Abstract: A single chamber gas discharge laser system having a pulse power source for producing electrical discharges at the rate of at least 1000 pulses per second. The discharge along with laser optics create two short lived gain media, one for producing a seed beam and the other for amplifying the seed beam. Laser gas circulation around a chamber circulation path is provided and the electrodes and discharges are arranged so that debris from one of the gain media is not circulated to the other gain media during discharges until the debris has made a loop around at least 90% of the chamber circulation path.

Abstract: A high repetition rate, compact, modular gas discharge, ultraviolet laser. The laser is useful as a light source for very rapid inspections of wafers in an integrated circuit fabrication process. It is also useful for reticle writing at very rapid rates. A preferred embodiment operates at pulse repetition rates of 1000 to 4000 Hz and is designed for round-the-clock production line operation. This preferred embodiment comprises a pulse control unit which controls the timing of pulses to an accuracy of less than 4 nanoseconds. Preferred embodiments of this gas discharge laser can be configured to operate with a KrF gas mixture, an ArF gas mixture or an F2 gas mixture, each with an approximate buffer gas, producing 248 nm, 197 nm or 157 nm ultraviolet light pulses.

Abstract: Heat is removed from an equipment enclosure using a recirculating air flow loop that is confined entirely within the enclosure. A segment of the air flow loop is directed onto heat-generating components, contained within housings mounted inside the enclosure. A segment of the air flow loop carries heated air to a heat exchanger, which transfers heat to flowing liquid. A portion of the air flow loop traverses through the ductless air volume confined between the housings and inner walls of the enclosure. Blowers to drive the air flow are typically mounted within or on a housing. Heat exchangers are also typically mounted on a housing. Embodiments of the present invention enable a single heat exchanger or multiple heat exchangers to cool multiple electronic components without complicated ducting and without exhausting heated air into a controlled manufacturing environment, e.g. a clean room.

Abstract: The invention provides an once through fan for an excimer laser apparatus having a reduced vibration and being capable of increasing a rotational speed. In order to obtain this, in an once through fan (1) for an excimer laser apparatus provided with a blade portion (6) having a plurality of blades, a rotary shaft (4) for rotating the blade portion and a magnetic bearing (7) rotatably supporting the rotary shaft in a non-contact manner so as to circulate a laser gas sealed within a chamber (2) in accordance with a rotation of the blade portion, a rotor (21) of a motor (23) installed within the chamber (2) and rotating the rotary shaft (4) is mounted on an outer peripheral portion of the rotary shaft, and at least one magnetic bearing (7, 7) for supporting the rotary shaft is arranged in each of both sides in an axial direction of the rotor.

Abstract: This invention relates to an excimer laser oscillation apparatus which has a laser chamber which stores a laser gas containing a gas mixture of at least one inert gas selected from the group consisting of Kr, Ar, and Ne, and F2 gas, and in which an inner surface thereof has a reflection-free surface with respect to light of a desired wavelength of 248 nm, 193 nm, or 157 nm, and the uppermost surface of the inner surface consists of a fluoride, an optical resonator which is made up of a pair of reflection mirrors arranged to sandwich the laser chamber therebetween, and in which the reflectance of the reflection mirror on the output side is 90% or more and microwave introduction means, arranged on the laser chamber, for continuously exciting the laser gas in the laser chamber.

Abstract: A gas discharge laser having a laser chamber with two elongated erodable electrode elements, at least one of said electrode element having a generally blunt blade-shaped portion comprised of a material having high electrical conductivity with a flow shaping dielectric fairing positioned on each of two sides of said blunt blade-shaped portion. A pulse power system provides electrical pulses at rates of at least 1 KHz. A blower circulates laser gas between the electrodes at speeds of at least 10 m/s and a heat exchanger is provided to remove heat produced by the blower and the discharges.

Abstract: A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion.

