Abstract: An instrument (1) for characterizing an optical system, includes: at least one primary source (3) for emitting an illumination light beam (FE); an optical device for directing the illumination beam (FE) onto the optical system (L) to be characterized; a wave front analyzer (4) adapted for receiving a beam from the optical system (L); and a unit for processing the measure signals from the wave front analyzer (4), adapted for providing characterization information of the optical system (L). The instrument further includes a scattering member (22) substantially provided in the focal plane of the optical system (L) so as to create a secondary source generating a secondary beam flowing through the optical system (L) and further directed towards the wave front analyzer.

Abstract: Method for shielding a high-power laser apparatus (S) in which a laser beam is generated and then amplified in at least a first amplification stage, including spatial filtering (4) of the amplified laser beam, phase correction (3) carried out on the laser beam before it is spatially filtered, and a measurement of the aberrations (7) on the laser beam. The phase of the beam is corrected so as to produce a beam having minimal aberrations after spatial filtering. The shielding device (D, D?) implementing this method may in particular be employed in apparatus using an intense laser beam of high (terawatt) peak power and in proton therapy units.

Abstract: A wavefront analysing device, of the Hartmann or Shack-Hartmann type, comprises in particular a set of sampling elements arranged in an analysis plane, and forming as many micro-lenses for sampling the incident wavefront, and a diffraction plane wherein are analysed the Airy discs of the different micro-lenses illuminated by the incident wavefront. The shape of each micro-lens is such that the associated diffraction figure has in the diffraction plane one or several preferential axe(s), and the microlenses are oriented in the analysis plane such that the preferential axe(s) of the diffraction figure of a micro-lens are offset relative to the preferential axes of the diffraction figures of neighbouring micro-lenses, thereby enabling to limit the overlapping of the diffraction figures.

Abstract: A device for the analysis of an optical wavefront includes an array (ML) of microlenses (Li), and signal processing elements. Each mircolens (Li) defines a subaperature (Spi), and focuses an elementary surface of the wavefront, intercepted by the subaperature, for forming a spot (Ti) on the detector. For each subaperature (Spi), a zone (Zi) of assumed localization of the spot is defined. The processing unit makes it possible to establish a measurement file associating to each subaperature the position of this spot. The structure of the array (ML) presents one or several local variations. By comparing the contribution of these local variations taken from the measurement file, with their contribution taken from a reference file, the displacement between the subaperature from which a detected spot is derived and the subaperature that defines the zone of assumed localization wherein the spot is located is measured.

Abstract: A method and device for measuring optical wavefront shape parameters based on line-by-line analysis of the wavefront are disclosed. The method comprises at least one step (ACQi) consisting of acquiring a wavefront line. The acquisition comprises detecting (DETi) the line for delivering an electric signal characterizing it, for example, by means of a detection module including, in particular, an array of microlenses and a sensor, the module capable of being mobile in rotation and/or in translation. The acquisition comprises a step (Tsi) for processing the signal for determining a set Ki of parameters, for example, values proportional to the wavefront phase values measured on the line. In an embodiment, the method further comprises a step (RECi) for reconstructing each wave line consisting, for example, in expressing the line phase on a base of orthogonal polynomials, then a step (RECs) for reconstructing the wavefront on the basis of the reconstructed lines.

Abstract: The invention concerns an optical device for the contactless measurement of the distance of a light source (4) comprising optical detecting means (7) consisting of elementary sensors and further comprising: a set of N imaging means (SP1, SP2, SP3), N≧3, that enable image acquisition of the light source on a plane in the proximity of the detecting means thereby forming with said means a set of hot spots, each spot spreading over at least two elementary sensors; a circuit for computing, on the basis of the relative positions of at least three hot spots, at least one characteristic parameter of the distance from the light source whereof the accuracy depends on N number of hot spots. The measuring device is characterized in that it is designed for industrial measurements (of dimensions, texture, position, vibrations, displacement).