Abstract: A novel excitation scheme has been developed for discharge lasers. The technique uses an auxiliary circuit based upon pulse transformer technology to induce a fast, high voltage pulse directly onto a ground potential laser electrode resulting in the breakdown of the laser gas mix. Saturation of the pulse transformer core inductance then permits the efficient "switching" of the main energy storage circuit into the discharge.

Abstract: A method of reducing an expenditure of a rare gas in an excimer laser system includes evacuating a lasing material including a mixture of diluent rare gas and removing therefrom halogen compounds. Supplemental lasing material is then added to the lasing mixture.

Abstract: For an excimer laser system utilizing in a laser chamber a lasing material and a mixture of a diluent rare gas and a heavy rare gas and halogen rare gas in given percentages there is disclosed a method and apparatus for reducing the expenditure of the rare gases by continuously evacuating the laser mixture from the laser chamber removing from the evacuated laser mixture any foreign halogen compounds to provide a cleaned laser mixture and thereafter feeding the cleaned lasing mixture back into the laser chamber. Along with the cleaned laser mixture there is fed in a supplementing lasing material which is a mixture of the halogen gas, the diluent gas and the heavy rare gas. The percentage of the halogen gas in the supplemental material is substantially greater than the given percentage in the lasing chamber while the percentages of the diluent gas and the heavy rare gas are substantially the same as the percentage ratios of the given percentages.

Abstract: A method is disclosed for optimizing the performance of self sustained diarge rear gas halide lasers by using a gas mixture containing two halogen bearing gases. One of these gases is chosen for its attaching properties to optimize the operation of the discharge. The other gas is chosen for its weak attachment and its ability to form the excimer molecule in collisions with rare gas metastables. A representative strongly attaching halogen donor, XHn, is selected from F.sub.2 and NF.sub.3, and a representative nonattaching halogen donor, YHn, which may be weakly attaching, is selected from CH.sub.3 F, CH.sub.2 F.sub.2, and CHF.sub.3. The XHn gas has a concentration value from approximately 0.1 percent up to about 10 percent which is adjusted to maximize the production rate for excited and positively ionized rare gas atoms to yield the excimer state molecules RgHn*, wherein Rg is a rare gas.

Abstract: Disclosed is a method of maintaining the power of the output of a xenon chloride laser. The gases in the lasing chamber are circulated between the lasing chamber and a reforming chamber. In the reforming chamber, the gases are contacted with at least one metal chloride which is chemically less stable than hydrogen chloride. The temperature of the metal chloride in the reforming chamber is maintained between the condensation temperature of hydrogen chloride and the dissociation temperature of the metal chloride used. Also disclosed is apparatus for performing this method.

Abstract: An improved electric discharge XeF excimer laser employs a reaction gas mixture containing NF.sub.3 and F.sub.2 in proportions that tailor the kinetics of the electrochemical reactions in order to achieve a substantial increase in power.

Abstract: A xenon fluoride (C.fwdarw.A) laser operating in the visible region is improved by the use of a synthesized buffer gas containing at least two components that combine to provide kinetic properties that are different from those of any single-component buffer gas.

Abstract: A preferred embodiment of an excimer laser has a heat pipe oven adapted to raise sodium therein to a temperature of about 800 Kelvin and thereby vaporize the sodium at a pressure of no more than about 0.1 atmosphere, the heat pipe oven having substantially transparent ends. A ring cavity made up of a plurality of mirrors and an adjustable birefringent filter circulates violet light of a desired wavelength through the transparent ends of the heat pipe oven, and a pump laser introduces radiation into the heat pipe oven at an energy high enough to ionize sodium therein to form Na.sub.3.sup.+ ions and free electrons. The recombination of Na.sub.3.sup.+ ions and free electrons causes the ions to dissociate into free sodium atoms and excited Na.sub.2 molecules which, when stimulated by violet light of the desired wavelength, further dissociate into two free sodium atoms and emit additional violet light of the desired wavelength.

Abstract: A high average power, high repetition rate pulsed gas transport laser system is disclosed. A pulse forming network location for minimizing electrical discharge loop inductance is provided. RFI shielding is included as a result of containment of the pulse forming network housed in a dielectric structure eccentrically mounted within a pressurizable vessel and forming a portion of a high-speed gas flow loop. The gas recirculating blower motor is mounted external to the pressurizable vessel and, therefore, does not add to the laser system dimensions. The blower is coupled to the blower motor by a magnetic coupling. Blower speed and power can be changed readily. Corona or cold-cathode X-ray preionization is provided in order to provide arc-free gas discharge. Materials compatible with the laser gases are used in construction. The laser system is configured to be compact, to be easily maintainable, and to be readily adapted for laser industrial processing.

