Abstract: A pressure-wave cycled, repetitively pulsed gas laser comprises a laser cavity having open first and second ends, a channel connecting the first and second sides of laser cavity and a lasing initiation mechanism including two electric discharge electrodes. The electrode discharge generates a shockwave and associated pressure ridge. The channel may be a conicoidical channel of which the first and second open sides of the laser cavity form, respectively, large and small entrances for the shock wave and pressure ridge whereby when the wavefronts meet in the channel the energy thereof cancels in proportion to the entry areas and the resultant wave proceeds to the small entrance where it is accelerated by the nozzle action of the small entrance, entrains non-disassociated gases and circulates the gases through the laser cavity.

Abstract: A carbon dioxide laser oscillator comprises a discharge tube, total reflecting mirrors and partially reflecting mirrors arranged at opposite ends of the discharge tube, a pair of electrodes for causing electrical discharge to occur in the discharge tube and means for flowing laser gas through the discharge tube so that the gas flows at a rate that satisfies the condition in which the Reynolds number is equal to or smaller than 1.times.10.sup.4.

Abstract: A transverse flow gas transport laser including a closed loop of ducting through which a gaseous lasing medium can be circulated so as to pass continuously through a lasing region of the ducting in which it can be excited into lasing activity, in which there is included means for extracting a portion of the gaseous lasing medium from a region of the ducting other than the lasing region, comprising the said portion of the lasing medium and injecting it back into the remainder of the lasing medium thereby to induce flow of the gaseous medium through the lasing region of the ducting.

Abstract: An improved gas laser is disclosed. The laser has a support tube to support and to maintain the alignment of the optical resonator structure. The gas lasing medium is used within the support tube to maintain the tube at a substantially constant temperature above the ambient. Furthermore, an active temperature controller is disclosed. The temperature controller maintains the gas lasing medium in the support tube at a substantially constant temperature. An active pressure controller is also disclosed. The active pressure controller uses a pressure sensor, an electronic processor, and a motor-driven needle valve to maintain the pressure of the gas lasing medium in the laser within the desired operating pressure range. The laser can also be switched in operation from a continuous mode to a pulsing mode. An active power control system is disclosed wherein the power output of the laser, through an active feedback loop is maintained at the desired level.

Abstract: A sealed-off CO.sub.2 laser employs a catalyst to promote the recombination of CO and oxygen. The catalyst is loosely contained within a catalyst holder having a plurality of apertures and the catalyst is brought into contact with the gas by means of the pressure pulse caused by the electric discharge.

Abstract: A waste management system for a DF or HF chemical laser or certain other types of chemical lasers wherein the exhaust gases of the laser are fed into a reaction chamber 12 having a collection sump region 14 at the bottom. A Supply tank 16 is loaded with lithium and is coupled to the chamber 12 by a valved feed line 18. Heating means 44 maintains the lithium in a liquid state. Pressurization means 40 pumps the lithium through the feed line 18 into an injector 32 which delivers the lithium to the chamber 12 where the lithium reacts with the exhaust gases. The reaction forms solid and/or liquid waste products which are collected in the sump region 14. After the laser is shut off, the pressure means 40 coupled to the supply tank 16 is replaced by a vacuum pump 44 which acts through a return line 20 coupling the tank 16 to the sump region 14. The waste products are drawn out of the chamber 12 into the tank 16, the tank lines 18 and 20 are disjoined, and the tank 16 is emptied.

Abstract: A transverse flow CW atomic iodine laser system uses a closed cycle fuel system to operate in a continuous mode. An elliptical pump cell having a Hg arc lamp cooled by deionized water irradiates with UV energy C.sub.3 F.sub.7 I gas to produce excited atomic iodine. A transverse flow section attached to the pump cell channels C.sub.3 F.sub.7 I gas into a laser cell where lasing occurs. The flow section has upstream and downstream flow cavities, triangular shaped, that channel the laser gas. A diffuser and flow straighteners are placed in these cavities to make the flow velocity across the transverse laser axis as uniform as possible so as to produce very stable laser gain output.

