Abstract: A generator of a TE.sub.O mode wave beam, particularly adapted for confining plasmas, comprises a laser device for generating an electromagnetic wave having at least a TM.sub.O mode component. The TM.sub.O mode component is filtered by parallel sided plates or refractive surfaces disposed at the Brewster angle for the TM.sub.O component to derive an intermediate wave beam. A TM.sub.O -TE.sub.O mode converter shifts the TM.sub.O mode intermediate wave polarization vector by an angle of .pi./2 radians.

Abstract: Generator and power amplifier of plasma confining, electromagnetic, light or infrared wave beam. It comprises a generator of a rectilinear polarized wave beam and a solid state laser beam amplifier amplifying the rectilinear polarized wave beam after conversion of the same and having a doped active material in the shape of an annular sleeve member. This amplifier operates in the TM.sub.o annular mode. It is preceded and followed by mode converters. The first mode converter before the amplifier converts the rectilinear polarized wave beam to a TM.sub.o mode wave beam and the second mode converter after the amplifier converts the amplified TM.sub.o wave beam to a negatively azimuthally phase shifted, circular polarized wave beam.

Abstract: Laser device emitting a far infrared wave beam having a mode confining for charged particles. The laser devices of this kind generally emit circular polarized wave beams in which the phase shift of the radioelectric oscillation at a point having a given azimuth with respect to the beam axis is proportional to the azimuth. They comprise a quarter wave plate for converting a linear-polarized wave to a circular polarized wave and a non-confining to confining mode converter. The known converters use birefringent materials but there is no birefringent material available in the far infrared range. The present non-confining to confining mode converter uses dielectric parallel sided plates having a metal coated face forming a mirror.

Abstract: Guide for light or infrared wave beam in which a radial temperature gradient deflects towards the guide axis the light rays which tend to diverge therefrom. The isotherm pattern of two sets of four heater wires, each set being formed of pairs of wires diametrically opposite with respect to the guide axis, is calculated and it is shown that it comprises a particular isothermic curve which has the shape of a bean and separates the two sets of wires. The metal wall of the guide is given the shape of this particular isothermic curve and the set of heater wires outside this wall is omitted.

Abstract: Mode converter for electromagnetic, light or infrared waves. This mode converter converts particle non-confining modes to particle confining modes. In a confining mode wave beam the phase of the wave with respect to time at a point of the beam having a given azimuth with respect to the beam axis is proportional to this azimuth. Two types of mode converter are disclosed. In the first type, the wave passes through a block of transparent isotropic material the thickness of which is proportional to the azimuth around the beam axis. In the second type, the converter is formed with triangular or sectoral plates of birefringent material and in each plate the slow and fast axes are given an adequate orientation.

Abstract: A ring laser for penetrating electromagnetic radiation such as X or gamma rays, using a pumping beam supplied by a primary lightwave or infrared laser. A member made of active material is illuminated by the beam, which has symmetry of revolution around its axis and whose electric lines of force are circles centered on the said axis. The pumping beam is conveyed by a mirror toward the end of a circular metal channel having a semi-toroidal cross-section and containing the active member, the mirror being formed with an aperture near the axis and transmitting the X or gamma rays emitted by the active member after they have been propagated along the end of the channel. The active member may be made of a substance which can undergo thermonuclear fusion by absorbing X or gamma rays. The active substance may also be a boron hydride or a boronate.