Abstract: The invention relates to optically active coatings for improving the yield of photosolar conversion, consisting of a transparent matrix containing a plurality of optically active constituents absorbing the light energy in a first absorption wavelength lambdaA1 and reemitting the energy in a second wavelength lambdaR1 different from lambdaA1, said optically active constituents being selected such that the reemission wavelength lamdaR1 of at least one type of constituent corresponds to the absorption wavelength lambdaA2 of at least one second type of constituent, characterised in that the C2/C1 ratio of concentration C1 of the optically active constituents of a first type in relation to the concentration C2 of the optically active constituents of said second type is between 0.13 and 0.26; Ci designating the concentration in moles per liter of the constituent i in relation to the doped matrix.

Abstract: The invention relates to method for rendering sustainable the electromagnetic characteristics of optically active composite materials, said method comprising: a first step of preparing doped organic compounds by mixing at least one type of optically active molecules with a protective material in order to prevent the contact thereof with photodegradation-inducing elements and the migration of the optically active molecules; a second step of producing optically active nanoparticles including said doped organic compounds; and a third step of producing optically active composite materials by incorporating the optically active nanoparticles into a polymer matrix.

Abstract: The invention relates to optically active coatings for improving the yield of photosolar conversion, consisting of a transparent matrix containing a plurality of optically active constituents absorbing the light energy in a first absorption wavelength lambdaA1 and reemitting the energy in a second wavelength lambdaR1 different from lambdaA1, said optically active constituents being selected such that the reemission wavelength lamdaR1 of at least one type of constituent corresponds to the absorption wavelength lambdaA2 of at least one second type of constituent, characterised in that the C2/C1 ratio of concentration C1 of the optically active constituents of a first type in relation to the concentration C2 of the optically active constituents of said second type is between 0.13 and 0.26; Ci designating the concentration in moles per litre of the constituent i in relation to the doped matrix.

Abstract: A photovoltaic generator including at least one photovoltaic cell, and a transparent matrix placed with at least one optically active material with an absorption wavelength &lgr;a and a reemission wavelength &lgr;r, the optically active material selected such that &lgr;a corresponds to a range of the photovoltaic cell with a lower sensitivity than &lgr;r, the matrix having an input surface and an opposite surface and comprises a reflecting coating an a dichroic filter on the input surface that substantially reflects wavelengths longer than about 950 nm and is substantially transparent for wavelengths less than about 950 nm, and on the opposite surface the matrix has a reflecting coating that reflects wavelengths greater than about 400 nm, and wherein the photovoltaic cell is included in the matrix.

Abstract: A photovoltaic generator including at least one photovoltaic cell, and a transparent matrix placed with at least one optically active material with an absorption wavelength &lgr;a and a reemission wavelength &lgr;r, the optically active material selected such that &lgr;a corresponds to a range of the photovoltaic cell with a lower sensitivity than &lgr;r, the matrix having an input surface and an opposite surface and comprises a reflecting coating an a dichroic filter on the input surface that substantially reflects wavelengths longer than about 950 nm and is substantially transparent for wavelengths less than about 950 nm, and on the opposite surface the matrix has a reflecting coating that reflects wavelengths greater than about 400 nm, and wherein the photovoltaic cell is included in the matrix.

Abstract: This invention relates to a process for setting up several data paths on a single optical transmission fiber, including a modulation step consisting, for each data path, of modulating a light source with a specific wave length by signals corresponding to said data path, a step transmitting the modulated light signals to a mixer and a step of chromatically separating the light signals transmitted by the optical fiber, characterized in that the signals are multiplexed by an integrating sphere coated on the inside with a reflecting surface and including a plane reflector oriented perpendicular to the axis of the transmission optical fiber.

Abstract: The countermeasure process in the field of target evaluation and laser range finding consists in coating at least a portion of a missile with a doped material that absorbs at least a portion of the incident laser beam and reemits a diffuse radiation in a different waveband.The reemission wave length preferably corresponds to an absorption spectrum band of the atmosphere. A portion of the reemitted signal can be used to trigger an alarm.This invention also covers the materials for the implementation of the countermeasure process, they are made of a matrix that is doped with photoluminescent substances. Applications: varnish, paints, canopies, helmet vizors.

Abstract: The present invention relates to a covering element comprising (i) an organic matrix and (ii) luminescent doping materials, scintillating doping materials or mixtures thereof, which form at least one light cascade absorbing electromagnetic radiation in at least one first predetermined wavelength band in order to re-emit the same in at least one second predetermined wavelength band; and (iii) a diffusing material.

Abstract: The present invention relates to the authentication of fiduciary or security objects, such as official documents, contracts, banknotes, credit cards and computer diskettes.The object to be authenticated is marked with a matrix composed of an organic resin of the vinyl or acrylic type, or any other similar resin, incorporating a series of sparkling doping materials and a series of photoluminescent doping materials with long-lasting remanence.This marking is carried out by coating, transfer of a film, printing, or integration of particles into the fiduciary material. The document marked in this manner can, in addition, be covered with a substance which is transparent in the visible spectrum going from UV to IR with the exception of a given wavelength band.The object marked in accordance with the invention has a first color in daylight, a second color when it is submitted to ultraviolet radiation and a third color from long-lasting when it is placed in darkness.

Abstract: A luminescent solar radiation concentrator is disclosed. Incident radiation of flux .phi..sub.1, and wavelength .lambda..sub.1, impinges enclosure wall V.sub.1 having a double index of refraction n.sub.1, n.sub.2 (where n.sub.2 >n.sub.1) and then is absorbed by cascade fluorescent concentrator/converter CL, which isotropically re-emits fluorescent radiation at wavelength .lambda..sub.2 and flux .phi..sub.2 (where .lambda..sub.2 >.lambda..sub.1, and .phi..sub.2 >.phi..sub.1) which then is absorbed by a solar photovoltaic cell. The double index of refraction wall prevents escape of fluorescence radiation from the enclosure.