Abstract: This invention relates generally to custom optical filters such as filters relating to, flat-top WDM multiplexer/demultiplexers, flat-top and peaky comb filters or reconfigurable add & drop filters. The embodiment disclosed below is based on mid-dispersion wavelength bands processing, wherein the optical spectrum is dispersed in two steps; in-between these two steps, the wavelength bands are manipulated in the focal plane, for example by being moved, reflected, absorbed, inverted, magnified or reduced to achieve a particular result. A masked mirror or masked transmissive element selects wavelength by position. The mask shape for relatively complex filtering functions is much simpler than currently used for collimated beams because of the correlation between position and wavelength. Inversion of channel bands or movement of channel bands in two dimensions in the focal plane, in particular, enables the construction of numerous useful devices.

Abstract: Disclosed is an external cavity diode laser system that includes a dispersive unit; a gain element producing coherent light incident upon the dispersive unit, and the dispersive unit dispersing the incident coherent light into dispersed light, the dispersed light comprising a reflected diffraction beam and at least one of angularly-separated source spontaneous emission or angularly-separated amplified spontaneous emission; a guiding dispersion unit that guides the dispersed light diffracted upon it from the dispersive unit while maintaining an angular separation between the reflected diffraction beam and at least one of angularly-separated source spontaneous emission or angularly-separated amplified spontaneous emission; and a physical filtering device that physically filters the reflected diffraction beam from the spatially separated at least one of angularly-separated source spontaneous emission or angularly-separated amplified spontaneous emission guided to the physical filtering device by the guiding unit

Abstract: The invention pertains to a method and to a device for resonance enhancement, in particular for tunable frequency conversion of continuous laser radiation, in particular, with a resonator of mirrors and at least one refractive element. The purpose of the invention is to develop a method and a device of the described type, so that the frequency conversion of continuous laser radiation, in particular, will occur at high efficiency while avoiding the described disadvantages, and so that an improved tunability will be assured over the greatest possible wavelength range with regard to the incident wavelengths; this problem is solved in that a tuning of resonator length is performed by translation of at least one refractive element P. The resonator is formed from a first mirror M1, a second mirror M2, and of a refractive element P designed in trapezoidal shape, which performs the function of a prism.

Abstract: The present invention features a reconfigurable resonant cavity specifically for use with a slot radiator. A series of internal planes with frequency-selective materials disposed on their top surfaces, in conjunction with switchable shorting pins, is used to reconfigure the cavity's resonant frequency. PIN diodes, MEMS or other photonically or electrical activated switching devices may be used to selectively “activate” shorting pins. A single resonant cavity may be electrically reconfigured to operate at two, three, or even more different frequency bands.

Abstract: A method for locating the position for a concave mirror alignment device on a RLG block, comprising the following steps: 1) mount a “log” onto a CNC machine, 2) select several points along the length of the log for measurement; 3) measure the mirror mounting surface radial distances at each of the several points from the “front” of the log; 4) measure the surface radial distances at each of the several points from the “rear” of the log; 5) determine the radius, and ultimately the diameter, of a circle tangent to the mirror mounting sides of the log, for each of the several selected points; 6) determine a “best fit” equation to describe the diameters as a function of position along the log; 7) determine the offset along the x axis for the mirror mounting device of each block within the log.

Abstract: A compact solid-state laser has its cavity formed by the reflection surface of a gain crystal and the reflection surface of a chirped mirror. The pumping light is incident to the cavity through the reflection surface of the gain crystal or the chirped mirror, from which the laser output is led out. Forming the cavity solely by the gain crystal and chirped mirror enables the elimination of additional component parts for the compensation of dispersion, so that the whole laser system can be made compact and, consequently, the repetition frequency can be made higher.

Abstract: Heretofore, if the beam size of the resonance mode is made small in a long resonator length, there arises a problem that the operation of the laser resonator becomes easy to be unstable and hence the adjustment thereof becomes difficult. A laser resonance includes: a laser material; a telescope for magnifying a laser beam which has been made incident from the laser material and for reducing a laser beam which has been made incident from the side opposite thereto; a flat reflecting mirror for reflecting the laser beam which has been made incident from said telescope; a telescope for magnifying the laser beam which has been reflected by the flat reflecting mirror to be reduced by the telescope and to be amplified by the laser material to be made incident thereto; and a flat reflecting mirror for reflecting the laser beam which has been made incident from the telescope.

