Abstract: External Cavity Laser An external cavity laser comprising first and second feedback means with an optical gain medium (2) therebetween, one of the feedback means is provided by a grating (4) formed in a silicon waveguide and the other feedback means is provided by a reflective back facet (2B) of the optical gain medium (2). The output wavelength of the laser, at a given temperature, can thus be determined during its manufacture and the laser can be made by mass production techniques. The grating (4) may be thermally isolated to obviate the need for temperature control means (6) to control the temperature of the grating (4). An array of lasers may be provided on a single chip.

Abstract: A laser apparatus includes a laser resonator having a first reflective surface and a second reflective surface, the laser resonator further including a laser medium disposed between the first reflective surface and the second reflective surface for processing light reflected from the first and second reflective surfaces to output a laser beam to be resonated, and a resonator loss varying unit disposed between the first reflective surface and the second reflective surface of the laser resonator, the resonator loss varying unit being capable of switching a state thereof between a first state having a resonance frequency substantially coinciding with one of frequencies at which laser oscillation of the laser resonator is possible and a second state having the resonance frequency shifted to the value that is substantially different from any one of the frequencies at which laser oscillation of the laser resonator is possible to vary a loss of the laser resonator.

Abstract: A current driver circuit for a vertical cavity surface emitting laser (VCSEL), flip-chip bonded to a CMOS device. In a preferred embodiment, the circuit includes only two transistors. Specifically, a P-channel metal-oxide semiconductor (PMOS) source supplies a current under the control of a tuning voltage (Vtune) while an N-channel metal-oxide semiconductor (NMOS) transistor acts as a high-speed current shunt that modulates the current flowing through the VCSEL, and hence its emitted power.

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

Abstract: In a laser-diode-pumped solid state laser, a solid laser crystal is pumped by a pumping laser beam emitted from a laser diode and a harmonic of light emitted from the pumped solid laser crystal is caused to make laser oscillation by a resonator structure containing therein a nonlinear optical crystal. The electric current to be poured into the laser diode is controlled so that the pumping laser beam emitted from the laser diode is kept at an output level at which the pumping laser beam cannot cause the harmonic of light emitted from the solid laser crystal to make laser oscillation though pumping the solid laser crystal.

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: A variable wavelength laser light source to improve the resolution of the outgoing light and output only pure laser light without the natural emitted light has an optical amplification element (laser) 11, a first optical reflector 12 at one end surface 11a of the optical amplification element 11, and a wavelength selection element (diffraction grating) 13 at the other end surface 11b of the optical amplification element 11 which selects and outputs the desired wavelength light emitted by the optical amplification element 11. A second optical reflector 14 receives the outgoing light from the wavelength selection element 13 to form the optical resonator with the first optical reflector 12. A first rotating mechanism 15 rotates the second optical reflector 14 around its axis, and a second rotating mechanism 16 connected to the first rotating mechanism 15 rotates the second optical reflector 14 around a second axis 16a remote from the second optical reflector 14 by rotating the first rotating mechanism.

Abstract: A second harmonic generator comprising a semiconductor laser as an excitation light source and a resonator having a solid laser crystal excited by the excitation light source, a control element for controlling the wavelength of a first oscillation wave generated from the solid laser crystal and a nonlinear crystal for wavelength converting the first oscillation wave as a fundamental wave into a second harmonic wave as a second oscillation wave, wherein the components of the resonator are arranged in the order of a first laser mirror, solid laser crystal, wavelength control element, nonlinear crystal and second laser mirror from the input side of the excitation light.

Abstract: A solid state laser includes a resonator, a solid laser crystal disposed in the resonator, a pumping source for pumping the laser crystal, a pair of .lambda./4 plates which is disposed in the resonator with the laser crystal intervening therebetween and makes an oscillation beam of a twisted mode, and a polarization control element which is disposed in the resonator and sets the linear polarization of the solid state laser beam in a predetermined direction. The solid laser crystal is a birefringent crystal and an optical axis of the birefringence of the solid laser crystal is oriented in the direction of the linear polarization of the solid state laser beam set by the polarization control element.