Abstract: A reliable, modular, production quality F2 excimer laser capable of producing, at repetition rates in the range of 1,000 to 2,000 Hz or greater, laser pulses with pulse energies greater than 10 mJ with a full width half, maximum bandwidth of about 1 pm or less at wavelength in the range of 157 nm. Laser gas concentrations are disclosed for reducing unwasted infrared emissions from the laser. Also disclosed are UV energy detectors which are substantially insensitive to infrared light. Preferred embodiments of the present invention can be operated in the range of 1000 to 4000 Hz with pulse energies in the range of 10 to 5 mJ with power outputs in the range of 10 to 40 watts. Using this laser as an illumination source, stepper or scanner equipment can produce integrated circuit resolution of 0.1 &mgr;m or less. Replaceable modules include a laser chamber and a modular pulse power system.

Abstract: A method is provided for determining the status of a gas mixture of a laser system including a gas discharge laser which generates an output beam and has a discharge chamber containing a gas mixture within which energy is supplied to the gas mixture by a power supply via application of a driving voltage to a discharge circuit. A master data set of an output parameter such as any of output beam energy, bandwidth, spectrum width, long axial beam profile, short axial beam profile, beam divergence, energy stability, energy efficiency, width of the discharge, temporal beam coherence, spatial beam coherence, spatial pulse width, amplified spontaneous emission and temporal pulse width versus an input parameter such as driving voltage is generated corresponding to an optimal gas mixture status, preferably after a new fill and typically at the factory, and alternatively following a new fill at the fab.

Abstract: A system is provided for delivering a laser beam of wavelength less than 200 nm from a laser, such as an F2 laser or ArF laser, through a sealed enclosure sealably connected to the laser, and preferably to another housing, leading ultimately to a workpiece. The enclosure is preferably evacuated and back-filled with an inert gas to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter or alternatively, an inert gas flow is established and maintained within the enclosure during operation of the laser. The inert gas preferably has high purity, e.g., more than 99.5% and preferably more than 99.999%, wherein the inert is preferably nitrogen or a noble gas. The enclosure is preferably sealed by a window transparent to the sub-200 nm radiation for preventing contaminants generated in the enclosure from entering the housing and contaminating surfaces therein. The enclosure is preferably made of steel and/or copper, and the window is preferably made of CaF2.

Abstract: Methods and structural changes in gas discharge lasers for minimizing wavelength chirp at high pulse rates. Applicants have identified the major cause of wavelength chirp in high pulse rate gas discharge lithography lasers as pressure waves from a discharge reflecting back to the discharge region coincident with a subsequent discharge. The timing of the arrival of the pressure wave is determined by the temperature of the laser gas through which the wave is traveling. During burst mode operation, the laser gas temperature in prior art lasers changes by several degrees over periods of a few milliseconds. These changing temperatures change the location of the coincident pressure waves from pulse to pulse within the discharge region causing a variation in the pressure of the laser gas which in turn affects the index of refraction of the discharge region causing the laser beam exiting the rear of the laser to slightly change direction.

Abstract: The invention relates to a machining head and to a process for the surface machining of workpieces by means of a laser beam, in which coating, alloying in the area close to the surface or dispersion of a peripheral zone of the base material with powder particles can be carried out using a pulverulent filler supplied. The invention is intended to make it possible to maintain, independently of direction, a virtually constant mass flow rate of the powder supplied, the intention being to form a uniform hollow powder jet.

Abstract: A gas laser device. The device includes a laser chamber having at least one active gas and a device for purifying gas. The purified gas is in communication with the free exchange of gas with the chamber. This device may be used with high powered gas lasers.

Abstract: To provide a cross-flow fan that is ideal for use in an excimer laser device or fluoride laser device that is capable of high-speed rotation, that has high mechanical strength even at high-speed rotation and that does not suffer deformation, a rotating shaft is mounted passing through the center of cross-flow fan for a discharge excitation gas laser device. Use of the rotating shaft facilitates alignment of the rotating shaft and high-speed rotation is possible because the mechanical strength is raised. Furthermore, magnetic bearings can be used since misalignment does not develop. The flow velocity is not adversely affected even if a rotating shaft, as noted above, is utilized since a cross-flow fan for gas circulation in an excimer laser device is used under high-head, low-flow velocity conditions.

