Abstract: An F2-excimer laser has multiple closely-spaced spectral lines of interest around 157 nm, and one of the lines is selected by wavelength selection optics. The wavelength selection optics of a first preferred embodiment include a birefringent Brewster window enclosing the laser gas volume of the discharge chamber. The window preferably comprises MgF2 and is located at one end of the discharge chamber. One line is selected of the two when the optical thickness of the window is selected in coordination with rotatably adjustable, orthogonal refractive indices of the window. The transmissivity of the window is dependent on the orthogonal refractive indices and the optical thickness of the window. The wavelength selection optics of a second preferred embodiment include are at least partially within the laser active volume. In this way, line selection is performed in a manner which optimizes the combination of optical and discharge efficiency, resonator size and cost.

Abstract: A line narrowed laser system having a spatial filter to filter light at wavelengths greater and/or smaller than a desired range of wavelengths. The laser system is line narrowed with a line narrowing mechanism having a dispersive element which disperses laser light into wavelength dependent directions. By spatially filtering the resulting beam the bandwidth of the beam can be reduced substantially. There is also a reduction of beam energy as a result of the spatial filtering but this reduction is substantially less than some other known techniques for reducing bandwidths. A preferred spatial filter, for reducing the bandwidth of a line narrowed gas discharge laser, includes two cylindrical mirrors separated by a distance equal to their focal lengths with a slit aperture positioned at the common focal line.

Abstract: A semiconductor laser device having a chip electrode of a semiconductor laser is provided. The laser device includes a first electrode layer of a first material, and a second electrode layer of a second material. The second electrode layer has an opening corresponding to a light-emitting section of the laser, and is formed on a face of the first electrode layer. The first material of the first electrode layer is different than the second material of the second electrode layer.

Abstract: A narrow band molecular fluorine laser system includes an oscillator and an amplifier, wherein the oscillator produces a 157 nm beam having a linewidth less than 1 pm and the amplifier increases the power of the beam above a predetermined amount, such as more than one or several Watts. The oscillator includes a discharge chamber filled with a laser gas including molecular fluorine and a buffer gas, electrodes within the discharge chamber connected to a discharge circuit for energizing the molecular fluorine, and a resonator including the discharge chamber for generating a laser beam having a wavelength around 157 nm. Line-narrowing optics are included intra- and/or extra-resonator for reducing the linewidth of the laser beam to less than 1 pm. The amplifier may be the same or a different discharge chamber, and optical and/or electronic delays may be used for timing pulses from the oscillator to reach the amplifier at a maximum in the discharge current of the amplifier.

Abstract: Diamonds are marked by a laser beam having a characteristic that is changeable by positioning a selected aperture in the beam within a resonant cavity of a laser source. Guidelines are positioned in advance on the diamonds, and the marking is subsequently performed between the guidelines.

Abstract: Circuitry for controlling a diode optically coupled to an optical fiber suitable for transmitting digital light signals therethrough. The circuitry includes a temperature compensated driver when operating in the transmit mode and receiving circuitry for conditioning and amplifying electrical signals generated by the diode when it operates in a photodetection mode. A sweep circuit is provided for isolating amplifiers in the receiving circuitry and for discharging residual charge left in the diode during the transmission mode thereby reducing the signal-to-noise ratio.

Abstract: A gas laser (1) has an optics system and a mode-masking diaphragm in the beam guiding chamber of the laser resonator. The optics system is adjustable between two settings in each of which any higher-order modes of the laser beam (3) are masked out. The Gaussian mode (9) can be generated in one of the two settings, and the ring mode (10) in the other setting. An appropriate control permits switching between Gaussian and ring modes depending upon the intended processing operation.

Abstract: A laser, including a grating structure consisting of two or more gratings generating a plurality of different wavelength peaks for reflection of optical radiation therefrom. The laser also includes a semiconductor device having a gain region which is operative to amplify the optical radiation, and a wavelength tunable filter (WTF) region which is adapted to filter the optical radiation. The device is optically coupled to the grating structure so as to define a laser cavity having a plurality of cavity modes. The cavity modes are selected by tuning a wavelength pass-band of the WTF region to overlap with one of the wavelength peaks of the grating structure.