Abstract: The invention relates to a laser light source having a broadband-amplifying and narrowband-tunable active medium, which involves an uncomplicated arrangement and is remarkable for the specific suppression of the broadband spontaneous emission and the side modes as well as for its optical stability.

Abstract: A structure for providing direct feedback of power emitted by a surface emitting light emitting device and the subsequent optical power control of the device is disclosed. In a preferred embodiment, an array of vertical cavity surface emitting lasers emit light having a wavelength which is partially detected by an array of photodetectors. The semi-transparent photodetectors array has an absorption coefficient which is relatively small at the wavelength of light emitted by the lasers. Most of the emitted light will be transmitted through the detectors while a small insignificant fraction in magnitude is absorbed and converted to photocurrent for monitoring the output power of the devices. The structure of the device of the present disclosure is simple, readily fabricated through uncomplicated techniques and of materials which do not effect the beam characteristics of the surface emitting devices.

Abstract: The present invention describes the use of a pair of acoustooptic devices in a laser or other optical resonator to produce a wavelength-dependent deflection of the light without incurring a net frequency shift. This permits rapid electronic tuning of the resonator wavelength, as well as rapid electronic variation of cavity loss, out-coupling fraction, and round-trip phase shift. The dispersive quality of acoustooptic devices in transmission is utilized as a reflection grating substitute. Two mirrors, one an output coupler, a gain medium and two acoustooptic devices arranged for maximum efficiency such that the incident and diffracted beams are approximately at the Bragg angle for each acoustooptic device permit the laser wavelength to be determined by the acoustic frequency.

Abstract: A solid state laser beam generating system includes a solid state laser which produces a laser beam having a wavelength outside the eyesafe range of 1.5 .mu.m to 1.8 .mu.m. A converter including a non-linear structure is used to convert the laser beam to a beam having a wavelength within the eyesafe range. The non-linear structure has three defined principal axes and the input laser beam to the structure travels in a direction offset from one of the principal axes by an angle greater than 2.degree..

Abstract: A line narrowed laser having a grating based line narrowing module, etalon-based line narrowing output coupler and a technique for tuning the laser. The etalon based output coupler is adjusted to preferentially reflect light at or near the spectral maximum produced by the grating. Substantial improvement in line narrowing results from the amplification in the laser resonance chamber of light at or near the grating spectral maximum which is preferentially reflected by the etalon based output coupler. Several preferred methods are disclosed for tuning the etalon based output coupler to match the wavelength selected by the grating based line narrowing module.

Abstract: A solid-state laser system for producing high output power and which is packaged in a small, cylindrical housing is set forth. The system includes a plurality of optical energy sources which emit energy that is absorbed by a solid-state laser medium that is configured as a rod. The solid-state laser medium has a central axis, first and second end surfaces, and outer surface between the end surfaces upon which the energy emitted from the optical energy sources is incident. The energy power sources are typically semiconductor laser diode arrays. The laser diode arrays are positioned adjacent to the cylindrical outer surface of the laser medium and usually extend along a substantial portion of the entire length of the outer surface. The system also includes first and second mirrors which are substantially aligned with the central axis of the laser medium for producing laser resonation through the first and second end surfaces of the laser medium.

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 microchip laser is formed from at least one portion of laser material and at least one nonlinear crystal. The laser material and nonlinear crystal are in physical contact with each other and an angled surface of either the laser material or the nonlinear crystal forms an air-spaced etalon between the laser material and the nonlinear crystal. The axis of the microchip laser passes through the etalon formed between the laser material and the nonlinear crystal. The etalon in the laser cavity produces a single mode output. Additionally, the nonlinear crystal within the cavity may operate, in conjunction with a polarization dependent gain cross-section in the laser material, as a birefringent filter to reduce the bandwidth of laser emission from a broadband active laser material.