Abstract: The efficiency of pulsed laser systems is enhanced substantially by injecting a minor amount of radiation energy into the system .DELTA.t seconds prior to the emergence of the laser pulse. The degree of power enhancement is a function of both radiation wavelength and time delay.

Abstract: An inductively stabilized, long pulse duration transverse discharge apparatus. The use of a segmented electrode where each segment is attached to an inductive element permits high energy, high efficiency, long-pulsed laser outputs to be obtained. The present apparatus has been demonstrated with rare-gas halide lasing media. Orders of magnitude increase in pulse repetition frequency are obtained in lasing devices that do not utilize gas flow.

Abstract: A condenser including a condenser chamber having an extension portion extending through the base of a refrigerant storage vessel. The length of the conduction path along this portion is variable. This may be performed by partial retraction of the extension from the vessel, or by inclusion of one or more insulating shields. Both extension and shield may be threaded. The vessel may be of thin stainless steel or compliant solid insulating material, allowing fine adjustment of the conductive path length by tightening of the shield against the base of the vessel. The internal surface of the chamber may be undulated, in particular by threading, to promote turbulent flow and mixing within the chamber. The extension may be recessed and joined to a filling tube, to facilitate initial cool down. The complete condenser is encased by expanded polyurethane foam inside a box.

Abstract: Visible and ultraviolet lasers is based on excimer transitions in the diatomic homonuclear halogen molecules. Electron beam pumping of argon and hydrogen iodide gas mixtures produces a strong green emission in I.sub.2 centered at 505 nm and a full width of half maximum (FWHM) of the gain spectrum of approximately 15 nm. The transition for the green I.sub.2 band is bound-to-free, so a laser on this transition is continuously tunable. The result is a room temperature excimer laser that is potentially tunable over a region of 150 .ANG. in the blue-green.

Abstract: Apparatus is disclosed for upconverting a laser spanning the near IR region into the near UV region. An alkali halide, for example, NaI, is photodissociated via a coherent or an incoherent pump source, for example, and ArF excimer laser or an ArF excimer flashlamp. A near IR laser, for example, a CO.sub.2 laser, is then focused into a cell containing the photodissociated Na (Na*), thereby producing anti-Stokes Raman emission in the near UV region.

Abstract: A laser device pumped by RF microwaves at frequencies in the range of 8 to 12 GHz (X-band). An optical cavity containing a lasing medium is located within an RF cavity resonant at a frequency in the X-band. X-band RF energy is supplied from an RF source to a waveguide. A coupling plate, forming a common wall between the waveguide and the RF cavity, couples the RF energy from the waveguide into the cavity to produce a standing wave pattern therein which excites the lasing medium. Various coupling plate designs are disclosed. In an alternative embodiment, a plurality of separate optical cavities containing separate lasing media are located within the RF cavity and are commonly excited by the microwave energy.

Abstract: A laser using heat and thermionic electrical output from a nuclear reactor in which heat generated by the reactor is utilized to vaporize metal lasants. Voltage output from a thermionic converter is used to create an electric discharge in the metal vapors. In one embodiment the laser vapors are excited by a discharge only. The second embodiment utilizes fission coatings on the inside of heat pipes, in which fission fragment excitation and ionization is employed in addition to a discharge. Both embodiments provide efficient laser systems that are capable of many years of operation without servicing. Metal excimers are the most efficient electronic transition lasers known with output in the visible wavelengths. Use of metal excimers, in addition to their efficiency and wavelengths, allows utilization of reactor waste heat which plagues many nuclear pumped laser concepts.

Abstract: A high power excimer laser emits a pulsed output at a high repetition rate in the ultraviolet wavelength region and a uniform power output across the laser beam. By subjecting doped silicon wafers to the pulsed laser output, epitaxial regrowth of silicon crystals can be induced to repair damage to the silicon crystal structure which normally occurs during implantation of the dopant materials.

