Abstract: A dielectric material layer is formed on a carrier material. A gas mixture containing at least one precursor comprising a metallic element is alternately circulated with an oxidant gas in contact with the carrier material under first oxidizing conditions so as to form a first sub-layer having dielectric qualities. A gas mixture containing the same precursor then is circulated in contact with the first sub-layer under second oxidizing conditions being more strongly oxidizing than the first oxidizing conditions so as to form a second sub-layer having dielectric qualities.

Abstract: A laser cavity with passive switching by a saturable absorber and a laser incorporating the cavity. The laser cavity has a solid, active material saturable absorber, an entrance mirror and an exit mirror. The saturable absorber is a thin film of saturable absorber material directly deposited on the solid, active medium. The laser incorporates such cavity and a mechanism for pumping the cavity.

Abstract: Mixed silicates of yttrium and lanthanide and laser using monocrystals of these silicates. The laser has a laser cavity (2) containing as the light emitter a monocrystal (4), means (12,14) for amplifying the light from the monocrystal, means (14) for removing light from the laser cavity and optical pumping means (6), characterized in that the monocrystal is of formula (I):Y.sub.2-2x-2y M.sub.2x Yb.sub.2y SiO.sub.5 (I)in which M represents a lanthanide chosen from among erbium and thulium and x and y represent numbers such that 0<x.ltoreq.0.2 and 0<y.ltoreq.0.2.

Abstract: The invention relates to monocrystals of silicates of lanthanides usable as scintillators for the detection of X and/or gamma radiation.The lanthanide silicate complies with formula:(Ln.sub.1-x.sbsb.1.sub.-x.sbsb.2.sub.-x.sbsb.3 Ln'.sub.x.sbsb.1 Ce.sub.x.sbsb.2 Tb.sub.x.sbsb.3).sub.9.33 (SiO.sub.4).sub.6 O.sub.2in which Ln and Ln', which differ, represent a rare earth element chosen from among La, Gd, Yb and Lu and x.sub.1, x.sub.2 and x.sub.3 are such that0.ltoreq.x.sub.1 <10.ltoreq.x.sub.2 .ltoreq.0.050.ltoreq.x.sub.3 .ltoreq.0.050<x.sub.2 +x.sub.3 .ltoreq.0.10<x.sub.1 +x.sub.2 +x.sub.

Abstract: These lasers in particular have two flashlamps (30, 32) for longitudinally pumping a monocrystalline aluminate bar (28) emitting in the visible and near infrared, two mirrors (38, 40) for amplifying the light emitted by the bath, a polarizer prism (42) used for feeding the amplified light beam to the outside of the laser cavity. The magnetoplumbite-type aluminate has in particular the formula:La.sub.1-x Mg.sub.1-y-z Mt.sub.v Al.sub.11+x+2y/ 3-v O.sub.19-z(II)in which Mt represents a transition metal chosen from titanium and zirconium; x is a number such that 0<x<0.3; y and z are numbers such that 0.ltoreq.y+z.ltoreq.1 with 0.ltoreq.y.ltoreq.1 and 0.ltoreq.z.ltoreq.1; v is a number such that 0<v<1.

Abstract: An infrared radiation reflecting substrate, having deposited thereon a first layer formed from a metal or an alloy, and a second layer deposited on the first layer and consisting of a solar radiation absorbing amorphous material, such as amorphous carbon. The substrate can be formed from an infrared radiation reflecting layer deposited on a primary substrate.