Abstract: An actively phase matched waveguide structure suitable for use as a frequency doubling device is described. The phase matching of the waveguide is controlled by application of a control voltage. The waveguide includes first and second non-linear optical layers of material having differing indexes of refraction forming a waveguide. Disposed on the surface of the waveguide is a layer of transparent semiconductor material disposed between two transparent electrodes. The index of refraction of the transparent semiconductor material varies with the potential applied to the electrode and thereby varies the phase matching of the waveguide as a whole.

Abstract: A charged particle beam apparatus comprising a particle source for generating a particle beam to irradiate a specimen located in a field space of a particle lens of the apparatus is provided with an auxiliary particle source for generating a particle beam of low energy particle to be injected into the lens field space and to be directed to the surface of the specimen by the same lens field.

Abstract: A photomultiplier tube comprising a photocathode (10), focusing electrodes (12, 12') and a fast multiplier structure (20) having a large input surface relative to the photocathode and comprising at least one input dynode (21). According to the invention, said photomultiplier tube comprises, between the photocathode (10) and said focusing multiplier structure (20), a first multiplier stage (30) comprising, in succession and viewed from the assembly consisting of the photocathode (10) and the focusing electrodes (12, 12'), a grid (31), a first multiplier dynode (32) of the apertured-plate type, and an extracting grid (33) having the same pattern as said first multiplier dynode (32), the output of the extracting grid (33) being coupled to said input dynode (21) of the multiplier pattern by means of a focusing electrode (40).

Abstract: A capacitor having at least one dielectric layer present between each time a flat electrode and an opposite electrode, in which the electrode(s) and the opposite electrode(s) are staggered with respect to each other so that in the plane of each time one of two opposing end faces of the capacitor they terminate in the same plane and are contacted there by means of external connection contacts, in which at least one electrode in its end area adjacent the external connection contact associated with it comprises a window and that the non-contacted end(s) of the opposite electrode(s) extend(s) in the area of the window(s).

Abstract: Apparatus and methodology for mapping the superconductive properties of a sample of superconducting material. The material is cooled so that it is a mixed state and an alternating magnetic field is induced in a portion of the sample to be tested. The harmonic component of the induced alternating magnetic response is measured at a location proximate to the point of induction. As the inducing and measuring devices are displaced relative to the sample the measured amplitude of the harmonic component is stored in suitable storage means as a function of location in the sample. Thus, a map of the superconducting properties of the sample may be generated.

Abstract: A target detection system is provided for examining picture signals of a scene which may contain a target signal (15,16) to be detected against background signals (17,18). The image is divided into sub-images and sub-stores are provided one each for the sub-images (19). The values of a set of features, such as brightness, volume or quietness, of the background and target picture signals associated with each sub-image in the respective sub-store are calculated and stored. The statistical distributions of the background and target features in each sub-store to set a target decision threshold, in feature terms, for each sub-image are calculated. The feature values of an incoming picture signal in a sub-image are compared with the decision threshold in the associated sub-store to provide a target detection signal. Each sub-image threshold relates to the image status in that particular sub-image. A lower false alarm rate with a higher detection probability is provided.

Abstract: The invention relates to a method of forming images of layers of an object, and a device for performing this method. The layer images are formed from single-shadow images produced from different radiation source positions. The image values of the single-shadow images are first stored in a first as well as in a second memory. From the values of given image points in the second memory, a layer image value is calculated. The layer image value is added to the corresponding image points in a third memory. From the differences between these standardized sums in the third memory and the original image values in the first memory, there are formed correction values for correcting the image values in the second memory. Improved layer images are thus obtained.

Abstract: Inert non-magnetic metals are adhesively bonded to surfaces of metal oxides, for example ferrites, by means of a water vapor-hydrogen atmosphere. Reduction of the metal oxide only takes place at the interface of the inert metal and the metal oxide, after which the metal formed is partly dissolved in the inert metal.

Abstract: A method of modulating an optical beam (1) and apparatus for use in such a method are described. An etalon structure (2) is provided which has an absorption edge in the vicinity of the wavelength of the optical beam (1) and which comprises material of a smaller band gap, for example gallium arsenide, sandwiched between layers of material of a larger band gap, for example aluminium gallium arsenide, so that the smaller band gap material forms a quantum size effect confinement region for electrons and holes. The smaller band gap material may consist of layers (4) separated by barrier layers (3) of the larger band gap material so that the layers (4) form quantum wells.

Abstract: The bifocal optical system is formed in the long focal length mode by an objective having fixed lenses L1, L2, L3, L4 to which, for obtaining the short focal length, a group of movable lenses L5, L6, L7, L8 is added. The lenses L5, L6, L7 and L8 are accommodated in a holder (MB) which is rotatable around an axis YY' which extends parallel to the optical axis XX', thereby enabling very wide tolerances in the positioning of the movable holder.

Abstract: The arrangement (201) comprises an optical narrow detection beam (203) focussing system for a passive infrared radiation in accordance with a reference plane (U). A filter selects the spectral analysis band and at least one passive infrared radiation detector is provided in the focal plane. According to the invention, the arrangement comprises a first analog processing chain and a second digital processing chain by means of which it is possible to recover in accordance with a characteristic curve at least the undercarriage of vehicles. On this curve, each turning element of the undercarriage assumes the shape of an identifiable pulse. The arrangement is used in the identification of moving vehicles in a predetermined plane.

