Abstract: The present invention provides a powder coating composition obtainable by homogeneous mixing of at least two separately produced powder coating compositions as powder coating bases, especially suitable for the coil coating technology, that means, for coating applications also under high speed, e.g., at coating speeds of about >50 m/min providing coatings with a high flexibility for post forming. In spite of substitution of TGIC, the powder coating composition of this invention are coating compositions having a good storage stability and giving coatings with any desired gloss level as well as good coating properties, particularly, high exterior durability and stable flexibility and the compositions are suitable for the coil coating technology, that means, for coating applications also under high speed.

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: A method of controlling a unipolar semiconductor laser in the 4-12 &mgr;m mid-infrared range. This is an optical control method, unlike a purely electrical, power control method which injects a relatively large flux of electrons. The optical control method may advantageously include two optical beams of the same wavelength and a device for making those beams interfere in the active layer of the laser, the optical control beams having a much shorter wavelength than the wavelength of the unipolar laser and having a frequency capable of being modulated more rapidly than that of the laser.

Abstract: This semiconductor laser comprises at least two layers of optically non-linear material as well as a quantum well at least located within one of the layers of optically non-linear material. The thicknesses and optical indices of these two layers are such that the waveguide constituted by these two layers has a modal phase matching condition for the process of parametrical fluorescence between the pump wave emitted by the quantum well and the parametrical conversion waves.

Abstract: A unipolar multiple-wavelength quantum well laser comprises at least two stacks of layers of semiconductor materials. Each stack forms a quantum well laser working by intra-band transition and emitting a specified wavelength. The two stacks of layers are separated by a stack of layers of semiconductor materials constituting a quantum well transfer lattice which, under an electrical field, enables a transfer of electrons from the low level of the (conduction or valence) band of a quantum well of a first laser to the high level of the (conduction or valence) band of the quantum well of a second laser. FIG. 2b.

Abstract: A detector with quantum structure comprising a small-gap semiconductor material inserted between two large-gap semiconductor materials, the structure comprising a coupling grating between the wave to be detected and the detector zone constituted by the small-gap material. Under these conditions, the detector zone may have a very small thickness (typically of the order of 1,000 .ANG.) and lead to a detectivity, limited by the dark current, that is high.

Abstract: A frequency converter can be used, in particular, to generate optical waves in the medium infrared (3.12 .mu.m) range from optical sources in the near infrared range. It comprises a heterostructure semiconductor waveguide formed by an alternation of layers of material M.sub.I and M.sub.II, at least one of these materials being a non-linear semiconductor and the plane of the layers being parallel to the direction of propagation of the electromagnetic waves in the waveguide.

Abstract: Disclosed is a semiconductor laser that is constituted by at least one active layer sandwiched between two confinement layers with P and N type doping to constitute a PN junction. In at least one of the confinement layers and/or the active layer, holes are designed on each side of the cavity so as to form structures of photonic bandgap material along the lateral walls of the cavity and the ends of the cavity.