Abstract: A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion.

Abstract: A magnetic bearing enables to rotatably support a levitated body non-contactingly disposed in a hermetically sealed container filled with a gaseous process substance of a corrosive nature, while without contaminating the gaseous environment and suffering from corrosion. The magnetic bearing has an electromagnet for supporting a levitated body, a displacement sensor for detecting a levitated position of the levitated body, and a controller for supplying signals and excitation currents to the displacement sensor and the electromagnet through cables. An electromagnet target of the magnetic bearing that generates variations in magnetic fields due to rotation of the levitated body, is constructed of a single piece of ferromagnetic material, and is provided with an electrical insulation structure oriented parallel to magnetic fluxes generated by the electromagnet.

Abstract: There is provided an excimer laser device capable of producing a stable oscillation even at a high repetition rate of 4 kHz. This gas laser device is comprised of a laser chamber having laser gas filled therein; a pair of main discharge electrodes arranged in the laser chamber; a cross-flow fan for circulating the laser gas within the laser chamber at least between the main discharge electrodes; and a diameter of the cross-flow fan is 150 mm or less, its peripheral speed being 25.0 m/s or more.

Abstract: An excimer laser system with a real time fluorine monitor and an automatic fluorine control system to permit precise control of the fluorine concentration within the laser chamber. Cleaned laser gas is extracted from the laser chamber and directed through an F2 sample cell prior to returning to the chamber through one of the chamber window housings. A UV light beam is directed through the F2 sample cell and the amount of absorption of the light is measured. In preferred embodiments the absorption is measured by detecting with a photo detector the amount of light which passes through the cell. The photo detector provides a feedback signal which is used by a laser controller to automatically control fluorine concentration in the chamber to within desired ranges. In another preferred embodiment an acoustic detector detects acoustic signals resulting from absorbed light pulses. This invention provides a substantially real time measurement of fluorine concentration.

Abstract: In a method for determining the life of a laser light source for use with an exposure apparatus using KrF or ArF excimer laser as a light source for exposure, the method for determining the life of the laser light source is implemented by subjecting an excimer laser light source to single oscillation by blocking a pulse light, acquiring data relating to plural parameters for learning a periodical variation of the excimer laser light source and its structuring parts through an interface, and determining the life of the excimer laser light source on the basis of the data acquired. Those data is acquired on a regular basis in accompany with the work for exchanging gases at the time of exchanging gases for the excimer laser light source.

Abstract: A laser apparatus comprises a plurality of laser beam sources which use, as laser media, mixed gases containing at least one common gas component; at least one common gas supply source for supplying, to the respective laser beam sources, the common gas component for constituting the mixed gases; and one or more gas flow amount-adjusting units for adjusting flow amounts of the common gas component supplied from the common gas supply source and other gas components for constituting the mixed gases so that the gas components are supplied to the respective gas laser beam sources. It is unnecessary to provide gas tanks for each of the laser beam sources. The arrangement of the gas supply equipment is simplified, and the safety is improved. A plurality of the laser apparatuses are preferably installed to a circuit element production line provided with a plurality of exposure apparatuses.

Abstract: An excimer laser generating system includes a laser chamber whose inner surface is covered with a fluorine-passivated surface. Preferably, the surfaces of a blower and heat exchanger disposed in the laser chamber are also covered with a fluorine-passivated surface. The fluorine-passivated surface may be formed of a wide variety of materials including an aluminum oxide film, a fluoride film containing aluminum fluoride and magnesium fluoride, iron fluoride, and nickel fluoride. Preferably, the excimer laser generation system includes a gas supply system having an inert gas purging system so that gas sources can be replaced without exposing the inside of gas supply pipes to atmosphere. With the above arrangement, the excimer laser generating system can generate a laser beam pulse whose energy and shape are maintained constant for a long period of operation time without encountering serious degradation.