Abstract: A device chamber (12) is evacuated by pumping via an evacuation tube (35) to produce a vacuum space in communication with a chemically-active getter (30) which is provided in the tube (35) to getter gases from the evacuated chamber (12). In accordance with the invention, the getter (30) in the form of one or more movable bodies of the getter material is activated by heating in the evacuation tube (35) at a safe location (36) distant from the chamber (12). It is then moved towards the chamber (12) and is retained in the sealed evacuation-tube outlet (31) of the device. A vacuum-permeable screen (12) in the evacuation-tube outlet (31) inhibits passage of the getter material (30) into the chamber (12) where it might, for example, otherwise damage or obscure an infrared detector element.

Abstract: The entrance screen in an X-ray image intensifier includes an intermediate layer of a material which selectively absorbs photon energy. As a result, the speed of the photo-electrons is substantially reduced, thus improving the imaging. By introducing a radial variation of the absorption in the intermediate layer, vignetting-compensation can also be realized without substantial loss of sensitivity and resolution for the central portion of the tube. The resolution at the periphery of the tube can thus be substantially improved.

Abstract: Apparatus and methodology for the rapid and inexpensive characterization of superconducting materials. The method and apparatus induces an alternating magnetic field in the sample to be tested. If the material is a superconductor odd harmonics are generated in the alternating magnetic response of the material near the transition temperature. The superconducting transitions are manifested by a peak or peaks in the odd harmonic components of the alternating magnetic response as a function of temperature. The peaks of the harmonic components are detected to indicate the presence and number of superconducting transitions.

Abstract: A laser diode module comprises a rectangular, box-like metal casing having a bottom (B), whereas an even number of guide pins (1-14) are passed through the bottom (B) in a standardized DIL order and no less than one guide pin (5) is electroconductively connected to the bottom (B). In addition to the laser diode (LD) itself the module further includes a Peltier cooler (TEC) and a thermal metal base carrier (BC) coupled thereto, which base carrier accommodates the laser diode (LD), a photodiode (PD), a support (S) for the glass fibre (F) and a thermistor (TH). In order to render this laser diode module suitable for use in communication systems with bit rates that exceed by far 1 Gbit/s, the said guide pin (5) has inside the casing a portion in the form of a rod with a constant cross-section and with no less than one flat side face which over its entire surface has an electroconductive coupling with the relevant long sidewall (SW.sub.

Abstract: An actively phase matched waveguide structure suitable for use as a frequency doubling device is described. The device includes a non-linear optical waveguide and phase matching of the waveguide is controlled by an electrically operated light modulator which is spaced apart from the waveguide. The modulator includes one or more electrodes disposed on a substrate and an elastomeric transparent gel which has a metallic coating on its upper surface. Application of a voltage between the metallic upper surface and the electrodes causes a deformation in the gel which alters the gap between the upper surface of gel and thus provides phase matching.

Abstract: The method has for its object to enhance the contrast of an image, more specifically a low-contrast infrared image. The method is used in a system for putting the method into effect, more specifically an infrared camera operating in real time. The output image is structured with the aid of a transformation function (FI) one part of which (RCI) transforms the contrast of the warm points; the output histogram (HSI) has a higher contrast than the input histogram (HE). The point GO is determined for each image as a function of the characteristics of the input histogram (HE).

Abstract: A photomultiplier tube (10) for the use in high collecting power is described having a photocathode (20), a first dynode (30) and a stackable-dynode multiplier device (40). According to the invention, the first dynode (30) is constituted by a sheet which extends parallel to the photocathode (20) and is provided with a feedthrough aperture (31), an extracting grid (32) being arranged between the photocathode (20) and the sheet, and the stackable-dynode multiplier device (40) is positioned opposite the aperture (30) in such a manner as to collect the secondary electrons (50) emitted by the first dynode (30) and passing through the feedthrough aperture (31).

Abstract: A picture analyser tube with streak compensation constituted by a light intensifier tube structure comprising a photocathode (1) associated with an acceleration grid (2) and a microchannel plate (3) associated with an acceleration grid (4) coupled to an electron-sensitive (6) or photosensitive objects (7) CCD matrix. The wire compensation effect is obtained, for example, by deflecting the electron beam issued by the photocathode (1) by means of electromagnetic coils (5) traversed by currents the intensities of which are controlled in order that the deflection movement of the said beam is opposite to the movement of the picture during the duration of the passage of the object in the field of view of the device. The picture is thus immobilized in the plane of the CCD detector.

Abstract: A camera for recording television, photographic or cinematographic images includes an automatic focus-setting device. Information for this device is obtained with the aid of two optical paths having different path lengths present in an optical lens system placed in front of an opto-electronic sensor in the form of a charge transfer device comprising a pick-up member, a storage member and a shift register member. After a signal comparison of signals obtained during focus information recording periods the focus is set until an optimum signal correlation is the result.