Abstract: The invention relates to a detector comprising a multiple quantum well structure operating on interband or intersubband transitions by absorption of radiation having a wavelength ? having a polarization comprising a component perpendicular to the plane of the multiple quantum well structure, and comprising optical coupling means for coupling said radiation, wherein the coupling means comprise a set of first diffractive lamellar features that are distributed along at least a first direction and a set of second diffractive lamellar features that are distributed along at least a second direction, said first and second directions being mutually perpendicular and lying in a plane parallel to the plane of the multiple quantum well structure.

Abstract: The invention relates to an optical coupling structure intended to couple electromagnetic radiation to the surface of a photodetector, wherein a coupling surface paved along mutually perpendicular first and second directions by a set of N series (M1i, M2i, . . . Mni) of first features, second features, . . . nth features, the features being identical within any one series, the features being distributed along the first and second directions, the distance between the centers of two adjacent features or the inter-reticular distances between two adjacent features being variable. The subject of the invention is also a detector or a laser source comprising said coupling structure.

Abstract: A quantum well made out of a the stack of layers of III-V semiconductor materials comprises, in addition to the quantum well, an electron storage layer separated from the quantum well by a transfer barrier layer. The barrier layer has a thickness that is greater than the thickness of the quantum well by about one order of magnitude. This barrier thus enables the separation of the absorption function (in the quantum well) and the function of reading the photocarriers (in the storage layer) and therefore the limiting of the rate of recombination of the carriers, thus improving the performance characteristics of the detector.

Abstract: This optical polarimetric detector comprises: a first active detector element having a photoconductor (1) with which a first diffraction grating (3) is associated allowing incident light from a first specific polarization direction to be coupled in the first detector element and allowing the latter to detect the light having this first polarization direction; a second active detector element having a photoconductor (1′) with which a second diffraction grating (3′) is associated allowing incident light from a second polarization direction to be coupled in the second detector element and allowing the latter to detect the light having this second polarization direction. Furthermore, a detector (2) is provided making it possible to eliminate the background noise detected by previous detectors.

Abstract: A bi-functional optical detector including a first active photoconduction detection element configured to detect light within first and second wavelength ranges, a first diffraction grating associated with the first detection element and configured to couple the light within the first wavelength range so that the first active photoconducting detection element detects the light in the first wavelength range, a second active photoconduction detection element configured to detect light within the first and second wavelength ranges, and a second diffraction grating associated with the second detection element and configured to couple the light within the second wavelength range so that the second active photoconduction detection element detects the light in the second wavelength range.

Abstract: This optical polarimetric detector comprises:

Abstract: The basic idea is as follows: operational simulations of subtractive focal planes, based on the French patent No. 2 756 666, have shown that the optimal subtraction rate should not be total in order to preserve the dynamic range of the system. In this case, the low-frequency fluctuations of the temperature of the focal plane of the bias voltages will be amplified and will give rise to a fluctuation of the mean gray level of the signal at output of the multiplexer. This variation can be corrected simply by: the making of several columns of subtractive pixels without diffraction grating, for which the integrated signal is directly the residual level of the thermal current; the integration of a comparator circuit at input of the electronic card to subtract the signal generated in the reference pixels from the signals integrated into the active pixels.

Abstract: The basic idea is as follows: operational simulations of subtractive focal planes, based on the French patent No. 2 756 666, have shown that the optimal subtraction rate should not be total in order to preserve the dynamic range of the system. In this case, the low-frequency fluctuations of the temperature of the focal plane of the bias voltages will be amplified and will give rise to a fluctuation of the mean gray level of the signal at output of the multiplexer.

Abstract: This bi-functional optical detector comprises:

Abstract: The disclosure relates to a bispectral electromagnetic wave detector including at least one first and one second overlaid plane active detector elements separated by a common layer, said first and second detector elements being sensitive to the different wavelengths; a first means of connection connected in common to said first and second detector elements, a second means of connection connected to said first detector element, and a third means of connection connected to said second detector element; means for applying successively a control voltage to each means of connection; and means connected to said first means of connection to detect a photoconduction current each time a control voltage is applied. The invention is used in applications requiring detection of electromagnetic waves in two bands of different wavelengths.

