Abstract: A split ring-resonator includes a substrate, an inner-trench or cavity formed into the substrate, the inner trench or cavity including a split, and an outer trench or cavity formed into the substrate around the inner trench or cavity, the outer trench or cavity including another split disposed at an opposite end of the split in the inner trench or cavity, wherein the inner trench or cavity and the outer trench or cavity are configured to receive an electrically conductive gas and/or plasma to form a split-ring resonator,

Abstract: Disruption of a gas atmosphere does not occur when a substrate is rotated 90° after it is carried into a laser processing apparatus. The substrate is carried such that a gas ejection port is positioned near a midportion of a first side of the substrate. The substrate is linearly moved to bring a center of the substrate near the gas ejection port and the substrate is horizontally rotated 90° about the center thereof. Because an edge portion of the gas ejection port does not go beyond a seal cover during rotation, disruption of the gas atmosphere that occurs due to the escaping of the gas does not occur.

Abstract: A carbon-dioxide (CO2) gas-discharge slab laser includes elongated discharge-electrodes in a sealed enclosure. Radio Frequency (RF) power is supplied to the electrodes via an impedance matching network and a co-axial electrical low inductance transmission line feed-through sealed to the enclosure. The feed-trough includes two spring contacts which are configured to be spring compression push-fit in grooves in edges of the discharge-electrodes. A central conductor of the feed-through is fluid cooled. A capacitor of the impedance matching network is assembled on the central conductor as an integral part of the feed-trough.

Abstract: Laser systems have a line-narrowed master oscillator and a power oscillator for amplifying the output of the master oscillator. The power oscillator includes optical arrangements for limiting the bandwidth of radiation that can be amplified. The limited amplification bandwidth of the power oscillator is relatively broad compared to that of the output of the master oscillator, but narrower than would be the case without the bandwidth limiting arrangements. The bandwidth narrowing arrangements of the power oscillator function primarily to restrict the bandwidth of amplified spontaneous emission generated by the power oscillator.

Abstract: A method and apparatus is disclosed for operating a laser output light beam pulse line narrowing mechanism that may comprise a nominal center wavelength and bandwidth selection optic; a static wavefront compensation mechanism shaping the curvature of the selection optic; an active wavefront compensation mechanism shaping the curvature of the selection optic and operating independently of the static wavefront compensation mechanism. The method and apparatus may comprise the nominal center wavelength and bandwidth selection optic comprises a grating; the static wavefront compensation mechanism applies a pre-selected bending moment to the grating; the active wavefront compensation mechanism applies a separate selected bending moment to the grating responsive to the control of a bending moment controller based on bandwidth feedback from a bandwidth monitor monitoring the bandwidth of the laser output light beam pulses. The active wavefront compensation mechanism may comprise a pneumatic drive mechanism.

Abstract: A laser-sustained plasma light source with a bulb for enclosing a relatively cool gas environment, and an electrode disposed at least partially within the gas environment. A power supply applies a potential to the electrode, where the power supply is sufficient to create a corona discharge at the electrode within the gas environment, and the power supply is not sufficient to produce an arc discharge within the gas environment. The corona discharge thereby produces a relatively heated gas environment. A pump laser source focuses a laser beam within the gas environment, where the laser beam is sufficient to ignite a plasma in the relatively heated gas environment, but is not sufficient to ignite a plasma in the relatively cool gas environment.

Abstract: A laser may comprise a ceramic body including a first wall and a second wall opposite the first wall, a first mirror positioned at first ends of the first and second walls, a second mirror positioned at second ends of the first and second walls opposite the first ends, the first and second walls and the first and second mirrors defining a slab laser cavity within the ceramic body. The laser may further comprise a first electrode positioned outside the laser cavity and adjacent to the first wall of the ceramic body and a second electrode positioned outside the laser cavity and adjacent to the second wall of the ceramic body, wherein a laser gas disposed in the laser cavity is excited when an excitation signal is applied to the first and second electrodes. In some embodiments, the first and second mirrors may form a free-space multi-folded resonator in the slab laser cavity. In other embodiments, the first and second mirrors may form a free-space unstable resonator in the slab laser cavity.

