Abstract: A device for analyzing plants, by luminous excitation and fluorescence measurement, can be used on site without preparation of the plants. The device evaluates the content of a compound in the skin or epidermis of a plant. The geometry of the device is characterized by a direction of the excitation light rays and a direction of the fluorescence light rays which are non-collinear with each other. The device includes several sets of emitters of different wavelengths, each including several emitters, and makes it possible to measure a plurality of excitation-fluorescence combinations. A method for evaluating and monitoring the development and maturity of a crop, as well as a method for monitoring and controlling plant treatment are also described.

Abstract: A method and a system for jointly determining the content of a first chromophorous and fluorescent compound and a second chromophorous compound in a biological tissue (30). The determination of the content of the chromophorous and fluorescent compound (33) is carried out by optical measurement of the differential absorption of this chromophorous and fluorescent compound (33) and the determination of the content of the second chromophorous compound (34) is carried out by optical measurement of the fluorescence of the chromophorous and fluorescent compound (33). Optical radiations (11-14) are utilized which are suitably chosen in combination with at least one operation of filtering these radiations suited to using single detection (21) and measurement element for the two determinations.

Abstract: A method and a system for jointly determining the content of a first chromophorous and fluorescent compound and a second chromophorous compound in a biological tissue (30). The determination of the content of the chromophorous and fluorescent compound (33) is carried out by optical measurement of the differential absorption of this chromophorous and fluorescent compound (33) and the determination of the content of the second chromophorous compound (34) is carried out by optical measurement of the fluorescence of the chromophorous and fluorescent compound (33). Optical radiations (11-14) are utilized which are suitably chosen in combination with at least one operation of filtering these radiations suited to using single detection (21) and measurement element for the two determinations.

Abstract: A device for analyzing plants, by luminous excitation and fluorescence measurement, can be used on site without preparation of the plants. The device evaluates the content of a compound in the skin or epidermis of a plant. The geometry of the device is characterized by a direction of the excitation light rays and a direction of the fluorescence light rays which are non-collinear with each other. The device includes several sets of emitters of different wavelengths, each including several emitters, and makes it possible to measure a plurality of excitation-fluorescence combinations. A method for evaluating and monitoring the development and maturity of a crop, as well as a method for monitoring and controlling plant treatment are also described.

Abstract: A phase conjugation mirror including a non-linear medium (1) and a focusing lens (2), in which a beam to be reflected (F1) is displaced relative to a non-linear medium. The displacement is obtained through displacement of the focusing lens and has application in the stabilization of the reflectivity of a phase conjugation mirror.

Abstract: A non-linear optical fiber receives two light waves by its two ends, each light wave being modulated by means of two modulators. These light waves create photoinduced index variations in the fiber which are proportional to the intensity of the optical field. A reading source emits a reading wave in the fiber. This reading wave is reflected at least partially by the index variation or variations. A detector receives the reflected wave and makes it possible, through the computation of the returning time of the wave, to determine the position of the index variations. Applications: very wide passband signal correlators.

Abstract: Disclosed is a spatial light modulator of the type associating a layer of liquid crystal (2) with a layer of a photoconductive material (1), the photoconductive material being based on polysilane or polygermane.

Abstract: Disclosed is a laser source with beam scanning, of the type comprising: a pump laser source emitting a pump beam with a determined wavelength; a pressurized gas cell receiving the pump beam and emitting, by Raman effect, an output beam with a wavelength called a Stokes wavelength; a control light source transmitting a control beam to the gas cell, this control beam having a wavelength that is substantially equal to the Stokes wavelength; wherein said light source includes means for the spatial and/or temperal modification of the injection of the control photons of the control beam into said cell constituted by a multiple-laser strip structure, forming a power slave laser and cooperating with means for modifying the radiation pattern of said multiple-laser strip structure, so as to prompt the emission of the output beam in a variable direction.

Abstract: Disclosed is a laser pulse generator in which a single pulse is generated from a train of pulses. The amplitude of this single pulse is the addition of the amplitudes of the pulses of the train of pulses. This addition is done in a non-linear crystal inserted in an optical loop. The train of pulses takes the place of a pump wave applied to the non-linear crystal and the signal circulating in the optical loop takes the place of a signal wave. This signal wave therefore benefits from a transfer of energy coming from the pump wave because of the interaction in the non-linear crystal.

Abstract: The aim is to provide a new power laser configuration enabling the delivery of a beam of high spatial quality with an optimum efficiency of extraction of energy. It can be applied, more particularly, to Q-switch solid-state lasers, in doing away with recourse to specific elements for compensation of aberrations. The structure of emission of a power pulsed laser signal, of the type comprising, firstly, an oscillator stage with low-level output beam and, secondly, a power amplifier stage, is characterized in that the power amplifier stage is formed by a laser amplifier that produces a pump beam cooperating with distinct means for energy transfer without phase transfer from said pump beam towards said low-level beam coming from the oscillator.

Abstract: This invention relates to deflection cells for laser beams. A deflection cell according to the present invention essentially comprises a deflector such as of the "acoustooptical" type, to deflect a low-power incident laser beam, and a system to make that deflected low-power incident beam, in a nonlinear Brillouin diffusion medium 11 like a gas such as methane (CH.sub.4), xenon, sulfur hexafluoride (SF.sub.6), or a liquid such as carbon disulfide (CS.sub.2), acetone, work with a high-power laser pump beam, forming a nonzero angle ".theta." with the deflected beam. Application, in particular, to telemetry and missile guidance for which the laser beam used as reference should be able to undergo orientation changes which are quick and in a large angular field.

Abstract: This invention relates to power laser generators in which it is possible to control the angular direction of output laser beams. The generator according to the present invention is characterized by the fact that it successively comprises on the same optical axis of propagation, a pilot laser beam generator to generate a laser beam wavelength, a controllable deflector, a beam separator, a laser amplifying medium with the wavelength of the pilot beam, and a phase conjugation nonlinear mirror. The laser generator is applicable, in particular, to missile guidance systems or in telemetry systems.