Abstract: In a pulsed gas laser, pulses of electrical or other energy are desirably converted in part into pulses of quantum mechanical pumping of the lasable gas, and unavoidably converted in part into pulses of heating of the lasable gas. According to this invention, efficiency and economy of operation are enhanced by exploiting the pulses of heating to propel and recirculate the gas through cooling means to freshen it thermally for further cycles of lasing, utilizing a structure comprising an acoustically tuned duct and an acoustic diode to establish proper phasing and direction of the pulsed and recirculating operation. The invention, although applicable to other gas lasers, is particularly applicable to electron beam ionized, electrical current sustained lasers. The invention reduces if not eliminates the cost, bulk and other disadvantages of a mechanical pump or other conventional recirculation equipment.

Abstract: A high pressure, high power, continuous wave electro-dynamic laser having one of the electrodes (preferably the cathode) made of a porous conductive surface and a backing material capable of broad band acoustic absorption. Such an arrangement effectively absorbs acoustic disturbances which arises primarily from a linear instability within the resonant cavity of the electro-dynamic laser and thereby substantially reduces output flux modulations within the resonant cavity.

Abstract: A laser mirror adapted to prevent astigmatism of reflected laser beams where the mirror is used for "folding" the laser beam such that the incident laser beam direction is not normal to the reflective surface of the mirror. This is accomplished by the provision of slots of specified dimensions in the rear surface of the mirror that in use are disposed parallel to the major axis of the laser beam's image on the mirror. In this manner, the mirror is provided with two bending stiffnesses, one in the direction of the major axis that is greater than that in the direction of the minor axis such that the bending due to heating of the mirror in the direction of both axes is made at least substantially equal.

Abstract: Herein described is an unstable resonator optical cavity for lasers which may have a square, rectangular or the like spherical concave primary reflection surface at one end of the cavity that intercepts the optical axis of the cavity at or adjacent to one of its corners and a more or less similar square, rectangular or the like spherical convex feedback reflection surface at the opposite end of the optical cavity that intercepts the optical axis at or adjacent to one of its corners arranged and adapted to define an unstable resonator cavity.

Abstract: A method of producing a lasable gaseous mixture for use in and operation of electron beam-sustainer carbon dioxide lasers comprising burning a hydrocarbon fuel to produce substantially oxygen free products of combustion, removing undesirable constituents to leave a gaseous mixture which can support laser oscillation comprising substantially only carbon dioxide, nitrogen and hydrogen, collecting the resulting gaseous mixture, and thereafter supply and use it as the active medium in an electron beam-sustainer laser.

Abstract: Working gas for an electron beam discharge laser is generated by an airbreathing, hydrocarbon fuel burning, turbocompressor engine and shaft power of the engine may be utilized to drive a generator to provide electric power to the laser or to drive a compressor to put the turbocompressor exhaust gases in compressed storage for later use in the laser, either mode affording savings in weight and cost of operating materials and/or specific energy conversion efficiency compared to prior art, electric, chemical and gas dynamic laser systems.