Abstract: A discharge-pumped laser with a discharge tube (1) that contains a mixture (2) of gases, that has gas inlets (4) in the vicinity of its windows (3), that has a gas outlet (7), and that is connected by lines (10, 11) and by a circulating pump (8) to a purification device that is an electrostatic filter (9) to purify the gas mixture of particles of dust without changing its composition. The gas-circulation system includes a zone (12) in which the mixture of gases being conveyed back to the gas inlets (4) becomes quiescent.

Abstract: A new Raman gain medium, comprising an optical fiber into which molecular gas has been diffused, is disclosed. This new medium combines the advantages of a fiber, i.e., long interaction path, low loss, controllable dispersion, and convenience in handling, with the large Raman wave number shift of the gas, i.e., 4136 cm.sup.-1 for H.sub.2 in silica. A laser made with such a medium can provide a relatively high power, tunable, coherent signal source in the near and far infrared regions.

Abstract: A combustion driven laser employs HBr as one of a plurality of lasing species. One embodiment of the invention lases simultaneously on the three species HF, HCl, HBr.

Abstract: A chemical laser including a laser pump which is relatively lightweight with no moving parts is provided. This produces a low pressure, regenerable, closed system for treating laser cavity exhaust gases to remove (i.e., pump) them from the system.The exhaust gases which emerge from the laser cavity of the chemical laser are pumped by a combination of condensation, cryogenic adsorption, and by reaction preferably with titanium, titanium-zirconium alloys, zirconium, tantalum, etc. These exhaust gases include hydrogen, deuterium and their halides, the halogens, oxygen, CO.sub.2, nitrogen and H.sub.2 O. This obviates the requirements for heavy equipment normally employed to produce a high vacuum in the laser cavity.

Abstract: A push-pull pulsed gas laser which utilizes piston action to displace a laser gas from the laser cavity to a heat exchanger and return of the gas to the laser cavity between laser pulses to significantly reduce the volume of gas required for repetatively pulsed gas lasers and to reduce the average power required to recondition the laser gas.

Abstract: There is disclosed continuously-excited lasers of the CO.sub.2 mixing, and supersonic CO, types. There is specifically disclosed a method, and a laser apparatus, for producing a repetitively pulsed output, in which a stream of excited gas, of the type having a relatively long excitation life, is produced, stored and subsequently transferred, in the form of pulses, to a power extraction zone incorporating a resonator. In one example the gas laser is a supersonic CO laser in which the CO is excited in the excitation zone and is, after storage, transferred under supersonic conditions to the resonator. In the main example the gas to be excited is N.sub.2 which is initially transferred to a storage chamber provided between a rotatable storage cylinder (16) and an axial supporting shaft (18) therefor, and thereafter the N.sub.

Abstract: A laser such as a wave-guide laser with its housing is encased in a second housing which is also filled with laser gas. The second housing is sealed in a gas tight manner and includes a cylindrical portion, which may be made of metal, and a cap made at least partially of glass or ceramic. The cap is provided with a neck around the laser beam passage. The neck has a rated or predetermined break strength to make sure that a portion of the cap will break off at the neck when the laser is operated. The cap is provided with a device for monitoring or checking the operation status of the laser. The checking device includes a bellows, the interior of which is connected to sense the pressure inside the second housing. Further indicators showing whether the laser is operating are also provided in the cap which breaks off automatically with the aid of the bellows when the latter expands in response to a perforation of the cap by the initial laser operation.

Abstract: A laser utilizing mercury halides as the lasing medium is disclosed. Electrodes selectively coated with a mercury gettering material are utilized to establish a glow discharge in the lasing medium. Proper ratio of mercury to bromine is maintained in the lasing medium to ensure long life operation.

Abstract: Iodine vapor is supplied to an oxygen iodine laser by an improved iodine vaporizer. The vaporizer has a radiation transparent window and iodine crystals are contained in the vaporizer. Broad beam radiation from a variable intensity source is directed through the window into the vaporizer where it is absorbed by the iodine crystals, causing the iodine crystals to sublime. The iodine vapor is transported to the laser by a carrier gas flowed through the vaporizer. Coarse control of the iodine flow is achieved by controlling the carrier gas flow. Control of the amount of iodine vapor introduced into the carrier gas flow is achieved by varying the amount of radiation directed into the vaporizer.