Abstract: A laser chamber with a circuitous gas return path dissipates shock waves. In one embodiment, the laser chamber includes a heat exchanger with a large surface area that defines an aerodynamic passage through which gas circulates in the laser chamber. The passage through which the gas circulates directs shock waves away from the discharge region so that the shock waves may dissipate elsewhere in the laser chamber. In addition, the large surface area of the heat exchanger efficiently cools the thermally energetic gas within the laser chamber. In another embodiment, ancillary chambers that are fluidically coupled to the main laser chamber are provided to permit shock waves to be directed away from the discharge area and to be dissipated within the ancillary chambers. Openings to the ancillary chambers are positioned such that shock waves generated by the electrode structure of the laser chamber may propagate directly into the ancillary chamber, where the shock waves then dissipate.

Abstract: A method is provided for determining the status of a gas mixture of a laser system including a gas discharge laser which generates an output beam and has a discharge chamber containing a gas mixture within which energy is supplied to the gas mixture by a power supply via application of a driving voltage to a discharge circuit. A master data set of an output parameter such as any of output beam energy, bandwidth, spectrum width, long axial beam profile, short axial beam profile, beam divergence, energy stability, energy efficiency, width of the discharge, temporal beam coherence, spatial beam coherence, spatial pulse width, amplified spontaneous emission and temporal pulse width versus an input parameter such as driving voltage is generated corresponding to an optimal gas mixture status, preferably after a new fill and typically at the factory, and alternatively following a new fill at the fab.

Abstract: A blower assembly for circulating gases in a laser chamber. The blower assembly includes a driving assembly operatively engaged to a drive side shaft for rotating a fan assembly. A first bearing assembly supports the drive side shaft. The blower assembly may further include an idle side shaft for supporting the fan assembly and a second bearing assembly circumscribing the idle side shaft. The driving assembly includes a motor disposed over a rotor. The fan assembly includes a pair of hubs supporting a plurality of blades. The first and second bearing assemblies comprise a ceramic compound, such as silicon nitride (Si3N4), and are lubricated with a synthetic oil, such as perfluoropolyalkylether (PFPE).

Abstract: A tangential fan, configured to recirculate a lasing gas mixture, has blade members, which are twisted in a substantially helical fashion about the rotation axis of the fan. The circumferential number of blade members can be constant variable between the end flanges. The circumferential position of blade members can shift monotonically or reversibly between the two ends. A tangential fan in accordance with the invention can be made using a conventional method of brazing together individually stamped and formed blade members and hub members. Finishing processes typically include post-machining, electropolishing, and electroless nickel coating.

Abstract: A support bar member for supporting an electrode member of a pulsed laser system is described. The support bar member includes an aerodynamic nose configured to reduce an aerodynamic load applied against a blower assembly of the laser system by the support bar member. The nose provides an aerodynamic cut-off region on the support bar member such that, when the blower assembly is operating, the blower assembly does not vibrate significantly.

Abstract: There is disclosed a metal vapour laser comprising a discharge tube having a buffer gas therein and operating at high temperature, the buffer gas including a laser output power enhancing substance in an amount sufficient to substantially increase the power output of the laser. There is also disclosed a process for operating a metal vapour laser of the invention.

Abstract: A laser output detector is provided which comprises: a convertor unit having a light sampling port to be located adjacent a projecting portion of a laser beam projector for sampling a fraction of a convergent portion of a laser beam projected from the laser beam projector or a fraction of a non-convergent portion of the laser beam outside the convergent portion of the laser beam, and adapted to convert the sampled laser beam fraction into an electrical signal; and a detection circuit for computing the energy amount of the projected laser beam on the basis of the electrical signal outputted from the convertor unit.