Abstract: The invention relates to a microlaser cavity (10) having:a solid active medium (2) emitting at least in a wavelength range between 1.5 and 1.6 .mu.m, anda saturable absorber (4) of formula CaF.sub.2 :Co.sup.2+ or MgF.sub.2 :Co.sup.2+ or SrF.sub.2 :Co.sup.2+ or BaF.sub.2 :Co.sup.2+ or La.sub.0.9 Mg.sub.0.5-x Co.sub.x Al.sub.11.433 O.sub.19 or YAlO.sub.3 :Co.sup.2+ (or YAl.sub.5-2x Co.sub.x Si.sub.x O.sub.3) or Y.sub.3 Al.sub.5-x-y Ga.sub.x Sc.sub.y O.sub.12 :Co.sup.2+ (or .sub.-3 Al.sub.5-x-y2z Ga.sub.x Sc.sub.y Co.sub.z Si.sub.z O.sub.12) or Y.sub.3-x Lu.sub.x Al.sub.5 O.sub.12 Co.sup.2+ (or Y.sub.3-x Lu.sub.x Al.sub.5-2y Co.sub.y Si.sub.y O.sub.3) or Sr.sub.1-x Mg.sub.x La.sub.y Al.sub.12-y O.sub.12 :Co.sup.2+ (or Sr.sub.1-x Mg.sub.x-y Co.sub.y La.sub.z Al.sub.12-z O.sub.12, with o<y<x).

Abstract: A semiconductor Bragg reflector and to a method of fabricating it. The reflector comprises a plurality of stacked layers on a substrate of a III-V type material, one of the stacked layers forming a holographic grating. The layer forming the grating comprises an alternating succession of air pockets and of III-V type material. Such a reflector is particularly suitable for use in laser devices.

Abstract: An external cavity type wavelength-tunable light source including an optical amplifier on one end surface of which an antireflection film is coated, a diffraction grating arranged on an emission light axis of the optical amplifier on the side of the antireflection film and having wavelength selectivity, a reflector arranged on a reflection light axis of the diffraction grating, for reflecting a reflection light beam from the diffraction grating, and a wavelength tuning mechanism for tuning a wavelength of an lasing light beam by changing an angle of the reflector relative to the reflection light axis of the diffraction grating.

Abstract: A coated ceramic insulator in a laser chamber that is exposed to a gaseous environment where impurities in the ceramic insulator are prevented from detrimentally contaminating the laser chamber by a high-purity insulating coating. The insulating coating prevents chemical interactions between the ceramic insulator and the gaseous environment. In particular, the coating prevents contamination, by impurities in the ceramic insulator, of the lasing gas.

Abstract: The invention features an apparatus providing electromagnetic radiation including: a first non-linear optical crystal for converting input radiation from a laser into intermediate radiation; a second non-linear optical crystal for converting the intermediate radiation into output radiation; and a plurality of optics forming an optical cavity that encloses the first and second non-linear optical crystals, substantially confines and resonates the intermediate radiation, and has a cavity length matching the cavity length of the laser to within less than the coherence length of the input radiation. The apparatus can be used to convert the output from a multimode, diode-pumped, solid-state laser into high power ultraviolet radiation.

Abstract: Disclosed are both a housing and an assembly for a tunable external cavity laser. The housing includes: a base section, a motion section, and an actuator. The base section includes a proximal and distal portion, and the laser and the dispersive element mounted at respectively the proximal and distal portions such that energy emanating from the laser strikes the dispersive element leaving the dispersive element as a second beam at an angle with respect to the first beam which depends on wavelength. The motion section includes a proximal and a distal portion and a torsional member positioned at the proximal portion and the reflector positioned at the distal portion to reflect the second beam to the laser via the dispersive element, and the motion section supported by the base about the torsional member.