Abstract: A frequency conversion system comprises first and second gain sources providing first and second frequency radiation outputs where the second gain source receives as input the output of the first gain source and, further, the second gain source comprises a Raman or Brillouin gain fiber for wave shifting a portion of the radiation of the first frequency output into second frequency radiation output to provided a combined output of first and second frequencies. Powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Raman/Brillouin amplifier or oscillator between the high power source and the NFM device. Further, polarization conversion using Raman or Brillouin wavelength shifting is provided to optimize frequency conversion efficiency in the NFM device.

Abstract: A tunable microelectromechanical optical filter is placed in a linear laser cavity and is tilted at a large enough angle to prevent the unwanted reflections from coupling back to the mode of the cavity. Front and back mirrors form the cavity with a lens matching the mode of the gain media to that of the tuning element. The gain media can be a semiconductor, a solid state crystal or a fiber based region. In another preferred embodiment, the invention includes a ring cavity geometry with clockwise laser oscillation. In this case, the surface of the tunable microelectromechanical filter can be perpendicular to the direction of laser oscillation since the unwanted reflection may be prevented from coupling to the cavity mode by the action of an isolator.

Abstract: A frequency conversion system includes at least one source providing a first near-IR wavelength output including a gain medium for providing high power amplification, such as double clad fiber amplifier, a double clad fiber laser or a semiconductor tapered amplifier to enhance the power output level of the near-IR wavelength output. The NFM device may be a difference frequency mixing (DFM) device or an optical parametric oscillation (OPO) device. Pump powers are gain enhanced by the addition of a rare earth amplifier or oscillator, or a Ra-man/Brillouin amplifier or oscillator between the high power source and the NFM device.

Abstract: A gain module is provided for a master oscillator pumped amplifier system of a solid state laser including a ceramic housing supporting a Nd:YAG lasing slab therein. The slab is fixed relative to the housing by a pair of oppositely disposed compliant and optically transmissive securing members fictionally wedged between the housing and the lasing slab. A plurality of fluid passages are formed in the housing so as to communicate with the lasing slab. As fluid overflows the slab, the compliant securing members prevent the slab from vibrating. Preferably, the securing members are formed as U-shaped polycarbonate bars frictionally engaging the slab on a first surface and positionally adjustable driver bars coupled to the housing via a set screw block on a second surface.

Abstract: In a second harmonic, single-mode laser having a resonator including a Cr-doped fluoride laser crystal, first and second wavelength-selecting elements and a nonlinear optical crystal between a pair of laser mirrors, a wavelength-selecting width of the first wavelength-selecting element is {fraction (1/30)} or less of that of the second wavelength-selecting element, the first wavelength-selecting element is provided with a reflection coating having a reflectivity of 10-30% to the oscillated laser beam, such that the wavelength selection width of the first wavelength-selecting element is 0.02-0.03 nm, a wavelength interval in the oscillation wavelength range of the first wavelength-selecting element is 0.8-1.3 nm, and a wavelength selection width of the second wavelength-selecting element is 1.0-1.6 nm.

Abstract: Dual-cavity resonators that may be optimized for multiple functions (operating modes). The dual-cavity resonators provide a first set of operating modes that exhibits low repetition rates (5-20 Hz), high energy per pulse, and long, pulse-width, and a second set of operating modes that exhibits high repetition rates (100-2000 Hz), low energy per pulse, and short pulse-width.

Abstract: An unproved optical bench for use in an optical system, such as a miniaturized laser transmitter, or the like. The optical bench has a housing with a plurality of V-shaped grooves formed therein. Optical elements of the optical system in which the optical bench is used are secured, such as by bonding, in the plurality of V-shaped grooves. The optical bench thus rigidly mounts the optical elements of the optical system to produce a compact and lightweight structure that is relatively insensitive to environmental extremes.