Abstract: An excimer laser system with an automatic fluorine control system to permit precise control of the fluorine concentration within an F.sub.2 "sweet spot" in a gas discharge laser chamber. This is done with a computer control system which monitors laser parameters, determines .DELTA.E/.DELTA.V, the change of pulse energy with voltage, and automatically and precisely controls the fluorine concentration based on .DELTA.E/.DELTA.V without the need to actually measure the fluorine concentration.

Abstract: A tangential fan and cutoff assembly for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end, and/or a tapered anode assembly. The number of blade members can be constant or variable between ends. The circumferential position of blade members can shift monotonically or reversibly between ends. Blade members are stiffened by optimally selecting the number and placement of hub members to control the natural vibration frequency of the fan. Methods of forming tangential fans include casting, and machining from a solid block. Monolithic structures can be joined, typically by electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Tangential fans produced have mechanical rigidity, accurate tolerances, and low contaminant concentrations. Blade members can be formed into air foil shapes.

Abstract: Dispersion of energy density in the longitudinal direction of excimer laser shaped into a linear beam is corrected. A gas introducing system which extends in the longitudinal direction of an oscillator and which is provided with a large number of gas injecting holes is provided within the oscillator. It allows to suppress dispersion of laser oscillating positions and to suppress the dispersion of irradiation energy density within the linear laser beam.

Abstract: A tangential fan for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end. The number of blade members can be constant or variable between ends. The circumferential position of blade members can shift monotonically or reversibly between ends. Blade members are stiffened by one or more transverse annular hub members. A method of forming a tangential fan involves forming monolithic structures by casting or by machining from a solid block. Two or more monolithic structures can be joined together, typically by electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Tangential fans produced have mechanical rigidity, accurate tolerances, and low contaminant concentrations. Methods provided by the invention facilitate forming of blade members into an air foil shape. Finishing processes typically include post-machining, electropolishing, and electroless nickel coating.

Abstract: A tangential fan and cutoff assembly for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end, and/or a tapered anode assembly. The number of blade members can be constant or variable between ends. The circumferential position of blade members can shift monotonically or reversibly between ends. Blade members are stiffened by optimally selecting the number and placement of hub members to control the natural vibration frequency of the fan. Methods of forming tangential fans include casting, and machining from a solid block. Monolithic structures can be joined, typically by electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Tangential fans produced have mechanical rigidity, accurate tolerances, and low contaminant concentrations. Blade members can be formed into air foil shapes.

Abstract: An excimer laser system with a fluorine control having a fixed volume inject bottle in which fluorine is injected prior to it being injected into the laser chamber. A manifold and feedback control system is provided to permit precise injection at rates approaching continuous fluorine injection. The system permits the laser to be operated in a small sweet spot as measured by a narrow range of charging voltage.

Abstract: A compact multiwavelength laser arrangement includes a reflective waveguide grating combined with two arrays of reflecting waveguide elements located in separate focal regions formed by the grating. The laser uses a folded imaging arrangement with nonoverlapping focal regions that eliminates unwanted resonances of previous reflective arrangements. The laser's advantages over existing transmissive laser arrangements include reduced size, faster response time, and increased number of wavelengths.

Abstract: A tangential fan with cutoff assembly for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end, and/or a tapered anode assembly. The number of blade members can be constant or variable between ends. The circumferential positions of blade members can shift monotonically or reversibly between ends. Blade members can be formed into air foil shapes and are stiffened by one or more transverse annular hub members. Processes for making tangential fans include soldering, casting, and machining from a solid block. Monolithic structures can be joined, typically by soldering or electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Soldering produces substantially silicon-free assemblies. Tangential fans produced in accordance with the invention have improved mechanical rigidity, accurate tolerances, and low contaminant concentrations.

