Abstract: A wavefront analyzer is modified to simply determine the differences in amplitude and tilt which can exist between the different regions of an initial wavefront (S0). To achieve this, interference between two waves only is produced from beams (F1, F2) which come from neighboring regions on the initial wavefront. Such an analyzer can be used to coherently combine laser radiation produced by different sources arranged in parallel. Another use is for the determination of the differences in height and inclination which exist between the neighboring mirror segments of a Keck telescope.

Abstract: A wavefront analyser is modified to simply determine the differences in amplitude and tilt which can exist between the different regions of an initial wavefront (S0). To achieve this, interference between two waves only is produced from beams (F1, F2) which come from neighbouring regions on the initial wavefront. Such an analyser can be used to coherently combine laser radiation produced by different sources arranged in parallel. Another use is for the determination of the differences in height and inclination which exist between the neighbouring mirror segments of a Keck telescope.

Abstract: A method for range imaging allows determining respective distances to multiple objects, based on a single image. The image is captured through a component having a transmittance function of which the Fourier transform is inscribed on a circle within a plane of spatial frequencies. A Fourier transform of the captured image is calculated in order to obtain a total spectrum for the image content. The distance to each object is then calculated based on several homothetic superimpositions of a reference spectrum with the total spectrum, so that said reference spectrum coincides with a portion of the total spectrum each time.

Abstract: A method for range imaging allows determining respective distances to multiple objects, based on a single image. The image is captured through a component having a transmittance function of which the Fourier transform is inscribed on a circle within a plane of spatial frequencies. A Fourier transform of the captured image is calculated in order to obtain a total spectrum for the image content. The distance to each object is then calculated based on several homothetic superimpositions of a reference spectrum with the total spectrum, so that said reference spectrum coincides with a portion of the total spectrum each time.

Abstract: The method comprises positioning a diffraction grating with a two-dimensional meshing on the path of the beam to be analyzed and processing at least two interferograms of at least two different colors, each interferogram being obtained in a plane from two sub-beams with different diffraction orders. The invention can be used to analyze and correct divided wavefronts.

Abstract: A laser source is disclosed with coherent recombination of N spatial monomode laser beams having N phase shifters controlled by a phase-lock device (3). The phase-lock device has an optical device (30) capable of taking at least a portion of each of the N beams. The optical device has an optical element (32) capable of applying a phase deformation, and at least one matrix (M1) of detectors capable of detecting a first image (im) of a wave surface corresponding to the N beams. The matrix (M1) of detectors also detects a second image (imd) deformed by the optical element (32). Processing means (31) are provided for processing the first and second images. The processing means are configured so as to measure the phase pistons between on the sub-pupils (spj) corresponding to the N beams and to apply phase corrections c(?) to each of the N beams, by means of said N phase shifters so as to minimize the phase pistons.

Abstract: A method and a system for analyzing the wavefront of a light beam, wherein a diffraction grating is arranged in a plane perpendicular to the light beam to be analyzed and optically conjugated to the analysis plane. Different emerging beams of the grating interfere to generate an image having deformations linked to the gradients of the wavefront to be analyzed. The method is characterized in that the grating carries out the multiplication of an intensity function which is implemented by a two-dimensional grating with hexagonal meshing of surface S transmitting the light of the beam to be analyzed into plural emerging beams arranged in a hexagonal meshing, by an phase function which is implemented by a two-dimensional grating with hexagonal meshing of surface 3S which introduces a phase shift close to 2?/3 (modulo 2?) between two adjacent secondary beams.

Abstract: A laser source is disclosed with coherent recombination of N spatial monomode laser beams having N phase shifters controlled by a phase-lock device (3). The phase-lock device has an optical device (30) capable of taking at least a portion of each of the N beams. The optical device has an optical element (32) capable of applying a phase deformation, and at least one matrix (M1) of detectors capable of detecting a first image (im) of a wave surface corresponding to the N beams. The matrix (M1) of detectors also detects a second image (imd) deformed by the optical element (32). Processing means (31) are provided for processing the first and second images. The processing means are configured so as to measure the phase pistons between on the sub-pupils (spj) corresponding to the N beams and to apply phase corrections c(?) to each of the N beams, by means of said N phase shifters so as to minimize the phase pistons.

Abstract: The application relates to a method for analyzing the wave surface of a light beam from a source to the focus of a lens. The beam illuminates a sample on the analysis plane and having a defect. A diffraction grating of the plane is a conjugate of an analysis plane through a focal system. An image is formed in a plane at a distance from the grating plane and analyzed by processing means. The invention encodes this grating by a phase function resulting from the multiplication of two phase functions, a first exclusion function defining a meshing of useful zones transmitting the beam to be analyzed in the form of light pencil beams, and a second phase fundamental function which creates a phase opposition between two light pencil beams coming out of adjacent meshes of the exclusion grating.

Abstract: A method and a system for analyzing the wavefront of a light beam, wherein a diffraction grating is arranged in a plane perpendicular to the light beam to be analyzed and optically conjugated to the analysis plane. Different emerging beams of the grating interfere to generate an image having deformations linked to the gradients of the wavefront to be analyzed. The method is characterized in that the grating carries out the multiplication of an intensity function which is implemented by a two-dimensional grating with hexagonal meshing of surface S transmitting the light of the beam to be analyzed into plural emerging beams arranged in a hexagonal meshing, by an phase function which is implemented by a two-dimensional grating with hexagonal meshing of surface 3S which introduces a phase shift close to 2?/3 (modulo 2?) between two adjacent secondary beams.

Abstract: The method comprises positioning a diffraction grating with a two-dimensional meshing on the path of the beam to be analyzed and processing at least two interferograms of at least two different colors, each interferogram being obtained in a plane from two sub-beams with different diffraction orders. The invention can be used to analyze and correct divided wavefronts.

Abstract: In a nonlinear optical medium such as the gallium arsenide, two collinear incident monochromatic waves are injected to generate a monochromatic wave. The medium induces between the three waves a propagation phase-shift that has a value ? if the three waves travel a coherence length in the medium and that is compensated at the value 0 modulo 2? each time that the three waves have travelled a periodic distance in the medium. In order to significantly increase the conversion efficiency, the periodic distance between two successive bounces of total internal reflection of the waves in zig-zag is strictly less than the coherence length. The high conversion efficiency on a very short material length leads to product high-power coherent optical sources particularly with wavelengths of approximately 10 ?m.

Abstract: A device for analyzing the wave surface of a light beam has an entry lens which defines a reference plane, optically conjugate with the plane in which the wave surface of the light beam is analysed. A bidimensional meshed lattice is placed in this reference plane, perpendicularly to the beam. The different sub-beams, due to the different orders of diffraction, are focused jointly by a first lens, in an intermediate focal plane, in the vicinity of which a mask selects, from the sub-beams, those which relate to at least three distinct orders of diffraction. A second lens takes the selected sub-beams to a nil-sensitivity plane, conjugate with the plane of the lattice. An interference image is observed in a working plane, situated at a chosen distance from the nil-sensitivity plane. The device can be characterized as an improved achromatic optical interferometer, of the trilateral shift type.