Abstract: Laser light wavelength control is provided by periodically predicting a next position of a light controlling prism using a model of the prism's motion characteristics. The prediction is then updated if a measurement of laser output wavelength is obtained. However, because the predictions are made without waiting for a measurement, they can be made more frequently than the laser firing repetition rate and the prism can be repositioned at discrete points in time which can occur more frequently than the laser firing events. This also reduces performance degradation which may be caused by being one pulse behind a laser measurement and the resultant laser control signal being applied.

Abstract: Two excimer lasers have individual pulsing circuits each including a storage capacitor which is charged and then discharged through a pulse transformer to generate an electrical pulse, which is delivered to the laser to generate a light pulse. The time between generation of the electrical pulse and creation of the light pulse is dependent on the charged voltage of the capacitor. The capacitors are charged while disconnected from each other. The generation of the electrical pulses is synchronized by connecting the capacitors together for a brief period after the capacitors are charged to equalize the charging voltages. The capacitors are disconnected from each other before they are discharged.

Abstract: A gas laser oscillator capable of initiating discharge, without applying excess voltage to a discharge tube, and correctly and rapidly judging the initiation of discharge. The oscillator has a laser power commanding part adapted to generate a laser power command including a pulse superimposed on a forefront of each step, a voltage applying part adapted to apply a voltage to a discharge tube based on the laser power command, a discharge tube voltage detecting part adapted to detect the discharge tube voltage, a discharge tube voltage monitoring part adapted to monitor the discharge tube voltage, and a discharge initiation judging part adapted to judge that the discharge is initiated when the difference, between a change rate of the monitored voltage and a change rate of the discharge tube voltage predetermined based on data obtained while the discharge is normally carried out, is smaller than a predetermined threshold.

Abstract: A temperature controller for a gas laser which controls temperatures of a plurality of temperature-controlled apparatuses including a first temperature-controlled portion requiring a high-precision temperature-control and a second temperature-controlled portion requiring a low-precision temperature-control as compared with the first temperature-controlled portion and allowing a temperature-control with a low or high temperature as compared with the first temperature-controlled portion, comprises a first temperature control portion generating a cooling agent or a heating agent for adjusting a temperature of each first temperature-controlled portion, a second temperature control portion generating a cooling agent or a heating agent for adjusting a temperature of each second temperature-controlled portion, a first piping system connecting the first temperature control portion and each first temperature-controlled portion in parallel, and a second piping system connecting the second temperature control portion an

Abstract: A gas discharge laser including a lasing gas between discharge electrodes and has a power supply for generating RF pulses to be delivered to the electrodes of the laser for energizing the lasing gas. A sequence of RF simmer pulses is delivered to the electrodes. The simmer pulses create sufficient free electrons in the lasing gas to facilitate subsequent ignition of the discharge while not causing laser action. RF lasing pulses having a longer duration than the simmer pulses are delivered to the electrodes to ignite the discharge and provide corresponding laser output pulses. Delivery of the simmer pulses is suspended during delivery of the lasing pulses to avoid amplitude or pulse-width modulation of the laser output pulses by the simmer pulses.

Abstract: A CO2 gas flow laser with multiple discharge modules places acoustic baffles between the discharge modules to suppress shock waves and ions passing between the discharge modules such as may disrupt the optical path of the laser. A catalyst may be placed in a center of a toroidal recirculation chamber of the laser and may have integrated filters to prevent catalyst particulates from coating the chamber optical windows.

Abstract: A degree of polarization control device includes: a calcium fluoride crystal substrate for transmitting a laser beam; a polarization monitor for measuring the degree of polarization of a laser beam transmitted through the calcium fluoride crystal substrate; and a controller for controlling the rotation angle of the calcium fluoride crystal substrate according to the degree of polarization measured by the polarization monitor; the calcium fluoride crystal substrate being formed by a flat plate having a laser beam entering surface and a laser beam exiting surface running in parallel with the (111) crystal face, the Brewster angle being selected for the incident angle, the rotation angle around the [111] axis operating as a central axis being controlled by the controller.

Abstract: A laser pulse from an ultrashort pulse laser (USPL) is fired into the atmosphere. The USPL pulse is configured to generate a plasma filament at a predefined target in the atmosphere, in which free, or “seed,” electrons are generated by multi-photon or tunneling ionization of the air molecules in the filament. A second pulse is fired into the atmosphere to form a heater beam that impinges on the plasma filament and thermalizes the seed electrons within the plasma filament, leading to the collisional excitation of the electrons in the filament. The excited electrons collisionally excite various electronic and vibrational states of the air molecules in the filament, causing population inversions and lasing, e.g., exciting the C3?u?B3?g(v=0?0) transition of the N2 in the atmosphere to cause lasing at 337 nm.

