Onera (Office National D'etudes Et De Recherches Aerospatiales)

Thales

Office National D'etudes Et De Recherches Aerospatiales

Onera

Jerome Primot

Nicolas Guerineau

Sabrina Velghe

Riad Haiedar

Jean-Pierre Huignard

Riad Haidar

Guillaume Druart

Laurent Lombard

Laurent Mugnier

Cindy Bellanger

Martin Piponnier

Maxime Deprez

Michel Tauvy

Sebastien Demoustier

Amaud Brignon

Ludovic Sogno

Bruno Toulon

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 (S). To achieve this, interference between two waves only is produced from beams (F, F) 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.

Wavefront sensor and method for determining differences in piston and tilt existing between several light beams

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.

Method and device for range imaging

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.

Wavefront analysis method involving multilateral interferometry with frequency difference

A laser source is disclosed with coherent recombination of N spatial monomode laser beams having N phase shifters controlled by a phase-lock device (). The phase-lock device has an optical device () capable of taking at least a portion of each of the N beams. The optical device has an optical element () capable of applying a phase deformation, and at least one matrix (M) of detectors capable of detecting a first image (im) of a wave surface corresponding to the N beams. The matrix (M) of detectors also detects a second image (im) deformed by the optical element (). Processing means () 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 (sp) corresponding to the N beams and to apply phase corrections c(&#x3c6;) to each of the N beams, by means of said N phase shifters so as to minimize the phase pistons.

Laser source with coherent beam recombination

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 surfaceS which introduces a phase shift close to 2&#x3c0;/3 (modulo 2&#x3c0;) between two adjacent secondary beams.

Compact achromatic optical interferometer of the three-wave lateral shearing type

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.

Achromatic optical interferometer, of the trilateral shift type for

Growing community of inventors

Chatillon, France

Jerome Primot