The narrow band emission in turn activates the photo-sensitive therapeutic substance.

Abstract: An optical source (10) for exciting a photosensitive drug that responds to light within a predetermined band of wavelengths. The optical source uses a chemiluminescent source in combination with at least one fluorescer selected to output light within the predetermined band of wavelengths. The chemiluminescent source can be flowed during use. In one embodiment the chemiluminescent source is stored in a heated reservoir, and is pumped from the reservoir through a conduit, such as a catheter. A patch can be used for spreading the chemiluminescent source over a wider area. An active feedback system can also be used for controlling the output light. In preferred embodiments a plurality of reactants are mixed for forming a chemiluminescent source in combination with at least one fluorescer selected to output light within the predetermined band of wavelengths.

Abstract: This invention teaches an optical source (10) for performing photomedicine. The optical source includes a Nd:YLF laser (12) having an output providing light having a wavelength of 1.053 micrometers; a frequency doubler (13) that is optically coupled to the laser output for converting a portion of the light to frequency doubled light, the frequency doubler having an output providing frequency doubled light having a wavelength of 526.5 nm; and, coupled to the output of the frequency doubler, a unit (14) for shifting the frequency doubled light to light having a wavelength of about 630 nm. In a presently preferred embodiment of this invention the shifting unit includes a device for performing stimulated Raman scattering of the frequency doubled light for creating the third Stokes line at 630.1 nm. The device includes a crystal comprised of a R.sub.x (MO.sub.3).sub.y compound and means for establishing a multi-pass or resonant cavity optical configuration through the crystal.