Abstract: An apparatus and method are provided for bandwidth narrowing of an excimer laser to &Dgr;&lgr;≈6 pm or less with high spectral purity and minimized output power loss. Output stability with respect to pulse energy, beam pointing, beam size and beam output location is also provided. The excimer laser includes an active laser medium for generating a spectral beam at an original wavelength, means for selecting and narrowing the broadband output spectrum of the excimer laser, a resonator having at least one highly reflecting surface, and an output coupler. Means for adapting a divergence of the resonating band within the resonator is further included in the apparatus of the invention. The divergence adapting causes the spectral purity to improve by between 20% and 50% and the output power to reduce by less than 10%. A method according to the invention includes selecting and aligning the divergence adapting means.

Abstract: An improved tunable diode laser is capable of fast digital line selection over a broad wavelength spectrum, and uses no moving parts. A focusing element, such as a mirror or a lens, used in combination with a micromirror array serves as the retroreflector in a typical Littman-Metcalf laser cavity. This configuration provides arbitrary, simultaneous, and/or sequential line selection capability over a very broad wavelength range. The use of an individually-controllable micromirror array eliminates the high precision mechanical motion of a grating element and improves the overall durability and ruggedness of the device. The present invention can be integrated into any diode laser and has significant application in spectroscopy.

Abstract: A laser includes an asymmetrical laser-resonator formed between a concave maximally-reflecting mirror and a plane output-coupling mirror. The laser-resonator includes a transversely optically-pumped gain-medium rod asymmetrically located in the laser-resonator closer to the output-coupling mirror than to the maximally-reflecting mirror. Components of the laser-resonator are configured, dependent upon the thermal-lensing coefficient of the gain-medium and optical pumping power, such that the laser-resonator operates as a stable resonator generating a multimode circulating laser-beam. The beam has a width at the maximally-reflecting mirror greater than its width at the output-coupling mirror for reducing laser-damage to the maximally-reflecting mirror. The beam symmetrically fills the gain-medium thereby providing optimum laser-energy extraction from the gain-medium.

Abstract: The invention refers to a laser having first and second reflecting elements (3, 4) defining a laser cavity; a laser microchip (1) provided in the laser cavity to generate laser radiation of a fundamental wavelength; and a quasi-phase matching non-linear optical element (2) provided in the laser cavity to receive said laser radiation of the fundamental wavelength from the laser microchip (1) and to emit frequency doubled laser radiation (SH) of a wavelength half as long as the fundamental wavelength.

Abstract: A narrow band, high power and coherent source of red light in the red (600-650 nm) spectral region is disclosed. The red light source comprises a first optical source for emitting a first light beam at a first wavelength, a second optical source for emitting a second light beam at a second wavelength, a combiner for combining the first and second light beams to produce a combined beam, and a nonlinear crystal responsive to the combined beam for producing a sum frequency light beam of red light.

Abstract: A pulsed laser preferably a tunable laser having a narrow band width is provided which has a high conversion efficiency at a high repetition rate. The laser includes a diffraction grating located in the laser's optical cavity. The optical cavity is defined by a mirror and diffraction grating or two mirrors with a diffraction grating therebetween. A tunable laser material is located within the optical cavity between the mirror and the diffraction grating. Desirably the diffraction grating is movably mounted within the optical cavity so that a beam of a presected wave length diffracted by the grating can be directed across the laser material. Optionally where two mirrors define the optical cavity, one of the mirrors or the grating or both can be movably mounted within the optical cavity. Preferable the movable grating and the movable mirror are rotatably mounted.

Abstract: A tunable laser incorporating an N1×N2 chirped waveguide grating router that has N1N2 wavelengths, accessible in a digitally rapid manner, and using only N1+N2+1 semiconductor optical amplifiers. Through the use of chirp, free-spectral range of the router can be significantly less than the channel span. The exemplary laser has N1=5, N2=8, a channel spacing of 100 GHz, and the router free-spectral range is only 20 channels.

Abstract: The free spectral range dependent on the length of an oscillator is put in a relation of integral times with respect to the free spectral range dependent on the length of at least a nonlinear optical crystal or a wavelength selection SHG output element. Thereby, reduced noise in the output of a second-harmonic generator is intended.

