Abstract: A system and method for authentication of secure products is disclosed. The security feature contains a first component in the form of an emitter capable of emitting light in response to external pump light. The security feature also contains a second component in the form of a taggant that absorbs light in a spectrally narrow range compared to the broader excitation spectrum of the first material. In this manner the emitter and taggant work in combination with one another to create an emission response significantly dependent on the illumination wavelengths and unique to the specific combination of the components. The emitter and taggant can be in the form of a mixture. Further the emitter and taggant may be applied in close proximity to one another, such as within two separate coating layers on a suitable substrate.

Abstract: Systems and methods for document and product authentication are provided using a combination of interacting absorption and emission materials that are formed into covert optically encoded markings. The markings are formed from at least one emitter and at least one absorber, that exhibit a first emission in response to a first excitation of the emitter and a change in that emission in response to excitation of the absorber such that various combinations of emitter and absorber materials create a machine readable response that cannot be detected by the human eye.

Abstract: Disclosed are security articles and methods and systems for authenticating security articles using a plurality of stimuli. According to one embodiment, an illustrative security feature includes an encoded feature wherein differential activation of phosphorescent or fluorescent materials creates a machine readable code through the simultaneous presence of a source of electromagnetic radiation and a specific gas environment. A detector detects a differential spectral emission across the security feature that results from the change in gas environment. The spectral emission may be compared to an expected emissive signature to determine authenticity of the security article.

Abstract: Self-cleaning banknotes are provided using coatings, inks and additives which are photo-active and catalytic to reactions which are effective in breaking up organic contaminants or dirt to allow for the self-cleaning of banknotes by ambient light exposure as well as the cleaning of processed banknotes using equipment with more intense optical excitation, thus increasing their usable life. The invention is usable with all substrates and particularly polymeric substrates such as biaxially-oriented polypropylene (BOPP). The invention further discloses a system which allows a certain class of fitness parameters to cause these banknotes to be redirected to a cleaning module, be reevaluated, and then either returned to circulation or rejected and/or destroyed. In addition, inks which are photo-catalytic can be used for extending the life of the banknotes in printed regions.

Abstract: A device is disclosed for the application of customizable indicia to the outer surface of a smoking article such as a cigar. The device employs thermal means to apply indicia in a controlled and customized manner that allows easy branding of cigars. The device includes a thermal branding head, a cradle for holding the smoking article, a heating element, a control circuit to control the temperature of the heating element and branding head, an actuator to move the branding heat into contact with a cigar contained within the cradle and a timing circuit to determine how long the branding head shall be in contact with the cigar.

Abstract: A system and method for authentication of secure products is disclosed. The security feature contains a first component in the form of an emitter capable of emitting light in response to external pump light. The security feature also contains a second component in the form of a taggant that absorbs light in a spectrally narrow range compared to the broader excitation spectrum of the first material. In this manner the emitter and taggant work in combination with one another to create an emission response significantly dependent on the illumination wavelengths and unique to the specific combination of the components. The emitter and taggant can be in the form of a mixture. Further the emitter and taggant may be applied in close proximity to one another, such as within two separate coating layers on a suitable substrate.

Abstract: A metallic nano-particle surrounded by an amplifying medium results in a boundary condition that creates a singularity in the particle's dynamic polarizability at the localized surface plasmon resonance and at a critical value of the gain is disclosed. The boundary condition may be time dependent due to excitation by a sub-picosecond laser pulse and couples to the electromagnetic vacuum resulting in photon emission in an analogue of the Unruh Effect. The vacuum emission from 2-D nanostructures embedded in high gain laser dyes predicts energies nearly two orders of magnitude larger than the spontaneous emission background. The vacuum radiation is may have a unique dependence on the excitation.

Abstract: A film for surface enhanced raman scattering may be utilized for chemical and biological sensing. The film includes a polymeric layer, and a metallic nanoparticle having a cross-section, the metallic nanoparticle being embedded in the polymeric layer. The polymeric layer has a thickness less than a largest straight line through the cross-section of said metallic nanoparticle. The polymeric layer is selected from a group of absorbing media and amplifying media, and the metallic nanoparticle may be gold. The metallic nanoparticle may also be a shape selected from a group of spheroids and rods.

Abstract: A marking system that includes forming at least one marking in or on an article, wherein the image formed is not visible to the unaided human observer, and further contains at least one digital watermark. The digitally watermarked image comprises emissive and photoabsorptive portions. The digitally watermarked image is applied using a substance reactive to a predetermined excitation source, and exposure to ultraviolet light. Other traditional techniques, such as printing with fluorescent inks may be used in combination. The digitally watermarked image is subsequently observable upon exposure to the predetermined excitation source. The digitally watermarked image may be observed and decoded by appropriately configured detection systems, wherein the information obtained may be used for purposes including, but not limited to, authentication and security of the article or information contained within the article.

Abstract: A rechargeable photovoltaic cell. In one embodiment the photovoltaic cell includes a first electrode with a transparent substrate having a porous high surface area titanium dioxide layer thereon, and including a light absorbing dye. The rechargeable cell also includes a second electrode which includes a transparent electrically conductive substrate arranged in spaced apart relationship with the first electrode so as to define a gap with the first electrode. A re-sealable seal provides access to the gap from the exterior of the cell. An electrolyte solution is located within the gap. Another aspect of the invention relates to a method of recharging a photovoltaic cell. In one embodiment the method includes draining the first electrolyte solution from gap in the photovoltaic cell, flushing the first electrolyte solution from the gap, drying the gap, and filling the gap with a second electrolyte solution all through a re-sealable seal.