Abstract: Systems and methods generate laser pulse trains for material processing. In one embodiment, stable laser pulse trains at high repetition rates are generated from a continuous wave (CW) or quasi-CW laser beams. One or more laser pulses in the laser pulse train may be shaped to control energy delivered to a target material. In another embodiment, multiple laser beams are distributed to multiple processing heads from a single laser pulse, CW laser beam, or quasi-CW laser beam. In one such embodiment, a single optical deflector distributes multiple laser beams among respective processing heads.

Abstract: RF power is transmitted to a CO2 gas discharge laser form a source of RF power via a series combination of transmission line sections. The lengths and characteristic impedances of the transmission line sections are selected to transform the impedance of the RF power source to the operating impedance of the laser.

Abstract: This invention comprises a laser based on hydrogen molecules designated H2(1/p) wherein the internuclear distance of each is about a reciprocal integer p times that of ordinary H2. The H2(1/p) molecules are vibration-rotationally excited and lase with a transition from a vibration-rotational level to another lower-energy-level other than one with a significant Boltzmann population at the cell neutral-gas temperature (e.g. one with both ? and J=0). The vibration-rotational excitation may be by a direct collisional excitation or a light source such as a lamp, flash lamp, or internal or external plasma light source. Alternatively, the excitation may be by an energy exchange with an excited state species such as an activator may be by collision with an energetic particle from a particle excited activator molecule. The direct excitation and the excitation of the beam such as an electron beam or collision with an energetic species accelerated by power input to the cell.

Abstract: A gas-cooled laser device includes heat dissipative components, and housing walls made of a heat conducting material, in which one or more of the housing walls are provided with ventilation channels. At least one heat dissipative component is mounted on a plate of a heat conducting material, and the heat conducting plate is connected in a thermally conducting manner with the at least one housing wall that is provided with ventilation channels. The heat dissipative components can include heat dissipative optical components and heat dissipative non-optical components that are respectively arranged on different sides of the plate or are respectively arranged in different compartments on one side of the plate.

Abstract: A degree of polarization control device includes: a calcium fluoride crystal substrate for transmitting a laser beam; a polarization monitor for measuring the degree of polarization of a laser beam transmitted through the calcium fluoride crystal substrate; and a controller for controlling the rotation angle of the calcium fluoride crystal substrate according to the degree of polarization measured by the polarization monitor; the calcium fluoride crystal substrate being formed by a flat plate having a laser beam entering surface and a laser beam exiting surface running in parallel with the (111) crystal face, the Brewster angle being selected for the incident angle, the rotation angle around the [111] axis operating as a central axis being controlled by the controller.

Abstract: An apparatus/method may comprise a line narrowed pulsed lithography laser light source which may comprise: a seed pulse providing laser system which may comprise: a first pulsed seed laser producing seed pulses at a rate of X kHz; a second pulsed seed laser producing seed pulses at a rate of X kHz; an amplification system which may comprise: a first amplifier gain system which may comprise a first and a second pulsed gas discharge amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½X kHz on output pulses from the first seed laser; a second amplifier gain system which may comprise a first and a second pulsed amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½X kHz on output pulses from the second seed laser.

Abstract: An improved nozzle and iodine injector system for use in a COIL are disclosed. The improved nozzle is a two-dimensional, minimum length nozzle with a curved sonic line. The iodine injection system utilizes a series of slender struts for iodine injection into the oxygen stream through a series of small orifices that are located along the base of each strut. The struts are located within the nozzle such that the need for a diluent gas for the iodine is reduced. The use of the nozzle and iodine injection system, particularly when combined with the SOG disclosed in U.S. patent application Ser. No. 10/453,148, have the potential for yielding a highly efficient, high power, optically superior COIL device that is compact, scalable, can operate in space, and has good pressure recovery potential.

Abstract: An apparatus/method may comprise a line narrowed pulsed lithography laser light source which may comprise: a seed pulse providing laser system which may comprise: a first pulsed seed laser producing seed pulses at a rate of X kHz; a second pulsed seed laser producing seed pulses at a rate of X kHz; an amplification system which may comprise: a first amplifier gain system which may comprise a first and a second pulsed gas discharge amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½X kHz on output pulses from the first seed laser; a second amplifier gain system which may comprise a first and a second pulsed amplifier gain medium, each with a nominal center wavelength in the UV range, and each operating at ½X kHz on output pulses from the second seed laser.