Abstract: A fourth harmonic frequency generating method and apparatus is provided. The system includes within the optical cavity an active laser medium, a second harmonic generator for generating second harmonic frequency of the fundamental frequency emitted by the laser. The fundamental beam is directed to a second harmonic generation crystal where a portion of the fundamental beam is converted to a second harmonic beam. Both the second harmonic and unconverted fundamental beams are directed back across the second harmonic generator by reflective surfaces for a second pass prior to any conversion of second harmonic beam to a higher harmonic beam. Preferably the second harmonic and fundamental beams are reflected by one of the laser cavity reflective surfaces for the second pass. Optionally, there can be separate reflective surfaces to reflect each of the fundamental and second harmonic beams.

Abstract: A compact solid-state laser has its cavity formed by the reflection surface of a gain crystal and the reflection surface of a chirped mirror. Pumping light is incident to the cavity through the reflection surface of the gain crystal or the chirped mirror, from which the laser output is led out. Forming of the cavity solely by the gain crystal and chirped mirror enables the elimination of additional component parts for the compensation of dispersion, thereby making the entire laser system compact, and consequently permitting an increase in the repetition frequency.

Abstract: A lens duct is used for pump delivery and the laser beam is accessed through an additional component called the intermediate beam extractor which can be implemented as part of the gain element, part of the lens duct or a separate component entirely.

Abstract: In a laser such as a mode-locked or Q-switched laser, one of the resonator reflectors comprises a switchable Faraday rotator mirror coupled to a switchable magnetic field source. The operation of the laser is therefore controlled by the application of the magnetic field to the Faraday rotator device. When no magnetic field is applied, the device behaves as an isolator and thereby breaks the signal path between the resonator reflectors. When a saturation magnetic field is applied, the reflectors, disposed on opposite sides of the optical gain medium, thereby form a cavity such that lasing will occur. The device may be formed of discrete components or fabricated as an integrated optical device.

Abstract: A high-power external cavity laser source is described. The laser source includes a free space external cavity. At least two multimode optical gain elements are positioned in the cavity. Each gain element generates multimode optical radiation having one of at least a first and a second wavelength and one of at least a first and a second free space optical path, respectively. In another embodiment, at least two optical fiber gain media are positioned in at least two respective free space optical paths and each gain media generates optical radiation having one of at least a first and a second wavelength, respectively. An optical element is positioned in the cavity such that its focal plane is substantially located at the at least two optical gain elements and such that it intercepts the at least two respective free space optical paths. A dispersive element is positioned in the at least two optical paths. A partially reflecting element is also positioned in the at least two optical paths.

Abstract: The invention comprises a liquid crystal Fabry-Perot interferometer tuned external cavity semiconductor laser. The laser oscillates single mode at a discrete set of wavelengths defined by the transmission of an intracavity static Fabry-Perot etalon. The liquid crystal Fabry-Perot interferometer has a free spectral range larger than the gain bandwidth of the laser amplifier so that it selects only one transmission wavelength. Its resolution bandwidth is much greater than the free spectral range of the external cavity. The static intracavity etalon's free spectral range is greater than the resolution bandwidth of the liquid crystal Fabry-Perot interferometer. The static etalon maintains a single mode oscillation by providing a filter narrow enough to select only one external cavity mode.

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 speckle reduction system divides pulses of coherent radiation into successions of temporally separated and spatially aberrated pulselets. One or more beamsplitters divide the pulses into the successions of pulselets that are circulated through delay lines. Spatial aberrators located along the delay lines modify wavefront shapes of the pulselets. Together, the temporal separation and spatial aberration of the pulselets produce a succession of different speckle patterns that can be averaged together within the integration interval of a detector to reduce speckle contrast.