Abstract: An apparatus and method for forming an aperture of a vertical cavity surface emitting laser (VCSEL) by selective oxidation, in which resonance peak variations during the formation of the aperture can be measured using an optical spectrum analyzer, so that the size of the aperture can be precisely adjusted. The aperture forming apparatus includes: a furnace having a first window and a second window for transmitting light, and a stage for supporting a wafer for the VCSEL with a pre-oxide layer where an aperture is to be formed; a light source placed outside the furnace, for emitting light through the first window onto the top of the wafer seated on the stage; and an optical spectrum analyzer for detecting the light intensity by receiving light reflecting from the top of the wafer for the VCSEL and passing through the second window.

Abstract: A method and a system for generating grating images with an improved speed is disclosed. The system utilizes a coherent light source for providing a coherent beam L, an exposure control device for controlling the exposure of the coherent beam L, a beam guiding device for controlling the pitch and the orientation of each grating, a symmetrical beam generating device for splitting the coherent beam L into two symmetrical coherent beams, a local scan device for allowing the two coherent beams to intersect and form a standing wave, at different position in a small local scan area in order to combine different gratings in the local scan area, a photosensitive material for recording the standing wave, and a supporting device for supporting and moving the photosensitive material so as to combine different local scan area, and obtain a large scale grating image.

Abstract: An apparatus and method of fabricating and operating a micro-electromechanical systems (MEMS) integrated optical structure is disclosed. Micro-optics is integrated with MEMS actuators to provide a building block for a micro-optical communication device. Such micro-optical communication device may realize a variety of optical communication systems including optical interconnects, laser communications, or fiber optic switches. In accordance with one aspect of the present invention, a micro-optical element such as a micro-lens is advantageously integrated with an actuator such as MEMS comb drive actuator to form a MEMS lens assembly. The MEMS lens assembly is further coupled to an optical source which may provide a MEMS integrated micro-optical communication device. This integration substantially obviates the generally needed external or manual positioning of the micro-optical element to align a light beam or an optical signal being emitted from the optical source.

Abstract: Phase masks which can be used to make both linear and curved gratings of single or multiple submicron pitches, with or without any abrupt quarter-wavelength shifts (or gradually varying finer phase shifts) simultaneously on the wafer/substrate. The phase masks are made using direct write electron or ion-beam lithography of two times the required submicron pitches of linear and curved gratings on commercially available &pgr; phase-shifting material on a quartz substrate and wet or dry etching of the &pgr; phase-shifting material. The phase masks can be used in connection with making multi-wavelength laser diode chips. The laser diodes have a ridge structure with metal shoulders on either side of the ridge. The laser diode chip, with different wavelength lasers, is bonded and interfaced to a novel microwave substrate that allows for high signal-to-noise ratio and low crosstalk. The substrate is packaged in a low loss rugged housing for WDM applications.

Abstract: A narrow band molecular fluorine laser system includes an oscillator and an amplifier, wherein the oscillator produces a 157 nm beam having a linewidth less than 1 pm and the amplifier increases the power of the beam above a predetermined amount, such as more than one or several Watts. The oscillator includes a discharge chamber filled with a laser gas including molecular fluorine and a buffer gas, electrodes within the discharge chamber connected to a discharge circuit for energizing the molecular fluorine, and a resonator including the discharge chamber for generating a laser beam having a wavelength around 157 nm. Line-narrowing optics are included intra- and/or extra-resonator for reducing the linewidth of the laser beam to less than 1 pm. The amplifier may be the same or a different discharge chamber, and optical and/or electronic delays may be used for timing pulses from the oscillator to reach the amplifier at a maximum in the discharge current of the amplifier.

Abstract: A technique for increasing the lifetime of optical components that are used in a laser for laser shock peening. The technique employs a properly sized iris or a gradient reflector within a laser oscillator to produce a single-transverse-mode laser beam. This technique eliminates hot spots that significantly reduce the lifetime of optical components. Utilization of the present invention can increase the lifetime of components by a factor of ten of their conventional lifetime.

Abstract: A line narrowed laser system having a spatial filter to filter light at wavelengths greater and/or smaller than a desired range of wavelengths. The laser system is line narrowed with a line narrowing mechanism having a dispersive element which disperses laser light into wavelength dependent directions. By spatially filtering the resulting beam the bandwidth of the beam can be reduced substantially. There is also a reduction of beam energy as a result of the spatial filtering but this reduction is substantially less than some other known techniques for reducing bandwidths. A preferred spatial filter, for reducing the bandwidth of a line narrowed gas discharge laser, includes two cylindrical mirrors separated by a distance equal to their focal lengths with a slit aperture positioned at the common focal line.