Abstract: In a gas laser in which a mixture of gases is excited under the influence of an electric field, a first constituent gas of the mixture is introduced into a laser tube to allow a discharge to occur in the introduced gas at predetermined partial pressure. A second constituent gas of the mixture is then introduced into the laser tube until the combined gases reach the normally operating pressure of the mixture to allow a discharge to occur in the later introduced gas.

Abstract: A flowing gas laser utilizes a multilayer gas flow technique wherein laser gas is caused to flow in three distinct layers: an anode gas flow layer flowing adjacent the anode electrode of the laser; a cathode gas flow layer flowing adjacent the cathode electrode of the laser; and a lasing gas flow layer flowing between the anode and cathode layers and through the lasing region of the laser. A higher electron density is produced in the anode and cathode layers than in the middle lasing layer for fostering a higher electric field in the lasing layer and increased electrical efficiency of the laser. The multilayer gas flow technique is also useful in chemical processing devices for generating ozone or the like.

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: A method is disclosed for manufacturing a sealed-off RF excited CO.sub.2 laser with a longer operating life. The invention, which relates to the method and the resulting laser, comprises means for stabilizing the laser gas chemistry otherwise affected by CO.sub.2 dissociation, O.sub.2 consumption, and outgassing of H.sub.2 and H.sub.2 O. More specifically, the aluminum housing of the laser assembly is nickel-plated and then passivated by an oxidation technique using concentrated nitric acid. In addition, novel gettering substances, comprising either a group B metal or cellulose, are employed to adsorb hydrogen and/or water vapor to alleviate the outgassing problem.

Abstract: A repetitively pulsed gas laser in which a system of mechanical shutters bracketing the laser cavity manipulate pressure waves resulting from residual energy in the cavity gas following a lasing event so as to draw fresh gas into the cavity and effectively pump spent gas in a dynamic closed loop.

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: A method and apparatus for convection control of metallic halide vapor density in a metallic halide laser (10). More particularly, an apparatus is disclosed wherein a reservoir (48) containing copper chloride (62), which in the exemplary embodiment is the metallic halide chosen, is heated so that the copper chloride is maintained in a liquid form. The apparatus includes a means for flowing a buffer gas, which in the exemplary embodiment is neon, over the liquid copper chloride to provide a mixture of copper chloride vapor and neon (72') above the liquid copper chloride. A conduit (50) for providing fluid communication between the reservoir (68) containing the copper chloride vapor/neon mixture and the laser (10) is also included. The copper chloride vapor density in the laser is related to the liquid copper chloride temperature and the neon flow rate through the reservoir (68).

Abstract: A gas laser adapted to produce laser radiation in the far infrared region of the electromagnetic spectrum, but adapted, as well, to produce radiation in the infrared, the near infrared, the millimeter and the microwave regions. The laser employs a zig-zag pumping scheme which serves to excite the gas uniformly and thus enhance transfer of pump energy into laser energy.

Abstract: In XeBr lasers which make use of HBr as the source of bromine, it has been found that the working life of the laser is limited because of dissociation of the HBr in the lasing region to form H.sub.2 and Br.sub.2. Accordingly, apparatus is disclosed for substantially improving the working time of the XeBr laser wherein means are provided for recombining H.sub.2 and Br.sub.2 into HBr and for continuously circulating the gaseous working medium from the lasing region through the recombination region.

Abstract: A method and apparatus is described for reducing the gas consumption rate by controlling the gas composition in a repetitively pulsed high pressure and/or high energy density TE CO.sub.2 laser. Detrimental gas species formed in the discharge are removed by chemical reaction in the gas phase and the reaction products are removed by a trap in a recirculator loop. In particular, the primary detrimental species is oxygen, the reducing gas added to remove this is hydrogen or deuterium and the resulting oxides of hydrogen or deuterium are removed by a molecular sieve.