Abstract: A gas laser oscillator includes a plurality of discharge tube arrays, each discharge tube array including a plurality of electrical discharge tubes, a support mechanism supporting the plurality of discharge tube arrays, and an optical part optically connecting the plurality of discharge tube arrays. The support mechanism includes a discharge tube linking holder and an elastic member. The elastic member joins the discharge tube linking holder to a first support rod arranged at an upper side as seen in a direction of gravity.

Abstract: A laser apparatus comprises a laser having a lasing chamber an inlet to the lasing chamber for a lasing gas containing a heavy noble gas and an outlet from the lasing chamber for the discharge of a flow of lasing gas, wherein the outlet is able to be paced in communication with the atmospheric through an adsorptive trap containing a selective adsorbent of the heavy noble gas. In operation, the heavy noble gas (xenon or krypton) is adsorbed in the trap. The trap may be taken to a remote site for the recovery of the heavy noble gas when it is approaching saturation.

Abstract: An apparatus is disclosed which may comprise a grating receiving light, a first prism moveable to coarsely select an angle of incidence of the light on the grating, and a second prism moveable to finely select an angle of incidence of the light on the grating. In one application, the apparatus may be used as a line narrowing module for a laser light source.

Abstract: A CO2 gas discharge laser includes a housing enclosing spaced-apart electrodes and a lasing gas. A laser resonator extends between the spaced-apart electrodes. An RF power supply provides RF power for creating a discharge in the lasing gas, causing laser radiation to be delivered by the laser resonator. The power of the output radiation is directly dependent on the RF power provided to the electrodes and inversely dependent of the temperature of the gas discharge. A signal representative of the discharge-temperature is used to adjust the RF power supplied to the electrodes such that the power of the output radiation is about constant.

Abstract: The invention relates to a two-stage laser system well fit for semiconductor aligners, which is reduced in terms of spatial coherence while taking advantage of the high stability, high output efficiency and fine line width of the MOPO mode. The two-stage laser system for aligners comprises an oscillation-stage laser (50) and an amplification-stage laser (60). Oscillation laser light having divergence is used as the oscillation-stage laser (50), and the amplification-stage laser (60) comprises a Fabry-Perot etalon resonator made up of an input side mirror (1) and an output side mirror (2). The resonator is configured as a stable resonator.

Abstract: A carbon-dioxide (CO2) gas-discharge slab laser includes elongated discharge-electrodes in a sealed enclosure. Radio Frequency (RF) power is supplied to the electrodes via an impedance matching network and a co-axial electrical low inductance transmission line feed-through sealed to the enclosure. The feed-trough includes two spring contacts which are configured to be spring compression push-fit in grooves in edges of the discharge-electrodes. A central conductor of the feed-through is fluid cooled. A capacitor of the impedance matching network is assembled on the central conductor as an integral part of the feed-trough.

Abstract: A method and apparatus are disclosed for controlling bandwidth in a multi-portion laser system comprising a first line narrowed oscillator laser system portion providing a line narrowed seed pulse to an amplifier laser system portion, may comprise utilizing a timing difference curve defining a relationship between a first laser system operating parameter other than bandwidth and the timing difference and also a desired point on the curve defining a desired timing difference, wherein each unique operating point on the curve corresponds to a respective bandwidth value; determining an actual offset from the timing difference at the desired point on the curve to an actual operating point on the curve; determining an error between the actual offset and a desired offset corresponding to a desired bandwidth; modifying the firing differential timing to remove the error between the actual offset and the desired offset.

Abstract: There is described a gas laser comprising a pair of substantially mutually parallel and opposed electrodes (17, 37), between which a volume is defined containing a gas in which said electrodes generate a discharge. At opposed ends of the electrodes, in said volume, mirrors (65) are arranged to define a resonant cavity. The electrodes form an integral part of two portions (5, 7) of a sealed housing (1), containing the gas and in which the mirrors and the electrodes are housed. The two portions (5, 7) forming the housing are electrically connected.