Abstract: An intracavity, frequency-doubled, external-cavity, optically-pumped semiconductor laser in accordance with the present invention includes a monolithic surface-emitting semiconductor layer structure including a Bragg mirror portion and a gain portion. An external mirror and the Bragg-mirror portion define a laser resonant-cavity including the gain-portion of the semiconductor layer structure. A birefringent filter is located in the resonant-cavity for selecting a frequency of the laser-radiation within a gain bandwidth characteristic of semiconductor structure. An optically-nonlinear crystal is located in the resonant-cavity between the birefringent filter and the external mirror and arranged to double the selected frequency of laser-radiation.

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

Abstract: A pulsed solid-state laser comprises an optical resonator and a solid-state laser medium placed inside the optical resonator. A saturable absorber, such as a semiconductor saturable absorber mirror device for passive mode locking is placed inside the optical resonator, and a pumping source is provided for exciting the laser gain medium to emit electromagnetic radiation. The pumping source emits pump radiation which impinges on the laser gain medium in the form of a non-diffraction-limited focused pumping beam. The product of the stimulated emission cross section times the spontaneous fluorescence lifetime is low for the laser medium, e.g., 0.1.multidot.10.sup.-23 cm.sup.2 s for Ti:sapphire; nevertheless, the laser yields a high output power of a few Watt even if pumped with a non-diffraction-limited pumping beam. Pumping with a non-diffraction-limited pumping beam makes feasible solid-state lasers with remarkably smaller sizes and lower costs, but with the same performance as known lasers.

Abstract: A laser transmitter based on a star coupler includes a separate controlled output port. An interferometric modulator is incorporated inside a laser cavity by means of a star coupler and enables modulation of the laser signal, independent of the means of wavelength selection used to determine the frequency of the laser.

Abstract: A laser light generating apparatus in which the laser light from a laser light source is intensified by an optical resonator arranged outside the laser light source and outputted after wavelength conversion by a non-linear optical crystal element arranged within the optical resonator. The laser light generating apparatus includes a laser light source for radiating the laser light, an optical resonator for resonating the laser light radiated from the laser light source, a non-linear optical crystal element having an anti-reflection film formed on its laser light incident surface and an aperture for interrupting the light reflected by the non-linear optical crystal element within the optical resonator. The non-linear optical crystal element is arranged in the optical resonator so that a line drawn normal to the laser light incident surface will be obliquely inclined relative to the optical axis of the laser optical resonated within the optical resonator.

Abstract: An external resonator type variable-wavelength LD light source which can compensate errors of a change in an oscillation wavelength caused by a change in an LD driving current, a change in the oscillation wavelength caused by a change in a temperature of an entire light source unit, a difference between set and actual wavelengths caused by mechanical factors to thereby ensure a wavelength reproducibility of 0.001 nm even when the LD driving current or operational temperature varies.

Abstract: A grating based line-narrowing apparatus having a prism beam expander with at least four prisms. Each prism is positioned at an incidence angle between 67 and 71 degrees. A single layer coating of high refractive index, robust material, such as Al.sub.2 O.sub.3, is applied to the hypotenuse face of each prism, providing an efficient, anti-reflection coating. In a preferred embodiment the incident angle of the four prisms are each at about 68.2 degrees. The laser of the preferred embodiment has similar line narrowing efficiency and bandwidth as that for a laser with a 3 prism, ideal multi-layer anti-reflection coated beam expander. The primary benefit of the new four prism arrangement is that the prism coatings should be much less expensive and have greatly increased durability. Applicants have tested the new prisms for 30 million, 10 mJ pulses in air with no noticeable degradation. No present day dielectric multi-layer stack coating could survive such exposure.