Abstract: The invention relates to a device (300) for tuning the wavelength of the light in an external cavity laser. The external cavity laser comprises an optically amplifying semiconductor chip (310), a first reflecting surface (312), an Anti-Reflection (AR) coated semiconductor chip facet (314), a diffraction grating (330) on which at least part of the beam originating from the AR coated semiconductor chip facet (314) is incident and diffracted back to the optically amplifying semiconductor chip (310), means (320) for collimating the light emitted from the AR coated semiconductor chip facet (314) towards the diffraction grating (330), and a movable part (360) by means of the movement of this said part the wavelength of the light can be tuned in the external cavity laser.

Abstract: An F2-excimer laser has multiple closely-spaced spectral lines of interest around 157 nm, and one of the lines is selected by wavelength selection optics. The wavelength selection optics of a first preferred embodiment include a birefringent Brewster window enclosing the laser gas volume of the discharge chamber. The window preferably comprises MgF2 and is located at one end of the discharge chamber. One line is selected of the two when the optical thickness of the window is selected in coordination with rotatably adjustable, orthogonal refractive indices of the window. The transmissivity of the window is dependent on the orthogonal refractive indices and the optical thickness of the window. The wavelength selection optics of a second preferred embodiment include are at least partially within the laser active volume. In this way, line selection is performed in a manner which optimizes the combination of optical and discharge efficiency, resonator size and cost.

Abstract: A cost-effective and accurate light source deice for use in an image forming apparatus and including semiconductor lasers is disclosed. The device needs only a minimum number of parts, obviates displacements during assembly, and allows collimator lenses to be adhered by photo-curable adhesive. Even when temperature around the device varies, the distance between the semiconductor lasers in a beam pitch direction varies little.

Abstract: A semiconductor-laser-pumped solid state laser includes a solid state laser medium doped with a rare earth element such as neodymium and a semiconductor laser which emits a pumping laser beam for pumping the solid state laser medium. A pumping light incident side end face of the solid state laser medium is fixed to a holder.

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: A power efficient continuous wave gas ion laser system, associated laser tube and method are described. The system uses a fixed electrical input power and a power factor corrected power supply producing an output voltage and an output current from the fixed input electrical power. A gas ion laser tube is configured for use in the system having a particular cavity length which is established as a distance between a first mirror and a second mirror for operation using the output voltage and the output current. The system may be configured to provide a light output power improvement of approximately thirty percent over prior laser systems. In one feature, a laser tube is configured for providing the improved light output power in a conventional laser head configuration such that the laser tube may directly replace laser tubes in prior installations. Existing and new laser installations may benefit.

Abstract: An exposure apparatus includes a first dispersing element for dispersing substantially parallel laser light, from a laser, with respect to the wavelength to provide light beams of wavelength units, a first optical system for collecting each light beam of a wavelength unit from the first dispersing element, a wavelength selecting device for passing a predetermined wavelength region of light, of the light beams of wavelength units each being collected by the first optical system, a second optical system for receiving the light from the wavelength selecting device and providing parallel light beams of wavelength units, and a second dispersing element for combining the parallel light beams of wavelength units from the second optical system, the second dispersing element having substantially the same angular dispersion as that of the first dispersing element and a direction of dispersion opposite to that of the first dispersing element.

Abstract: Diamonds are marked by a laser beam having a characteristic that is changeable by positioning a selected aperture in the beam within a resonant cavity of a laser source. Guidelines are positioned in advance on the diamonds, and the marking is subsequently performed between the guidelines.

Abstract: A wavelength stabilized laser system includes a laser that produces a laser light having an amplitude and a wavelength that varies as a function of a temperature of the laser. A temperature control device controls the temperature of the laser. A beam splitter deflects a portion of the laser light. A first detector receives the portion of the laser light from the beam splitter and provides a first signal representing the amplitude of the laser light. A filter has a gain that is a function of the wavelength of the laser light. The filter receives the laser light and outputs a filtered light having an amplitude that varies with the wavelength of the laser light. A second detector provides a second signal representing the amplitude of the filtered light. A sealed housing contains the laser, the first and second detectors and the filter. The housing has a window.