Abstract: The present invention provides a reliable modular production quality excimer laser capable of producing 10 mJ laser pulses in the range of 1000 Hz to 2000 Hz or greater. Replaceable modules include a laser chamber; a pulse power system comprised of three modules; an optical resonator comprised of a line narrowing module and an output coupler module; a wavemeter module, an electrical control module, a cooling water module and a gas control module. Important improvements have been provided in the pulse power unit to produce faster rise time and improved pulse energy control. These improvements include an increased capacity high voltage power supply with a voltage bleed-down circuit for precise voltage trimming, an improved commutation module that generates a high voltage pulse from the capacitors charged by the high voltage power supply and amplifies the pulse voltage 23 times with a very fast voltage transformer having a secondary winding consisting of a single four-segment stainless steel rod.

Abstract: A reliable, modular, production quality narrow-band KrF excimer laser capable of producing 10 mJ laser pulses at 1000 Hz with a bandwidth of about 0.6 pm or less. The present invention is especially suited to long-term round-the-clock operation in the lithographic production of integrated circuits. Improvements over prior art lasers include a single upstream preionizer tube and acoustic baffles. A preferred embodiment includes reduced fluorine concentration, an anode support bar shaped to reduce aerodynamic reaction forces on blower bearings, a modified pulse power system providing faster pulse rise time, an output coupler with substantially increased reflectivity, a line narrowing module with CaF prism beam expanders, a more accurate wavemeter, a laser computer controller programmed with new and improved pulse energy control algorithm.

Abstract: An excimer laser with a laser gas containing fluorine in which the fluorine concentration is maintained continuously at or substantially at desired predetermined levels. A real time or substantially real time fluorine monitor provides a feedback signal to a fluorine flow control system which provides continuous fluorine injection flow into the laser chamber to precisely compensate for fluorine depletion and maintain fluorine concentration precisely at desired levels. In a preferred embodiment, fluorine detector which may be a chemical detector periodically measures the fluorine concentration in laser gas discharged from the laser in order to calibrate the real time or substantially real time fluorine monitor. In a second preferred embodiment, the continuous inlet flow is from two gas sources, one containing fluorine, a noble gas and a buffer gas and the other containing only the noble gas and the buffer gas.

Abstract: In a gas laser blower, the lower end opening of the oil passage (14) extends below the liquid level of the oil reservoir (17), so that the internal chamber (18) of housing and the oil passage (14) are separated by the oil within the oil reservoir. Further, a cylindrical guard (24) is disposed around the lower bearing (6) which supports the shaft so that the oil and oil mist scattered from the bearing are caught by the guard (24) and is returned to the oil reservoir.

Abstract: A nozzle for mixing of two reacting fluids wherein the first reactant, flowing across the nozzle, exhibits a variation in reactivity towards the second fluid, introduced through the nozzle and mixing and reacting with the first fluid within the nozzle, and wherein the nozzle is configured to permit this second fluid to be introduced in a way as to compensate for the variation in reactivity and to produce uniform reactant mixture from the two fluids.

Abstract: A gas laser design (10) includes, an elongated sealed tube (21) filled with a gas, a power supply for exciting the gas, an optical resonator (24,25) for producing directional optical energy, and a fan/electronics package assembly (50), all of which are surrounded and enclosed by an external housing (30,70,90) forming a passageway in the space between the tube and the housing for providing cooling air therethrough. The passageway is divided into two physically separated cooling air paths by a horizontal surface (21a or 41). The lower space is a dual L-shaped path defining the first cooling air path downwardly at the inlet end of the tube in the vertical air channels (31,32) formed by the contoured shape of the tube and rearwardly (33) through the spaces (27,29) between the horizontal fins (26,28) of the tube to an outlet (101) at the rear of the tube.

Abstract: A gas laser apparatus for generating a laser beam along a light beam axis, comprises, a gas as a laser medium, a dielectric tube through which the gas passes, and which surrounds the light beam axis, a pumping source generating an electric discharge through the gas existing in the dielectric tube to excite the gas so that a laser light is generated from the excited gas, and a gas blower blowing the gas into the dielectric tube, wherein the gas blower forms a circumferential flow direction component of the gas in the dielectric tube.

