Abstract: The object of the invention is an automatic servo-controlled valve with high speed opening wherein the shutter is a hinged cover (20). Suitable locking means (30, 50) keep the cover (20) in a locked position up to the time when the pressure difference on the two faces of the cover exceeds a pre-determined minimum level. After the said locking means have moved to an open position, an actuator (40) operates the opening of the said cover at high speed (FIG. 1).

Abstract: An apodizing filter is disclosed comprising two solid bodies of transparent material the first of which is struck by the incident light while the second receives the light from the first. The second body has a curve surface approaching the first body at a distance therefrom not greater than some wavelengths of the incident light. The plane tangent to the curve surface of the second body at the point of minimum distance from the first one forms with the direction of the incident light an angle greater than the limit angle of the total reflection related to the first body with respect to the medium in which the filter is sunk. The indexes of refraction of the two materials of which the two bodies are made are such that the light incidence on said tangent plane is lower than the limit angle of the total reflection. The combination is disclosed of the apoditic filter according to this invention with a mirror and an example is given of the filter application to a laser cavity.

Abstract: In order of maintaining at the more constant level the CO.sub.2 content in the gaseous mixture discharge of a transversely excited atmospheric pressure laser, a polymer product is included in advance of the laser operation in the laser chamber or within the closed fluidtight circuit where the gaseous mixture is recycled. Such polymer is produced by irradiating tripropylamine with ultraviolet photons and/or with energy electrons in the form of a layer whereby at least a portion of a solid support is coated.