Abstract: A crystalline array wherein selected segments thereof can be selectively energized from a primary state to a secondary state; selectively de-energized from the secondary state back to the primary state; and selectively probed to determine whether the sector selected is in the primary or secondary state. The device is capable of being utilized as a switching device.

Abstract: The disclosed molecular excimer laser discharge tube employs a transverse ectrical discharge with a UV preionization. The discharge tube is made of pure quartz with two optical quality windows fused onto the two ends. The mechanical support and electrical feedthrough for the profiled molybdenum cathodes are provided by commercially available quartz molybdenum cup seals. The anode is made of perforated molybdenum sheet and is supported by slots formed in quartz plates. The preionization for the main discharge is generated from "V" cuts provided in a molybdenum ribbon sealed in a quartz tube.

Abstract: A high efficiency storage laser is achieved by pumping a Tm:LiYF.sub.4 laser from an electrically excited XeBr* fluorescer.

Abstract: The output power and efficiency of a gas discharge laser is substantially improved by the substitution of neon (Ne) for helium (He) as a buffer in the lasing medium. One embodiment of the invention is a pulsed excimer laser having a lasing gas comprising a mixture of krypton (Kr) and fluorine (F.sub.2). Use of Ne with the KrF excimer lasing medium further enables advantageous utilization of corona wire pre-ionization to initiate the main discharge of this type of laser.

Abstract: The onset of electric discharge instability in rare-gas monofluoride lasers pumped by electron beam sustained electric discharges (e.g., KrF*) is delayed by employing a laser gas mixture (such as 0.95 Ar, 0.05 Kr, and 0.005 F.sub.2) which includes a small amount of a halogen compound (NF.sub.3) having a rate coefficient for electron dissociative attachment which is much larger than that for fluorine (such as 0.0005 NF.sub.3). The addition of nitrogen trifluoride to the gas mixture modifies the halogen kinetics in a manner to reduce the effect that consumption of the fluorine fuel has on the growth of secondary electrons, and therefore the occurrence of instability in the discharge. The rare-gas metastable quenching coefficient for the nitrogen trifluoride is sufficiently small (on the order of six times smaller than that of the fluorine) so that the small amount of nitrogen trifluoride utilized to stabilize the discharge exerts little or no influence on the other laser processes.

Abstract: A rare-gas hydrogen-halide laser is improved by including or adding a predetermined quantity of a hydrogen donor additive to its gas mixture. The closed-off operation lifetime of lasers such as XeCl, KrCl, or XeBr are tripled by adding up to 0.05% hydrogen to the laser gas mixture.

Abstract: A gas laser is described which has as laser medium, a polyatomic excimer. Such a excimer is formed in a termolecular reaction between atomic particles which are raised to a metastable state by a pulse of electrical energy and a molecule which forms a complex with the excited metastable particle when a third particle or body interacts therewith to promote the termolecular reaction. After formation in the excited state and subsequent emission of coherent radiation, the particles and molecules return to the initial species.

Abstract: The onset of electric discharge instability in electron beam enhanced electric discharge lasers employing halides, such as rare-gas monohalides (e.g., KrF*) and mercury vapor halide (e.g., HgBr*), is delayed by limiting the production of secondary electrons during laser pulse generation, to account for critical loss of halogen or halide fuel. Secondary electron production is controlled, in order to extend the pulse duration before the onset of discharge instability, by temporal tailoring of the primary electron concentration in the electric discharge region across the temporal expanse of possible laser action; the population of primary electrons can be temporally restrained by temporal decrease of the current density of the electron gun output, as a function, for instance, of gun driving voltage, or by temporal defocusing of the electron beam so as to provide reduced densities within the electric discharge region.

Abstract: A cavity formed of Teflon to provide extended static fill lifetimes for gases containing halogens. A double cavity configuration provides structural integrity to the inner Teflon cavity by maintaining an identical multi-atmospheric pressure within the outer structural cavity to minimize tension on the Teflon inner cavity. Use of a quantity of the lasing gas in the outer cavity or a constituent of that gas minimizes contamination of the lasing gas.

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: The present invention relates to a system for generating extreme ultraviolet (XUV) radiation. The process utilizes pulsed plasmas to create a high density of ions in which non-linear frequency upconversion into the XUV region can occur. In particular, metals are utilized as the lasing medium in the present invention, since the ions of these metals do not absorb wavelengths in the XUV region and a significant level of XUV output may be obtained. Conventional UV lasers are utilized as the upconverters for the ionized metals.