Abstract: An electromagnetic wave detector having a first detector element including an active photoconducting material capable of detecting a band of wavelength and a second detector element including an active photoconducting material capable of detecting the same band of wavelength. A common layer is positioned between the first and second detector elements. A first and second connectors are configured to connect to the first and second detector elements, respectively. A third connector is configured to connect in common to the first and second detector elements. The detector further includes contact mechanisms configured to apply control voltages where the voltage applied to the third connector has a value between the values applied to the first and second connectors. A reading circuit connected to the third connector reads a photoconduction current difference between the first and the second detector elements.

Abstract: Device for the detection and processing of optical radiations, comprising at least one quantum well having asymmetric composition, said well consisting of a stack of layers of materials having differing gaps.

Abstract: Semiconductor hybrid components, especially linear infrared detectors produced by hybridization. A main substrate has integrated thereon active elements which cannot be produced on a silicon substrate. The substrate is made, for example, of AsGa, InP, HgCdTe or PbTe. Several silicon chips are mounted on the main substrate, by hybridization using indium balls. These chips include the read and multiplexing circuits. The silicon chips remain of limited size (a few millimeters) so that the differential thermal expansion stresses are limited, but the detection array may be produced as one piece without butt-joining. It is therefore possible to produce arrays of great length (several centimeters) and of high resolution (at least a thousand points).

Abstract: Disclosed is an integrated direction finder that can be used to determine the direction of a light beam and, in particular, a laser beam. This direction finder has a substrate transparent to the light beam and means on the rear face to channel a part of the light flux received on this face to the front face which has several photodetector elements. Application to optical measurements.

Abstract: A photodetector arrangement capable of detecting high-power-light flux and including a set of elementary photodetectors each one of which is individually tested to determine that it has no defects. Each of the photodetectors which is found to be free of objectionable defects is connected in parallel to a common conducting line to thus produce a combined output when radiation impinges on the detector surface. The connection can be hard wired or provided through a set of transistors acting as connection control intermediaries between the good photodetectors and the common conducting line. The active areas of only good photodetectors are thus combined to form a large photodetector area of any desired shape or size without the usual reliability problems. The selective control of the transistors can further be provided by auxiliary control photodetectors to additionally automatically control the size of the active area in response to the area of light being detected or a control light beam.

Abstract: Quantum well detector, in which the active detection zone (2) occupies only a limited area of the device and in which a diffraction grid (5) having a larger surface area than this zone thereby makes it possible to couple to it a greater light flow than that corresponding to the surface area of this zone. In this way, the sensitivity of the device is increased.Application: Detection of optical radiation.

Abstract: An electromagnetic wave detector formed of semiconductor materials includes at least one quantum well in which there is provided a fine layer of a material with a gap width that is smaller than that of the quantum well layer. For example, in the case of a GaAlAs/GaAs/GaAlAs, there is provision for a fine layer of InAs. In this way, the difference of energy levels between the two permitted levels is increased and detection of short wavelengths may be accomplished.

Abstract: An electromagnetic wave detector comprises a stack of quantum wells included between an ohmic contact and a rectifier junction which may be a barrier (Al.sub.y Ga.sub.1-y As) with a forbidden band width that is greater than that of the barriers of the quantum wells.

Abstract: An electronic bolometer comprises at least a quantum well between two barrier layers. It has an input side parallel to the quantum-well layer and receiving a beam at a quasi-normal incidence angle. Two electrodes disposed perpendicularly to the quantum-well layers allow to measure a change in the resistivity of said quantum well.

Abstract: A quantum well optical device including a layer of semiconducting material of large forbidden band width and, situated in this layer, at least one quantum well, such as a quantum line or quantum hole, of a material having a narrower forbidden band than that of the layer. This quantum well has two permitted electron levels. Means exist of assuring the electron population of the first permitted energy level.