Abstract: A smart laser having automatic computer control of pulse energy, wavelength and bandwidth using feedback signals from a wavemeter. Pulse energy is controlled by controlling discharge voltage. Wavelength is controlled by very fine and rapid positioning of an RMAX mirror in a line narrowing module. Bandwidth is controller by adjusting the curvature of a grating in the line narrowing module. Preferred embodiments include automatic feedback control of horizontal and vertical beam profile by automatic adjustment of a prism plate on which beam expander prisms are located and automatic adjustment of the RMAX tilt. Other preferred embodiments include automatic adjustment of the horizontal position of the laser chamber within the resonance cavity. In preferred embodiments, feedback signals from a wavelength monitor are used to position the RMAX mirror. In other preferred embodiments a separate laser beam reflected off the RMAX mirror on to a photodiode array is used to position the mirror.

Abstract: The present invention also features an external cavity laser source that includes a free space external cavity comprising a laser array, an optical element, a dispersive element, and a partially reflecting element. The laser array comprises at least two optical gain elements where each of the at least two optical gain elements generate optical radiation having a unique wavelength. The optical element has a focal plane and is positioned to substantially place the focal plane at the at least two optical gain elements and to intercept the generated optical radiation. The dispersive element is positioned substantially at the focal plane of the optical element. The partially reflecting element is positioned to intercept radiation from the dispersive element. The partially reflecting element and the gain elements together forming the free space laser cavity that defines the at least first and second wavelength.

Abstract: Abstract of the Disclosure A solid-state laser apparatus has a solid-state laser medium inside a resonator. A pump light source such as a semiconductor laser apparatus generates pump light, and an optical system focuses the pump light on the solid-stated laser medium such that its distribution is not only inside but also at least in part outside the resonator mode in the solid-state laser medium, say, over more than 50% of the total length of the solid-state laser medium.

Abstract: A gas laser, in particular an axial-flow CO2 gas laser, includes a resonator having a folded beam path in a first folding plane and in a second folding plane inclined at 45° thereto. At least one Z-fold of the beam path is provided in the first folding plane and at least one U-fold of the beam path is provided in the second folding plane.

Abstract: A Fabry-Perot etalon filter for use as a telescope filter and method for making such etalons is disclosed. Particularly, an air-gap etalon having a first etalon plate and a second etalon plate being separated by a plurality of spacers. Said separation defining a gap. Said spacers being cut from a small area of a spacer substrate which has been formed to a high degree of uniformity. As a result, the spacers have a high degree of uniform flatness, parallelism, and thickness. By optically contacting the spacers to the etalon plates, the precision of the spacers is transferred to the etalon gap. For etalons where an obstructed central aperture is not critical, a centrally mounted spacer may be used to increase etalon gap uniformity across the entire surface of the etalon plates. Also, where a clear central aperture is needed, large peripherally mounted spacers may be used to establish high gap uniformity across the etalon. A method of constructing etalons is disclosed.

Abstract: In an optical system having at least one optical part other than mirrors, for example, a wavelength conversion optical system which uses an external resonator, an optical system which is capable of solving the problem of transverse mode generation due to the existence of scattering matter and the optical crystal used and capable of supplying a stable output (stable wavelength conversion output) is provided. At least at one point in a stable resonator having optical parts (optical crystal) other than mirrors, an aperture having a circular hole with a diameter 1 to 10 times the diameter of a beam at the aperture, a slit having a width 1 to 10 times the diameter of the beam, or an aperture of an arbitrary shape having an edge is located, or a knife edge having an linear or curved edge is Located so that the nearest distance between the edge and the beam is 1 to 10 times the radius of the beam from the center of the beam.

Abstract: A dual discharge tube excimer laser is provided. An oscillator having a first discharge tube generates a laser beam having a cross-sectional shape as initially defined by the first discharge tube. The oscillator selects a bandwidth of the laser beam and maintains the cross-sectional shape of the laser beam within the oscillator and as it exits the oscillator. The laser beam exiting the oscillator is amplified by one pass through the first discharge tube and two passes through a second discharge tube.

Abstract: A VCSEL comprises separate current and optical guides that provide unique forms of drive current and transverse mode confinement, respectively. In one embodiment, the optical guide comprises an intracavity high refractive index mesa disposed transverse to the cavity resonator axis and a multi-layered dielectric (i.e., non-epitaxial) mirror overlaying the mesa. In another embodiment, the current guide comprises an annular first electrode which laterally surrounds the mesa but has an inside diameter which is greater than that of an ion-implantation-defined current aperture. The current guide causes current to flow laterally from the first electrode along a first path segment which is essentially perpendicular to the resonator axis, then vertically from the first segment along a second path segment essentially parallel to that axis, and finally through the current aperture and the active region to a second electrode.