Abstract: Described herein are systems and methods for digital data encryption, and more specifically, systems and methods for providing encryption keys for reading encrypted data. Optical media, particularly digital disks, are described where a laser reader accesses digital data on a disk. The disks are coated with a coating containing an encryption key to access encrypted data in the digital disk.

Abstract: A method for generating plasmon-polariton or phonon-polariton resonance effect including: providing structure capable of plasmon resonance; providing gain medium; and placing the structure in close juxtaposition to the gain medium. In one embodiment the structure has dimension D and is placed within distance less than or equal to D to, or within or partially within, the gain medium. The invention concerns material for enhanced plasmon resonance including gain medium; and structure capable of such resonance in close juxtaposition to the gain medium. In one embodiment the structure has a plasmon absorption curve, the gain medium has a gain curve and the peak of the plasmon absorption curve lies within the gain curve. The invention concerns a device for enhanced plasmon resonance including gain medium; structure capable of plasmon-polariton or phonon-polariton resonance in close juxtaposition to the gain medium; and a device for stimulating such resonance in the structure.

Abstract: A method for enhancing the light detection capabilities of a chromophore. In one embodiment the method includes the steps of providing a plasmon resonant nanoparticle and placing the nanoparticle in close juxtaposition to the chromophore. In one embodiment the chromophore includes 11-cis-retinal and the nanoparticle is a metal such as gold. In one embodiment the chromophore is chlorophyll. In another aspect the invention relates to an enhanced rhodopsin having a chromophore and a plasmon resonant nanoparticle in close juxtaposition with the chromophore. Yet another aspect of the invention is a method of enhancing vision in an eye including providing a plasmon resonant nanoparticle and placing the nanoparticle in close juxtaposition to a retinal molecule in the eye.

Abstract: A plasmon enhanced particle for use in a photovoltaic cell. The particle includes a nanostructure capable of plasmon resonance; a charge accepting semiconductor in conjunction with the nanostructure; and a sensitizer coating the charge accepting semiconductor. Another aspect the invention relates to a plasmon enhanced solar photovoltaic cell. The solar photovoltaic cell includes a plurality of nanoparticles capable of plasmon resonance; a plurality of nanoparticles of charge accepting semiconductor in conjunction with the nanoparticles capable of plasmon resonance; and a coating of sensitizer on the plurality of nanoparticles of charge accepting semiconductor. Another aspect relates to a method of making a plasmon enhanced material suitable for use in a photovoltaic cell.

Abstract: A pixel that includes a plurality of plasmon nanoparticles is provided. In certain examples, the pixel is configured to transmit or to reflect a variable wavelength of light with varying concentrations of plasmon nanoparticles. Displays including the pixels are also disclosed. An ink which includes plasmon nanoparticles is also provided.

Abstract: A pixel that includes a liquid crystal material and one or more of an anisotropic nanoparticle and an anisotropic nanostructure is provided. Displays including the pixel are also disclosed. An ink which includes a liquid crystal material and one or more of an anisotropic nanoparticle and an anisotropic nanostructure is also provided.

Abstract: A method and an apparatus are disclosed for limiting the readability of optically-readable medium, wherein a combination of a liquid crystal material and a wavelength shifting material are incorporated into the optically-readable medium. The liquid crystal material is selected to substantially interfere with the reading beam of a reading device. The wavelength shifting material is selected to shift the wavelength at which the liquid crystal interferes with the reading beam so that the reading beam can read the optically-readable medium. A predetermined stimulus causes the liquid crystal material to shift back to a configuration that substantially interferes with the reading beam so that the reading beam can no longer read the content on the optically readable medium.

Abstract: A solid state Raman laser includes a laser pump for producing a first radiation at a high power and at a first wavelength along an optical path, a solid Raman active medium in the optical path of the first radiation, the medium including single crystal diamond having a first surface and a second surface, where the first radiation at a high power produces stimulated Raman scattering in the medium and the medium generates a second radiation at a second wavelength, a first optical element in the optical path of the first radiation, wherein the first optical element allows the first wavelength to be transmitted and allows the second wavelength to be reflected, and a second optical element in the optical path of the first radiation, wherein the second optical element allows the first wavelength to be transmitted and allows the second wavelength to be reflected.

Abstract: Methods and apparatus are provided for making an optically readable media unreadable and tamper-resistant. A method is disclosed for making an optically readable media unreadable, as is a media that operates in accordance with the method. The method has steps of (a) providing the media with a readout surface layer that is non-flat (i.e., textured in some way, such as by embossing, scratching, depositing a non-planar layer or regions, such as droplets) and that inhibits optical readout of the media; (b) applying a coating layer to the non-flat surface layer to smooth the non-flat surface and to enable optical readout of the media; and, after an initiation of a readout period, (c) removing the coating layer so as to expose the non-flat readout surface layer, thereby inhibiting optical readout of the media. Preferably, the coating layer is substantially index matched to the readout surface layer.

Abstract: A method is disclosed for making an optically readable media (20) unreadable. The method includes steps of providing the media having a readout layer (22, 23) having features that encode information; forming over the readout layer a reactive layer (302) that inhibits a readout device from reading the information; and forming over the reactive layer a reaction inhibiting layer (304) comprising a volatile substance that inhibits transport through the reaction inhibiting layer until the volatile substance is lost to the environment. The reactive layer may contain a solvent and a dye and may be a color-forming layer that is responsive to a loss of the solvent. The solvent of the color-forming layer may comprise 1,5-dimethyl-2-pyrrolidinone (DMP), or it may comprise N-methyl-pyrrolidinone (NMP). The reaction inhibiting layer may also contain a solvent, such as any transparent, non-absorbing solvent. Glycerol is one suitable example.