Abstract: The apparatus incorporates a h.f. source (2), a plasma enclosure ( 4 ) having gas supplies, a vacuum pump (50), elements for coupling the source to the plasma enclosure, which is of a non-radiating type and which is shaped like a rectangular parallelepiped with first and second dielectric material faces parallel to the direction of the magnetic field and a third face having a rectangular opening (14) parallel to said field for forming a ribbon-like plasma, a treatment enclosure containing a mobile sample holder (18) communicating via the opening with the plasma enclosure. The coupling means have two linear waveguides (30, 38 ) with a rectangular cross-section oriented in the wave propagation direction and located on either side of the plasma enclosure, a horn (36) for coupling one of the guides to the plasma enclosure, whose cross-section widens in the magnetic field direction, the other guide being provided with a short-circuit (46).

Abstract: A plasma reactor, of the type comprising an enclosure capable of receiving a gas flow, a generator of high-frequency electromagnetic waves and means for the non-resonant coupling of the generator with the enclosure, the coupling means including at least one horn with widening having an essentially rectangular cross-section, with its two walls perpendicular to the direction of the electrical field moving away angularly from each other, the two walls parallel to the direction of the electrical field remaining substantially parallel. Preferably, the reactor includes a horn with widening and a horn with narrowing parallel to the direction of the electrical field, placed essentially in succession in coupling means. The invention thus makes it possible to obtain large-sized plasmas of any shapes with high homogeneity.

Abstract: The invention relates to a plasma reactor including a housing which receives a selected gas flow, a microwave generator, and waveguide means to supply the microwaves to the housing according to a non-resonant coupling wherein the housing does not dissipate in the form of electromagnetic radition the ultrahigh frequence energy which is imparted to the housing in the presence of gas. According to a general definition of the invention, the housing being of a large size, the terminal portion of the waveguide means is progressively reduced in one direction and widened in the other direction till it reaches a flat rectangular cross-section surrounding completely the housing, and it forms a non-resonant coupling with the housing.

Abstract: It realizes the chemical vapour phase deposition method using a plasma maintained by surface waves in a tube (2) for obtaining a preform and comprises photodetection means (50) sensitive to the light emitted by the deposition area (54) of the vitreous coating resulting from the reaction between appropriate gaseous compounds and able to supply information relative to the emission area of said light, and means (52) for controlling the displacement of the deposition area, displacement being such that the thickness of the coating is uniform in the tube, and control means controlling the power of the microwave generator (30) of the apparatus as a function of the information. Application to the field of telecommunications.

Abstract: A waveguide (130) is coupled to a tubular member (2) by a gap (139) suitable for generating an intense surface wave in a gaseous mixture contained in the tubular member (2). Short circuits (110 and 120) delimit the plasma, thereby generating very high intensity standing microwaves, which increase the energy density of the plasma. An ion laser effect can then be observed, in particular in a mixture of argon and helium, together with optional krypton.