Abstract: A gas laser includes an enclosure forming a first chamber, a second chamber and a lasing chamber which communicates through a first opening to the first chamber and through a second opening to the second chamber. The lasing chamber has a pair of reflectors defining a Fabry-Perot cavity. Separate inlets enable different gases to be introduced into the first and second chambers. A first cathode within the first chamber is provided to produce positive ions which travel into the lasing chamber and a second cathode of a pin-hollow type within the second chamber is provided to produce negative ions which travel into the lasing chamber. A third inlet introduces a molecular gas into the lasing chamber, where the molecular gas becomes excited by the positive and negative ions and emits light which lases in the Fabry-Perot cavity.

Abstract: A continuous wave photolytic iodine laser has a gain cell for receiving a continuous supply of gaseous fuel. The gain cell is connected to laser beam transfer optics, a laser resonator for shaping a laser beam, and a lamp. The lamp is driven by a microwave subsystem such that a laser gain medium is pumped through the gain cell. The continuous wave photolytic iodine laser of the present invention incorporates a closed loop fuel system for presenting gaseous fuel to the gain cell at a rate sufficient to sweep any lasing by-products out of the gain cell, thereby preventing quenching of the lasing process. The fuel system also includes a condenser for converting the gaseous fuel to a liquid after it has passed through the gain cell, a scrubber for removing the by-products of the lasing process from the fuel, and an evaporator for converting the recycled liquefied fuel back to a gas. The closed loop fuel system also includes a pump for pressurizing and transporting the liquefied fuel.

Abstract: There is provided a cylindrical valve 20 for placement in the flow path of a singlet-delta oxygen generator 12 that feeds O.sub.2.sup.* to a chemical laser gain medium 14. The feed path 22 includes a sharp 90.degree. bend 24 that causes fluid velocity variations in O.sub.2.sup.* entering the gain medium 14. Integral with the valve 20 is a tubular structure 12 having a partial circumferential radially extending surface 44 fitted with "O" ring for sealing and opening the feed path between the "O.sub.2.sup.* " generator 12 and gain generator 14. A series of vanes 32, 34, 36 disposed in velocity control zones 50, 52, 54 and 56 are integral with the valve 20 for leveling out the velocity variations and controlling the wake formation 58, 59 and 60 in the O.sub.2.sup.* entering the gain generator 14.

Abstract: A trussed cross-flow blower comprising truss elements on the inside of a cylindrically-shaped cross-flow blower element form at least three trusses which provide rigidity to the blower element. Preferably three trusses are provided, and they are located at radial 120.degree. spacings.

Abstract: A sealed gas laser tube (10) has a pair of electrically insulated electrodes (53, 54) supported in the tube (11) adapted to couple to an external RF supply (30).

Abstract: A gas laser oscillator has at least a partial reflection unit and a total reflection unit, each of which comprises an extension unit for connecting between a gas introducing unit and a fixed block unit. The gas introducing unit has a gas inlet port for circulating laser gas in a laser tube, and the fixed block unit is provided for fixing a reflector. A gas inlet port of the gas introducing unit is arranged with a predetermined interval of 120 mm or more so that the reflectors are free from contamination by floating powders and deterioration by ultraviolet lays.

Abstract: In a blower for compulsorily circulating a laser gas for a gas laser apparatus, a shaft (2) of an impeller (1) is fitted with an intermediate member (66) that rotates together therewith, and rings (641, 642) are fitted individually in annular grooves (651, 652) formed on the intermediate member (66). On the other hand, a bearing holder (60) for holding a bearing (5) that supports the shaft (2) is provided with a ring holder (63) having an inner wall kept normally in contact with the respective outer peripheral surfaces of the rings (641, 642). As a result, narrow axial gaps between the rings (641, 642) and the annular grooves (651, 652) prevent gaseous impurities from getting into a gas laser circulation path through a bearing (5).