Abstract: An improved system and method are provided for removing material coatings or contaminants such as paints from a structure. The system and method include a radiant energy source, such as a flashlamp, for irradiating the target area of the structure with the radiant energy sufficient to initiate the pyrolysis and/or ablation of the coating or contaminant and a low temperature carbon dioxide stream which is directed at the target area to disperse the material from the structure, clean the exposed surface and cool the underlying substrate. The low temperature carbon dioxide stream is formed from a liquid carbon dioxide from a liquid carbon dioxide source which undergoes phase transition to yield a predetermined amount of low temperature carbon dioxide gas and carbon dioxide snow. The system and method eliminate the need for a carbon dioxide pelletizer, a carbon dioxide pellet transport hopper, and a compressed carrier gas which are used in related systems.

Abstract: A pulsed or CW laser is rapidly switched to operate at one or more selectable wavelengths by means of intracavity insertion of beam dispersion and focussing elements and an apertured focal plane mask and shutter assembly. The laser beam has an axis and is dispersed into components or sub-beams having different axes and representing different wavelengths, the sub-beams being focussed to substantially reduced diameters on the focal plane mask at points, respectively, at which apertures are formed. Movable shutters adjacent to the respective apertures control alternate opening of and closing of the apertures and selectively permit the laser to resonate at at least one of a plurality of wavelengths corresponding to that of the sub-beam passing through an open aperture. Mask apertures having very small diameters (<50 microns) and separations are achieved enabling switching between different operating wavelengths in milliseconds.

Abstract: A laser electrode assembly comprises an elongated bar having a plurality of longitudinally spaced sockets and is removably secured to a carrier which is anchored to the laser base and has a like number of plugs resiliently press-fitted within the sockets, respectively. Each plug has opposed sides to which are fastened a plurality of outwardly curved resilient fingers extending parallel to the direction of insertion of the plugs into the sockets. Each socket has a width less than the overall width of the plug and finger combination so that the fingers resiliently frictionally engage the bar within each socket. The bar is readily removed from the carrier for maintenance and repair purposes by prying the former from the plugs without necessitating removal of screws or bolts and thereafter passing the bar through the window opening aligned with the discharge gap.

Abstract: A pulsed electric discharge gas laser driven by a folded Blumlein transmission line with liquid dielectric. A method of preionizing and firing the laser discharge utilizing the Blumlein voltage pre-pulse for preionization and the subsequent main voltage pulse for gap switch breakdown. A spark gap switch construction with first and second elongate electrodes, with the first electrode presenting a generally rounded surface to the second electrode which incorporates a thin continuous edge facing the first electrode. An elongate apertured cathode at the lasing chamber, with an elongate preionization electrode positioned behind the cathode, and a power supply providing a preionization electrical pulse across the cathode and preionization electrode producing ions and electrons in the lasing gas prior to the main discharge between the anode and cathode.