Abstract: An ultra-short pulse laser system comprising an amplifying laser medium for producing a laser emission, a laser resonator having at least one resonator mirror and a pump source has a gas-filled section with a filling gas, the latter consisting of a single gas or a filling gas mixture differing from the composition of air, whose nonlinear refractive index n2 substantially corresponds to that of air and which has a rotational Raman effect which is smaller in comparison with air.

Abstract: A system that performs an analysis of a gas laser application comprises a receiver component that receives an identity of a gas laser and parameters relating to intended use of the gas laser. An analysis component automatically generates a cost analysis of the gas laser application based at least in part upon the received identity and parameters, the cost analysis includes fixed cost and variable cost of the gas laser application.

Abstract: An oscillator housing includes a main body unit that is shaped into a frame and formed of a metallic material and a cover unit that is formed of a metallic material to cover openings of the main body unit, and has an outer wall that has an arc cross section perpendicular to the optical axis and extends in the optical axis direction and side walls that are connected to the both ends of the outer wall in the optical axis direction. When the cover unit is fixed to the main body unit with a fixing member, the outer wall having an arc shape is configured such that force is generated in the height direction towards the outside of the oscillator housing on the connecting portion of the cover unit with the main body unit.

Abstract: A pulsed CO2 laser is Q-switched by an intracavity acousto-optic (AO) Q-switch including an AO material transparent at a fundamental wavelength of the laser. In one example the AO material is germanium.

Abstract: A ring laser gyroscope that includes a cavity containing a gain medium, a plurality of reflective surfaces coupled to the cavity, and at least one medium exciter operable to excite the gain medium. The gain medium has naturally dispersive properties associated with an index of refraction. The reflective surfaces include at least a first reflective surface, a second reflective surface, and a third reflective surface. The first, second, and third reflective surfaces are positioned to reflect light between the plurality of reflective surfaces. The excited gain medium induces first and second laser fields within the cavity. The first and second laser fields operate at a lasing frequency corresponding to a negative slope of the index of refraction associated with the dispersive properties of the gain medium. The gain medium causes anomalous dispersion of the first and second laser fields passing through the gain medium.

Abstract: A laser includes a regenerative ring resonator that includes a discharge chamber having electrodes and a gain medium between the electrodes for producing a laser beam; a partially-reflective optical coupler, and a beam modification optical system in the path of the laser beam. The beam modification optical system transversely expands a profile of the laser beam such that the near field laser beam profile uniformly fills each aperture within the laser and such that the regenerative ring resonator remains either conditionally stable or marginally unstable when operating the laser at powers that induce thermal lenses in optical elements inside the regenerative ring resonator.

Abstract: Disclosed herein is a laptop-size high-order harmonic generation apparatus using near field enhancement. The laptop-size high-order harmonic generation apparatus using near field enhancement includes a femtosecond laser generator, light transfer means for transferring light output from the femtosecond laser generator, micro patterns formed of metallic thin films and configured to have nano-sized apertures for generating near field enhancement when the light output from the light transfer means passes through the micro patterns, a gas supply unit for supplying inert gas to the light when the light transferred through the light transfer means passes through the micro patterns, and a vacuum chamber for accommodating the micro patterns and the gas supply unit under a vacuum atmosphere.

Abstract: A mode selection technique in a laser is described wherein a recess is formed in a surface of a waveguide in the laser. The recess provides a region of free space propagation within the waveguide which preferentially selects the lowest order mode. A mode selective RF excited CO2 slab laser, having a stable resonator in the waveguide dimension and a negative branch unstable resonator in the non-waveguide dimension, is constructed and the position and size of the recess is considered to provide low order mode selection.

Abstract: The proposed gas discharge laser comprises extended solid main discharge electrodes, at each of which at least one ultraviolet pre-ionizer is placed, a gas flow area being formed by means of dielectric gas flow guides and the work surfaces of main electrodes and the pre-ionizers being placed outside of the gas flow area for illuminating a space between the main discharge electrodes through a gap defined between the main electrodes and dielectric guides. The proposed invention makes it possible to design a gas discharge laser for a high pulse repetition frequency mode with high-quality laser radiation.

Abstract: The higher efficiency and lower power consumption are realized in a laser system for generating a high-power short-pulse laser beam. The laser system includes a laser oscillator for generating a pulse laser beam by laser oscillation, plural amplifiers for sequentially inputting the pulse laser beam generated by the laser oscillator and amplifying the pulse laser beam, and a control unit for controlling the laser oscillator to perform burst oscillation and halting an amplification operation of at least one of the plural amplifiers in a burst halt period between burst oscillation periods.

