Abstract: The conventional grating is substituted by one or more curved prisms in a concentric spectrometer of the type derived from the Offner mirror objective. The curved prisms are known as Fery prisms. The deviations from the concentric form are used as a corrective device. The spectral apparatus is especially suited as an imaging spectrometer having a detector array because the two-dimensional image can be formed in the direction of the spatial coordinate as well as the spectral coordinate without distortions and curvatures.

Abstract: A spectral imager or spectrophotometer-type optoelectronic camera including an optical system, a CCD-type set of photosensitive elements (3) at the focus of the optical system, a transparent protective window (5) arranged in front of the sensitive face (4) of the set of photosensitive elements (3), and a spectral disperser (1) allowing spectral analysis of the scene observed by the camera. The sensitive face (4) of the set of photosensitive elements (3) that points toward the protective window is coated with a monolayer or multilayer coating of anti-reflection material (9) whose thickness (e) varies continuously as a function of the wavelength of the light received by the sensitive face, parallel to the dispersion axis of the disperser (A).

Abstract: A scanning optical device for emitting and receiving which embodies an optical source adapted to emit a primary beam along an emission axis, a deflecting mirror arranged on an emission axis so as to intercept and deflect the primary beam, a telescope having an optical axis and a detector on this axis, and a scanning mirror mounted so as to rotate around a scan axis coaxial with the optical axis of the telescope and exhibiting a non-zero inclination with respect to the optical axis, wherein the optical source is positioned opposite to the telescope with respect to the scanning mirror, the emission axis being coaxial with the telescope optical axis, the deflecting mirror being fixed to the scanning mirror, and arranged at 90.degree. with respect to the scanning mirror within a central opening provided in the scanning mirror.

Abstract: A two-channel multiplex Fourier transform spectrometry interferometer device comprises two semi-reflecting mirrors substantially in alignment with each other between two reflecting surfaces substantially parallel to each other and to a mean plane containing the semi-reflecting mirrors. At least one of the mirrors and surfaces is inclined by a non-zero amount to the mean plane. The algebraic sum of the inclinations of the semi-reflecting mirrors relative to the mean plane is different than the sum of the inclinations of the reflective surfaces relative to said plane. At least one prismatic blade means with an index of refraction different than that of the remainder of the interferometer device is disposed between one of the semi-reflecting mirror and one of the reflective surfaces. The algebraic differences of the prismatic blade angles are different to either side of the mean plane. For earth spectrometry the device is mounted on an aircraft or a satellite, for example, moving relative to the earth.

Abstract: An interferometry device for Fourier transform multiplex spectrometric imaging designed to move relative to an object-zone according to a direction of motion constituting a reference direction for said interferometry device. The device includes a prismatic block of transparent material having a first and a second input/output face meeting in a block edge, a semitransparent plate inside said block, and first and second reflective surfaces forming a roof and arranged facing respectively the first and the second input/output face via the semitransparent plate. The device further has at least one slanted dioptrical separation surface with a dioptry angle (.alpha.) provided between one of the input/output faces and the corresponding reflective surface, and the deviation of the angles of inclination (.beta., .beta.') of the first and second rooflike reflective surfaces relative to the corresponding input/output face is non-zero.

Abstract: Light source for an optical detector of the position of a body, the latter being measured by the relative position(s) of spots of light projected by the source on a linear detection element. Said source is in the form of a flat luminous geometric figure comprising a curve (23,23',24,24') symmetrical about an axis (22). Said curve is symmetrical about an other axis (21) and has at least a first thickness (e.sub.1) on one side of a first (21) of the two axes, and at least a second thickness (e.sub.2) on the other side of said axis. Application to an optical device for measuring the angular position of a body.