Abstract: A gas laser oscillator having at least three discharge tubes disposed along the optical axis, and a spacer having an opening centered on the optical axis. The spacer is disposed between a partially reflective mirror and the closest discharge tube. Further, the discharge tubes are disposed in series along the optical axis, and satisfy the following three formulas simultaneously: r1/r2>1.0  Formula 1 L2/(L1+L2)<0.85  Formula 2 r3/r2<1.4  Formula 3 where the sum of lengths of a pair of discharge tubes disposed at both ends in optical axis direction is L1, the inside diameter of these discharge tubes is r1, the sum of lengths of the other discharge tubes in the optical axis direction is L2, the inside diameter of these discharge tubes is r2, and the inside diameter of the opening of the spacer is r3.

Abstract: A superbroadband or multiwavelength laser transmitter source for wavelength-division multiplexing, two-wavelength interferometry, differential lidar and optical storage applications. Contrary to conventional tunable laser sources that can switch between different lasing wavelengths in a given wavelength band, the superbroadband laser simultaneously emits at multiple wavelengths. The basic idea of this system is to maintain simultaneous lasing operation in an optical active gain medium at different wavelengths. The system uses a novel dispersive cavity. By designing this cavity structure appropriately, the system creates its own microcavities each lasing at a different wavelength within the fluorescence band of the gain medium. Mode competition in the proposed cavity is absent and spectral range of simultaneous multi-frequency generation is considerably enhanced practically to the spectral width of the active media luminescence spectrum.

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 light-source device of a multi-beam scanning apparatus including a plurality of semiconductor lasers, collimator lenses provided for the semiconductor lasers and a holder member integrally holding the semiconductor lasers and the collimator lenses. The semiconductor lasers are pressed into the holder member, and the collimator lenses are bonded to the holder member with a part of each edge portion of the collimator lenses adjusted in position relative to said holder member. Positions of press-in portions of the holder member for the semiconductor lasers are relatively deviated and formed in such a manner that adhesive layers for bonding the holder member and the collimator lenses have a same thickness.

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 frequency-doubled diode pumped solid state laser with intracavity frequency doubling comprises a lasing solid state medium with suitable reflecting coats which makes up a component part of a resonator cavity. The solid state laser further comprises at least one pumped light source constructed as a laser diode and a frequency doubling nonlinear optical element in the form of a nonlinear crystal with suitable reflective coatings which forms a further component part of the resonator cavity. This resonator cavity is formed between reflective coatings of the solid state medium and of the element. The pumped radiation is transmitted to the lasing solid state medium through optical means. At least one aperture of a material with good thermal conductivity is provided at the element and/or at the lasing solid state medium. The frequency doubling optical element is designed for phase matching at a higher temperature than the surrounding temperature.

Abstract: A optical medium, such as an angled distributed reflector, e.g., an angular grating, or .alpha.-DFB laser diode or a waveguide wavelength selective filter, has a mean optical axis defining an optical cavity for substantially confined light propagation within the device. An angular grating is provided in at least a portion of the optical cavity forming a grating region permitting light to propagate along the optical cavity in two coupled waves or modes incident along the angular grating, a first incident propagating wave substantially parallel with respect to the mean optical axis and a second incident propagating wave at an angle with respect to the mean optical axis.

Abstract: An integrated laser/modulator ("ILM") operating with reduced chirping is formed on a single semiconductor substrate. A reduction in chirping and any resultant wavelength dispersion is realized by precisely controlling the length of a window region incorporated in the ILM in order to isolate the ILM's active regions from any residual reflections.

Abstract: A cost-effective and accurate light source deice for use in an image forming apparatus and including semiconductor lasers is disclosed. The device needs only a minimum number of parts, obviates displacements during assembly, and allows collimator lenses to be adhered by photo-curable adhesive. Even when temperature around the device varies, the distance between the semiconductor lasers in a beam pitch direction varies little.

Abstract: The laser beam produced by the improved precision laser maintains an axial stability of less than 20 micro-radians in the presence of ambient temperature changes and shock and vibration of as much as 100 g's, achieving a new milestone in stability. In the new laser one end of the resonator (7) is hard mounted to the laser bench (13) and the other end of the resonator is mounted to that laser bench by a flexure (17). The flexure is designed to resiliently yield in the presence of thermally induced strain on the bench while retaining sufficient stiffness against foreseeable shock and vibration.