Abstract: RF power is transmitted to a CO2 gas discharge laser form a source of RF power via a series combination of transmission line sections. The lengths and characteristic impedances of the transmission line sections are selected to transform the impedance of the RF power source to the operating impedance of the laser.

Abstract: An apparatus is disclosed which may comprise a grating receiving light, a first prism moveable to coarsely select an angle of incidence of the light on the grating, and a second prism moveable to finely select an angle of incidence of the light on the grating. In one application, the apparatus may be used as a line narrowing module for a laser light source.

Abstract: One aspect of the disclosed subject matter describes a gas discharge laser chamber. The gas discharge laser chamber includes a discharge region formed between a first electrode and a second electrode, a tangential fan for circulating gas through the discharge region, wherein the fan is proximate to an input side of the discharge region, an input side acoustic baffle proximate to the input side of the discharge region. The input side acoustic baffle includes a vanishing point leading edge, a vanishing point trailing edge, a gas flow smoothing offset surface aligning a gas flow from a surface of the input side acoustic baffle to an input side of a cathode support in the discharge region, a plurality of ridges separated by a plurality of trenches, wherein the plurality of ridges and the plurality of trenches are aligned with a direction of gas flow through the discharge region and wherein the plurality of ridges have a random pitch between about 0.3 and about 0.7 inch.

Abstract: A CO2 gas discharge laser includes a housing enclosing spaced-apart electrodes and a lasing gas. A laser resonator extends between the spaced-apart electrodes. An RF power supply provides RF power for creating a discharge in the lasing gas, causing laser radiation to be delivered by the laser resonator. The power of the output radiation is directly dependent on the RF power provided to the electrodes and inversely dependent of the temperature of the gas discharge. A signal representative of the discharge-temperature is used to adjust the RF power supplied to the electrodes such that the power of the output radiation is about constant.

Abstract: An RF excited gas discharge laser is disclosed including a housing holding the lasing gas. An electrode assembly is mounted within the housing. The electrode assembly includes a pair of elongated planar electrodes mounted in face to face relationship with a narrow gap therebetween. A pair of planar dielectric plates are positioned along the side edges of the gap to seal the discharge region. The plates extend part of the way into the gap from both sides edges of the electrodes. The inner surfaces of the electrodes are provided with an opposed trench in the region surrounding the inner edges of the plates. In this way, the exposure of the inner edges of the plates to the discharge is minimized improving performance.

Abstract: RF power is transmitted to a CO2 gas discharge laser form a source of RF power via a series combination of transmission line sections. The lengths and characteristic impedances of the transmission line sections are selected to transform the impedance of the RF power source to the operating impedance of the laser.

Abstract: At least either of the light entering plane or the light exiting plane is parallel to the (111) crystal face of the CaF2 crystal and the laser beam entering from the entering plane passes through the plane located between the [111] axis and the first azimuth axis in the locus of rotation of the [001] axis around the [111] axis and including the [111] axis and the first azimuth axis, the plane located between the [111] axis and the second azimuth axis in the locus of rotation of the [010] axis around the [111] axis and including the [111] axis and the second azimuth axis or the plane located between the [111] axis and the third azimuth axis in the locus of rotation of the [100] axis around the [111] axis and including the [111] axis and the third azimuth axis and exits from the exiting plane.

Abstract: The invention relates to a two-stage laser system well fit for semiconductor aligners, which is reduced in terms of spatial coherence while taking advantage of the high stability, high output efficiency and fine line width of the MOPO mode. The two-stage laser system for aligners comprises an oscillation-stage laser (50) and an amplification-stage laser (60). Oscillation laser light having divergence is used as the oscillation-stage laser (50), and the amplification-stage laser (60) comprises a Fabry-Perot etalon resonator made up of an input side mirror (1) and an output side mirror (2). The resonator is configured as a stable resonator.

Abstract: The present invention provides a control system for a modular high repetition rate two discharge chamber ultraviolet gas discharge laser. In preferred embodiments, the laser is a production line machine with a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. Feedback timing control techniques are provided for controlling the relative timing of the discharges in the two chambers with an accuracy in the range of about 2 to 5 billionths of a second even in burst mode operation. This MOPA system is capable of output pulse energies approximately double the comparable single chamber laser system with greatly improved beam quality.