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: An optical bistable photorefractive crystal device is provided in which a photorefractive crystal disposed between two mirrors is uniformly illuminated by a light beam, a signal beam being focused on a given portion of the crystal to cause bistable switching of this portion inside the crystal.

Abstract: Beam-scanning of an antenna by means of microwave phase shifts is achieved by N electrooptical modulators which receive two collinear beams having different frequencies. The modulators define optical paths having different wavelengths. N photodetectors make it possible to receive the beams reflected by the modulators and to control antenna elements during a 2 .pi. phase excursion.

Abstract: A device for establishing optical connection links between electronic component cards forming part of a package. The device comprises a transparent plate having parallel faces and a light source which emits a divergent beam and is implanted on a first card. The beam is reflected from a first optical diffracting element in the form of a collimated beam which undergoes multiple reflections from alternate reflecting elements to a second optical diffracting element and is converted by the second element to a convergent beam transmitted to a detector which is implanted on a second card.

Abstract: An optical device for storing a coherent image in a multimode cavity makes use of two interaction media in which photoinduced phase gratings are recorded. By way of example, these media are photorefractive media. A first wave designated as an object wave travels through the cavity and interferes in each of these two media with a pumping wave in order to permit energy transfer from the pumping wave to the first wave.

Abstract: A device is provided for the prolonged illumination of an object from an initial transitory illumination. This device comprises a laser whose cavity is closed by two total reflection mirrors; in the path of the intra-cavity radiation is disposed a photoexcitable interaction medium with index variation in the volume of which the transitory signal wave coming from the object and the intra-cavity radiation interfere; this interference generates in real time an index strata grating which diffracts a complex conjugate wave of the signal wave which returns to the object.

Abstract: This optical Fourier transformer device supplying the correlation function of two motifs of an object illuminated in coherent light by using the double diffraction principle is essentially characterized in that it generates a complex wave conjugate of a wave modulated by the object propagating in the opposite direction to the latter. This conjugate wave is produced by double diffraction in an interaction medium and compensates the distortions induced by the optical components of the system. The optical correlator system utilizing this Fourier transformer is essentially characterized in that it uses a recyclable material as the recording medium. A reading beam is subject to an angular scan making it possible to optimize the diffraction efficiency of this medium. The beam modulated by the object and the reading beam are synchronously deflected to improve the signal to noise ratio in the output plane.

Abstract: A display device is provided using a liquid crystal layer associated with a photoconducting plate, in which the voltage applied to the valve is an AC voltage chosen so as to transfer to the liquid crystal a maximum signal, and that applies more especially to radioscopy and to the projection of coherent (laser reading) or incoherent images.

Abstract: A camera in accordance with the invention comprises a coherent light source from which is formed an object illuminating beam and a pumping radiation beam, and an interaction medium for receiving the pumping wave and the imaged wave reflected from the illuminated object. This medium diffracts in real time a replica of the imaged wave which is reflected from the object.

Abstract: This invention concerns a process for producing diffracting phase structures in an interaction medium, which is formed of microballs of material in suspension in a polymerizable liquid. When illumination rings have been recorded by the interference of two light waves, they are fixed in situ by exposing the mixture to ultraviolet radiation.

Abstract: An optical observation system in accordance with the invention comprises illumination means by scanning the object and means for detecting the radiation diffracted by the object. It also comprises an interaction medium in which the wave emerging from the object interferes with a pumping wave in order to induce in it a system of layers diffracting in real time a replica of the object wave propagating in the direction of said wave and a complex conjugate wave propagating in the opposite direction. These waves, which are isomorphic of the object wave help to improve the detection of the object.

Abstract: An optical system for recording n information signals on a photosensitive tape in the form of a discontinuous track made up of parallel track sections by means of n light beams having a two states modulated intensity, being simultaneously deflected by an acousto-optical deflector and focusing on the tape in the form of n equidistant spots aligned in a direction x. The combination of the deflection and a translation movement of the tape produces a scanning movement of said n spots in a direction perpendicular to x. The same system is made for the reading of the information transcribed on the tape, the beams being then not modulated, by means of photodetector means which receive the light emerging from the tape and provide information signals in relation with the physical modifications obtained on the tape during the recording.