Abstract: A gasdynamic CO.sub.2 -laser in which the lasing medium is being cooled by expansion in a Laval nozzle, is operated in a way to amplify the cooling effect. This increased cooling is accomplished by introducing liquid droplets into the expanding lasing medium. These droplets are entrained by the flowing medium whereby the droplets are taken along with a speed corresponding approximately to the speed of the expanding lasing medium. The amplification of the cooling is accomplished by the evaporation of these droplets.

Abstract: In a gasdynamic laser in which the hot flowing lasing medium (e.g. CO.sub.2 --N.sub.2) is cooled by expansion in a Laval nozzle 1, liquid droplets are introduced into the expanding lasing medium to increase the cooling effect. The liquid can be water, preferably heavy water, from a container 4 pressurized by the laser medium in plenum 6 and introduced from pipes 3 into a region immediately before the nozzle neck 2 so as to be atomized and accelerated through the neck 2. Evaporation occurs downstream of the neck and causes an increase in the cooling. The droplets preferably have a size in the range 1-20 .mu.m and may contain dissolved CO.sub.2. The droplets may be dispersed in a super cooled gas which is then injected into the lasing medium.

Abstract: Uniform, transverse electrical discharges are produced in gaseous media without the necessity of switching the main discharge voltage with an external device which carries the entire discharge current. A three-electrode low pressure discharge tube is charged across its anode (1) and cathode (2) to below breakdown voltage using a dc voltage source (3). An array of resistors (4) or capacitors can be made to discharge to the wire screen anode by means of a low energy high voltage pulse circuit (5) producing sufficient preionization in the region between the anode and cathode to initiate and control the main discharge. The invention has been demonstrated to be useful as a CO.sub.2 laser oscillator and pulse-smoother. It can be reliably operated in the sealed-off mode.

Abstract: A hypersonic wedge nozzle for chemical lasers that has a radially diverging low primary nozzle with a multiplicity of hypersonic wedge type secondary injection wedges at the exit end of the primary nozzle to allow gas flow to become supersonic in the primary nozzle before entering the regions between the secondary injection wedges or the surfaces thereof. Utilization of the large diverging primary nozzle in producing supersonic flow minimizes viscous effects in producing the supersonic flow in a chemical HF or DF laser.

Abstract: A method and apparatus for visually analyzing gaseous flow fields. A vaporous substance that fluoresces when irradiated by a particular laser beam is injected into a structure containing a flowing gas in a manner such that a uniform dispersion of the vaporous substance throughout the gas flow is achieved. The beam from a pump laser in optical communication with the gas flow pumps the ground state of the vaporous substance to an excited state and causes the vaporous substance to fluoresce in the area illuminated by the beam, thus providing a visual indication of the pattern of gas flow in the structure.

Abstract: In a coaxial type gas-flow laser device in which a laser beam axis, an electric discharge axis and a gas flow axis are coincident, at least one centrifugal blower is employed for circulating a laser gas. Where two centrifugal blowers are employed, they oppose to each other in an axial direction of discharge tubes.

Abstract: A primary nozzle provides a two-dimensionally expanding source flow of an oxidizer; a line serving as origin; and curved secondary nozzles are positioned in the primary, supersonic flow, for discharging fuel in radial direction, parallel to the oxidizer flow, mixing therewith in the laser cavity. The secondary nozzles have concavely curved, leading edges as well as concavely curved expansion edges downstream from the leading edges, positioned to cancel shockwaves from the leading edges of the respective adjacent secondary nozzles. The secondary nozzle structure provides a radially expanding fuel flow and maintains the radially expanding primary flows shock free. This radially expanding, primary flow accommodates the unused heat of reaction so that pressure is maintained nearly constant in the laser cavity. Supersonic expansion provides a low, initial pressure, and the radially expanding flow thereby maintains this pressure low.