Abstract: The invention provides a device with an improved tunable laser structure, the structure useful with surface emitting lasers and capable of exhibiting desirable latchability. The tunable laser of the invention contains a laser structure having a lower reflector, an active laser region, and an upper reflector. The upper reflector contains a non-moveable reflector portion located adjacent the active laser region and a moveable reflector portion located a spaced distance from the non-moveable reflector portion. A magnetic material is located either on a surface of the moveable reflector portion or on a surface in contact with the moveable reflector portion, and a programmable magnet is located near the magnetic material, the magnet capable of inducing controlled movement of the magnetic material. This movement in turn induces movement of the moveable reflector portion such that the spaced distance between the moveable reflector portion and the non-moveable reflector portion is capable of being adjusted.

Abstract: A new class of vertical-cavity lasers (VCLs) is disclosed. Conventional VCLs contain an active region enclosed by Bragg-mirror stacks of 30-100 quarter-wave layers. The new VCLs can be fabricated without Bragg mirrors by replacing them with efficient diffractive (guided-mode resonance (GMR)) mirrors with much fewer layers, for example, two or three layers. This application provides optical power flow across and along the VCL gain region, thereby greatly increasing the laser efficiency and reducing the threshold mirror reflectance needed for lasing, relative to conventional VCLs. Theoretical and experimental results show that GMR mirrors exhibit high reflectance (theoretically, 100%; experimentally, in excess of 90%) in a narrow spectral band with well-defined polarization states. When incorporated in VCLs, the GMR mirrors yield single-mode, narrow-line, highly-polarized output light. The GMR-VCL is independent of any particular material system.

Abstract: A tunable optical wavelength selective filter is constituted by a dynamic holographic diffraction element (3) in combination with a fixed diffraction grating or hologram (2). The dynamic diffraction element (3) is preferably implemented as an electronically controlled image displayed on a pixelated spatial light modulator and in particular a spatial light modulating using photo-electronic integrated circuits fabricated using silicon VLSI technology and integrated with ferro-electric liquid crystals. Amongst other uses the filter can be implemented to form a digitally tunable laser.

Abstract: An intracavity frequency-doubled laser has a standing-wave resonator including a gain medium and an optically-nonlinear crystal. The optically-nonlinear crystal has a large walkoff-angle between the fundamental laser-beam and the frequency-doubled beam created by passage of the fundamental laser-beam through the crystal. The optically-nonlinear crystal is arranged such that the walkoff-angle provides for lateral, spatial separation of a fundamental and a corresponding frequency-doubled beam outside the crystal, and for separation of counterpropagating frequency-doubled beams from each other. The spatial separation of the counterpropagating frequency-doubled beams reduces amplitude fluctuation caused by interference between the beams. A physical stop is used to prevent one of the frequency-doubled beams from entering the gain medium. This prevents that beam from spuriously pumping the gain medium and thus serves to further reduce amplitude fluctuation.

Abstract: A durable etalon based laser output coupler. The output coupler is especially useful for ultraviolet lasers such as an ArF excimer laser or an F.sub.2 laser. The principal elements of the etalon based output coupler are two prisms aligned so that a first surface of one of the two prisms is parallel to a first surface of the other prism. The first of the two prisms have a second surface forming an angle with a beam from a laser cavity equal to or approximately equal to Brewster's angle. The second of the two prisms has a second surface forming an angle with the coupler exit beam equal to or approximately equal to Brewster's angle. Preferably, the prisms are comprised of CaF.sub.2 and surrounded by nitrogen at about one atmosphere. Assuming the laser beam is at a wavelength of 193 nm (for ArF excimer laser), Brewster's angle is about 57 degrees and each of the first and second surfaces define an apex angle of about 34 degrees.