Abstract: A vertical cavity surface emitting laser having intensity control for maintaining a constant proportional output under varying conditions of the laser. A tilted window is situated over the laser output to reflect a portion of the light to a photo detector area. Signals representing light on the photo detector go to a feedback circuit which controls the power output of the laser. The tilted window has a metallic coating for partial reflection and for minimizing polarization effects on reflected and transmitted light. The photo detector has an anti-reflective coating for likewise minimizing polarization effects of the detected light. The VCSEL and photo detector are situated on the same substrate.

Abstract: An improved excimer laser is disclosed. In one embodiment, the laser includes laser beam generating circuitry operable to generate a laser beam and a vessel enclosing the laser beam generating circuitry. The vessel contains a volume of gas conducive to the formation of the laser beam by the laser beam generating circuitry. The vessel has a wall with a beam aperture formed therein to permit the laser beam generated by the laser beam generating circuitry to pass through it. A window mount assembly is attached to the wall of the vessel. The window mount assembly encloses a beam cavity and has a window that transmits the laser beam. The window is positioned at a first, closed end of the beam cavity. The beam cavity has a second, open end adjoining the beam aperture formed in the vessel wall. The beam cavity has a lateral surface extending between the first and second ends. A plenum lies outside the beam cavity. A gas handling system extracts the gas from the vessel and provides the gas to the plenum.

Abstract: Laser systems, and optical elements for laser systems, are disclosed for providing a pumped laser light with improved output efficiency while having simple construction and simple alignment adjustment. A pump light flux from a diode pumping laser irradiates and thus pumps a solid-state laser crystal. The irradiation by the pump light flux is coaxial with an output laser beam produced by the laser crystal. The pump light flux is conducted by an optical element, preferably frustoconical in shape with an entrance face larger than an exit face, that functions as a light funnel. The entrance face is disposed proximal to the pumping laser 11, and the exit face is disposed proximally to the laser crystal 14. A portion of the pump light flux entering the entrance face passes through the optical element without being reflected by a side surface of the optical element. The remaining pump light flux reflects at least once by the side surface during passage through the optical element.

Abstract: An extended VCSEL structure formed of a first DBR mirror, an active region, a second DBR mirror as partial reflector, and an extended cavity provided by a transparent conductive substrate wafer fused onto the second DBR mirror. The transparent conductive substrate also serves as a convex mirror with a highly reflective dielectric coating to complete the extended cavity VCSEL structure. The use of the extended cavity makes high power single mode operation achievable because an extended cavity introduces high modal loss to the high order laser modes while supporting the lowest order single mode. The large active area allows high output power from the VCSEL.

Abstract: A laser system which generates short duration pulses, such as under five nanoseconds at an energy level of up to a few milli-Joules per pulse (mJ/p) with near diffraction limited beam quality. A laser crystal is pumped (excited) by diode lasers. A resonator having at least two mirror surfaces defines a beam path passing through the laser crystal. The beam path in the resonator is periodically blocked by a first optical shutter permitting pump energy to build up in the laser crystal, except for a short period near the end of each pumping period. While the first optical shutter is open a second optical shutter blocks the light in the resonator except for periodic short intervals, the intervals being spaced such that at least one light pulse traveling at the speed of light in the resonator is able to make a plurality of transits through the resonator, increasing in intensity by extracting energy from the excited laser crystal on each transit.

Abstract: The present invention relates to a vertical cavity surface emitting laser device comprising a plurality of semiconductor layers formed upon a substrate and capable of emitting a laser beam of a selected wavelength and a selected polarization, wherein said polarization is established by the presence of stress inducing elements disposed on said free surface of the laser device which induce a stress in the active layers of the laser device. The stress inducing elements are made of a material having a higher coefficient of thermal expansion than the material which comprises the surface layer of the laser device.

Abstract: In order to obtain a high-power laser beam with a high beam quality with use of a small-sized and low-cost apparatus, there has been disclosed a laser resonator which is constructed so as to produce a single high-order transverse mode laser beam, and a technique for converting the laser beam with a single high-order transverse mode into a laser beam with a high beam quality. The laser resonator is provided with a regulating plate of a high-order transverse mode which is constructed so as to produce a laser beam in a single high-order transverse mode. A phase adjusting plate inverts a phase for each region of the laser beam divided depending upon a lateral mode thereof to match the phase for each region of the laser beam, and subsequently, a traveling direction of the laser beam is changed for each position thereof by means of the first binary optics element, and further, the laser beam is converted into a parallel beam by means of the second binary optical element.