Abstract: A high power metallic halide laser capable of providing 300 watts of output power. More specifically, a laser amplification system is disclosed whereby a metallic halide vapor such as copper chloride (Cu.sub.3 Cl.sub.3) is caused to flow through a laser amplifier (10) and a heat exchanger means (24) in a closed loop system whereby the flow rate is altered to control the temperature rise across the length of the laser amplifier. In the copper chloride laser described in an exemplary embodiment, the copper atoms within the laser amplifier should not exceed a temperature of 3000.degree. K. so that the number of copper atoms in the metastable state will not be high enough to prevent amplification in the amplifier. In addition, a molecular dissociation apparatus (20) is provided at the input to the laser amplifier for dissociating the copper chloride into copper atoms and ions and chlorine atoms and ions.

Abstract: A cw chemical laser which uses processed radioactive waste to produce act atoms from a chemically inactive gas before being mixed with another molecule such as hydrogen or deuterium is disclosed. This laser uses no toxic or corrosive fuels and does not require any electrical or other type of auxiliary power supply. The energy released by the radioactive material is used to produce the active atoms such as fluorine. This is accomplished by using the radiation products from processed radioactive waste to dissociate the inert gas in the plenum of the laser. The radioactive material is held in the passageway walls of a device similar to a heat exchanger. The exchanger device may be located in the gas generator section of a chemical laser. The inactive gas is passed through the exchanger device and while passing through it the radiation from the radioactive material dissociates the gas, producing a concentration of free active atoms.

Abstract: A dithered ring laser gyro in which the effects of mode locking, or frequency locking, at low rotation rates are reduced by producing an oscillatory flow of the ionized gas in the gain section of the laser. The envelope in which the laser is sealed includes a pair of closed-end bellows. The bellows are extended and retracted in push-pull to pump the gas. There is thus created a dynamically varying pressure differential and oscillatory gas flow along the bore of the gain section of the laser which induces a corresponding oscillatory bias in the gyro output.

Abstract: The working parts of a flowing gas laser are enclosed within an airtight housing comprising a first plenum separated from a second plenum. Blower means comprising one or more modules is provided with gas inlet means for receiving gaseous lasing medium from the second plenum and gas outlet means for exhausting the lasing medium to the first plenum. Means defining a lasing region are provided with gas inlet means for receiving lasing medium from the first plenum and gas outlet means for exhausting the lasing medium to the second plenum. The blower means provides a differential pressure across the lasing region sufficient to provide the desired flow of lasing medium through the lasing region. Due to the action of the blower means, lasing medium is caused to circulate from it to and through the lasing region and back to and through the blower means.

Abstract: A method and apparatus for providing a self-compressing supersonic flow is provided by use of a contoured supersonic nozzle design. The shape of the supersonic nozzle array can be composed of curved blades which provide a focusing effect for a supersonic flow which will provide a gradient change in mach number along the supersonic flow path and efficient pressure recovery. Ideal design permits the self-compressing flow to have a secondary throat with down stream mach number of approximately one. As a result, a gas dynamic laser will have a well defined lasing region shortly after the increase in velocity of the working fluid to supersonic speeds. Controlled shaping of the supersonic flow is provided by means which will either use high speed jets or the Coanda effect. Further refining of the shape of the flow can permit the lasing region to take on the shape of a torus.

Abstract: An electrical discharge occurs between the anode and the cathode and the active gas such as CO.sub.2 between the two electrodes is excited to provide a laser beam. The laser beam thus provided is reflected repeatedly by a pair of reflection mirrors. The reflected laser beam is amplified while passing through the space where the discharge occurs, thus providing the function of a gas laser oscillator. Although the amplification that occurs in the discharge zone between the electrodes, considerable laser beam absorption takes place in the space between the reflection mirrors and the electrodes. In this space, the amount of operating gas such as CO.sub.2 is reduced, or the space is evacuated. Alternatively, the space is cooled by causing the gas therein to flow. A reduction in so-called laser beam absorption function is provided.