Abstract: Optically pumped laser wherein the light beam P, which comes, for example, via light conductors 4 from the pump light source 200, is split into two component beams (T1, T2), for example, by a beam splitter 2. The two component beams (T1, T2) are directed to the laser medium 1 separately, for example, from both ends, or at an angle onto one end. Laser crystals such as Nd:YVO.sub.4, Nd:YLF, Nd:LSB or Nd:YAP having polarization-dependent absorption are especially suitable for pumping.

Abstract: This invention discloses an optical resonator (24) including at least one spiral optical element (44) operative to change the angular phase distribution of modes in the optical resonator (24), thereby to generally eliminate undesirable modes.

Abstract: A solid state laser comprises a cavity resonator in the form of a generally cylindrical body and, located within the resonator, an active region which generates lasing light when suitably pumped. The resonator has a relatively high effective refractive index (n>2 and typically n>3) is sufficiently deformed from circularity so as to support at least one librational mode (e.g., a V-shaped or a bow-tie mode, the latter being presently preferred for generating relatively high power, directional outputs). Specifically described is a Group III-V compound semiconductor, quantum cascade (QC), micro-cylinder laser in which the resonator has a flattened quadrupolar deformation from circularity. This laser exhibits both a highly directional output emission and a three-order of magnitude increase in optical output power compared to conventional semiconductor micro-cylinder QC lasers having circularly symmetric resonators.

Abstract: The present invention relates to a method and a device for purifying methane gas in a Raman cell (20). When pumped laser light having a high power passes through the Raman cell containing methane gas, a portion of the methane can be decomposed, and then highly reactive methyl radicals are formed. They can react with each other and as time passes form organic compounds, which are deposited on the inner side of the windows (22a, 22b) of the Raman cell. A trap (26) comprising calcium grains (27), which absorb the methyl radicals, is introduced in the Raman cell (20). The methane gas, which comprises a small content of methyl radicals, is made to come in contact with the calcium grains (27), whereby a reaction occurs between the methyl radicals and the calcium grains, so that calcium carbide and calcium hydride are formed. The methane gas is driven around in the Raman cell (20) and through the trap (26) by means of a compressor wheel (28) driven by a motor (29c).

Abstract: A system for providing support for the movement of a laser chamber of a laser system during the installation and removal of the laser chamber from the laser system housing. The system includes a rail assembly that is retractable and extendible from the laser system housing and provides support for moving the laser chamber between an operating position within the housing and a position outside of the housing for removal. The rail assembly is retractable to reside within the housing when not in use. The system may also include at least one actuator for controlling the movement of the laser chamber in a direction having a vertical component. Actuator types that may be used include rotary, piston cylinder, hydraulic, pneumatic, and/or electrical mechanical. One type of rail assembly includes opposing rail structures that retract and extend by moving laterally out from the housing or by pivoting out from the housing. The system may be implemented with a gas laser system such as an excimer laser system.

Abstract: A solid-state laser apparatus and method in which a laser crystal and a non-linear optical crystal are connected and unitarily combined by a spacer. An optical resonator is constructed between both ends thereof. An optical cavity where the laser light passes through is formed between the laser crystal and the non-linear optical crystal. An end surface of the laser crystal is treated by optical polishing to form a laser resonator in the optical cavity. Alignment between the crystal becomes unnecessary, and subsequent assembling is thus simplified. Fresnel reflection occurs on the end surface of a laser crystal treated only by the optical polishing due to an index of refraction coefficient difference.

Abstract: An optically-pumped laser comprises a laser cavity, a solid-state gain medium and an optically transparent heat sink (OTH) situated within the laser cavity. The gain medium and OTH are thermally coupled and at least one of the solid-state gain medium and the OTH has an etalon structure thereby improving laser efficiency. The OTH advantageously provides effective heat transfer and permits higher average power operation, particularly for thin solid-state laser materials. A metallic heat sink may be thermally coupled to the OTH to improve heat transfer. In some embodiments, the laser is end-pumped with optical pump radiation through the OTH. A second intracavity OTH may be thermally coupled to the gain medium opposite the first OTH to provide longitudinal heat transfer in both directions. A frequency-converted laser may be provided by using a nonlinear material longitudinally cooled on each end by intracavity OTHs, at least one of which comprises an etalon structure.