Abstract: In a passively mode-locked short pulse laser arrangement including a laser resonator to which a pump beam is supplied, a titanium-sapphire (Ti:S) laser crystal, an optical Kerr element formed by the laser crystal itself, and an aperture restricting the resonator laser beam, the aperture has an arcuate or polygonal shape for adaptation to the beam cross-section.

Abstract: A microlaser cavity including an entry mirror, an exit mirror (36), an active laser medium. Also included is a mechanism for selecting cavity transverse modes when the cavity is pumped, in order to enable oscillation of one or several cavity transverse modes and to prevent oscillation of other cavity transverse modes.

Abstract: A laser system is provided for supplying high power, stable light intensity via an aperture limited delivery system to an application requiring continuous light output intensity in spite of the laser source being subjected optical feedback noise caused by external system and delivery system perturbations that cause fluctuation in laser source power intensity. Non-stable light intensity in the output is due to environmental temperature changes, and phase and amplitude changes caused by system induced perturbations such as by movement of the aperture limited delivery system and optical artifacts of the optical elements, comprising the aperture limited delivery system, introducing noise into the feedback in the laser system changing the output intensity pattern of the delivered power beam. This can be substantially remedied by the employing a monolithic, multiple, independent single mode laser source which is substantially unaffected by this noise.

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 diode pumped laser includes a resonator mirror and an output coupler, defining a laser resonator with a resonator optical axis. A strong thermal lens gain medium with a TEM.sub.00 mode diameter is mounted in the resonator along the resonator optical axis. The dopant level of the gain medium is in the range of 0.01 to less than 0.5 percent. A diode pump source supplies a pump beam to the gain medium in the laser resonator, and produces an output beam with a diameter larger than the TEM.sub.00 mode diameter to reduce thermal birefringence. A power source supplies power to the diode pump source. A polarizing element can be positioned in the resonator, along with a aperture stop The laser operates well over a large range of pump powers. Its slope efficiency in the TEM.sub.00 mode is greater than 40%, with an overall efficiency greater than 25%. One of the gain mediums used is Nd:YVO.sub.4. This material exhibits high gain and a short upper state lifetime.

Abstract: A surgical laser system is provided with improvements to allow it to operate at higher power levels without beam divergence. The improvements include a beam expansion telescope in the optical path of the beam and modifications to the optical cavity and the lasing medium. The modifications include imposing a negative curvature on one or both ends of the rod, configuring the optical cavity as a positive-branch unstable resonator, and providing at least one intra-cavity shutter.

Abstract: An excimer laser having reduced spectral bandwidth variation is provided. The laser has an assembly of components comprising a beam expander having at least two prisms that reduces the spectral bandwidth of the laser beam that is passed through the assembly. At least one of the prisms of the beam expander is made of a thermally stable material, wherein the material has an coefficient of absorption of no more than about 0.1 percent/cm for light having the desired wavelength, a rate of change of refractive index with temperature of no more than about 2.3.times.10.sup.-6 .degree.C..sup.-1, a thermal conductivity of at least about 9.71 W/m-.degree.C. at 20 deg C., and/or a coefficient of thermal expansion of at least about 9.times.10.sup.-6 (deg C.).sup.-1. In a preferred embodiment, the stability of beam profile is improved, the variation in spectral bandwidth of the beam from the laser is reduced, the spectral bandwidth itself is also reduced, and the laser exhibits greater voltage stability.

Abstract: An optic cell 20 for use in the cavity of a high-power laser comprises an optic housing 22 which defines a first laser beam aperture 26. An optic element 32 such as a mirror or lens is disposed within the optic housing. A first indium layer 30 is between and in abutting contact with the optic housing and the optic element. An optic cover 40 defines a second laser beam aperture 46 therethrough substantially in alignment with the first laser beam aperture to form a window 47 of the optic element through which a laser beam passes. A second indium layer 48 is between and in abutting contact with the optic element and the optic cover. The optic housing and the optic cover are typically formed of aluminum or copper to passively cool the optic element.

Abstract: An alignment cross hair apparatus for partially eclipsing a laser beam includes a laser generator that emits a laser beam. A frame includes a pair of members that cross one another at an intersection within the frame. The frame is attachable to the laser generator in such a manner that the intersection of the members is within the laser beam so that the laser beam is partially eclipsed by the pair of members.