Abstract: The present invention provides a highly compact vertical cavity surface emitting laser structure formed by a lateral oxidation process. Specifically, the present invention allows for the use of well-controlled oxidized regions to bound and to define the aperture of a laser structure in a current controlling oxidation layer, wherein the aperture comprises a conductive region in the oxidation layer. These oxidized regions are formed by the use of a pre-defined bounding pattern of cavities etched in the laser structure, which allow the embedded oxidation layer to be oxidized, and which results in a highly reproducible and manufacturable process.

Abstract: A wavelength tunable semiconductor laser light source, which has an external resonator semiconductor laser source unit; an optical filter for selecting an output beam of the external resonator semiconductor laser source unit in a single mode; a drive unit for changing wavelength of a transmitted beam or of a reflected beam, from the optical filter; and a control unit for controlling the drive unit; a first beam splitting device for receiving the output beam of the external resonator semiconductor laser source unit as one of incident beams and for outputting it into two branches; an etalon for receiving one of output beams from the first beam splitting device; a measuring unit for etalon transmittance, for measuring a transmittance of the etalon to transmit it to the control unit; and a wavemeter for specifying a wavelength of the output beam of the semiconductor laser source unit with an accuracy in a free spectral range of the etalon, on the basis of the output beam of the semiconductor laser source unit or

Abstract: A Q-switched laser system, in particular for laser lithotripsy, has a laser-active medium (2.1) in a resonator, an optical pumping arrangement (2.3) and a passive Q-switch (3.2). A resonator extension (1.2) having an optical waveguide is associated to the laser-active medium (2.1) in order to increase the laser pulse length.

Abstract: Disclosed is a mirror mounting device and method for beam path alignment of an optical cavity for a ring laser gyroscope. The ring laser gyroscope is of the type that includes a block having an optical cavity that defines a closed loop optical path. A light source directs a light beam into the path. The block includes mounting surfaces for mirrors that reflect the light beam at the optical path corners. The mirror mounting device is associated with one of the block mounting surfaces and acts to orient a concave reflective surface of one of the mirrors such that the light beam is aligned within the closed loop optical path and is at its maximum intensity irrespective of the position of the concave reflective surface of the mirror relative to its mounting surface.

Abstract: A semiconductor light emission device includes a semiconductor light amplifier, a mirror which reflects light emanating from an end face of the semiconductor light amplifier to return to the end face of the semiconductor light amplifier and a wavelength selector which is inserted into the optical path of the light. The wavelength selector is a Lyot filter, an etalon or a combination of a Lyot filter and an etalon.

Abstract: An intracavity doubled single longitudinal mode laser is disclosed which provides stable (i.e., low amplitude variation in its output beam intensity), efficient operation. An associated method is also disclosed. The laser includes an input mirror and an output mirror defining a resonant cavity and a light path within the resonant cavity and between the mirrors. The output mirror is configured to be substantially transparent to an output wavelength produced within the cavity. A lasant material is positioned in the light path for producing light at a desired fundamental wavelength and possibly other, unwanted wavelengths. Polarizing element and a type I doubling material are also positioned in the light path. During operation of the laser, the polarizing element polarizes the desired fundamental wavelength as well as the unwanted wavelengths of light produced by the lasant material. The type I doubling material then produces output wavelengths at twice the frequency of any wavelengths passing therethrough.

Abstract: A laser system having a resonant cavity that is stable in one axis so that a wavelength selector can be used for producing a narrow line output, and is unstable in an orthogonal axis for high energy extraction efficiency and for low output beam divergence. The resonant cavity terminates at one end with a cylindrical mirror and at the other end with a dispersive wavelength selector. A gain medium is disposed in the resonant cavity, and is excited by a power supply to generate a laser beam that oscillates in the resonant cavity. A portion of the laser beam is coupled out of the resonant cavity as an output laser beam. The cylindrical mirror has a cylindrical reflecting surface oriented to diverge the laser beam at a first azimuthal angle relative to an axis of the resonant cavity. The dispersive wavelength selector disperses the laser beam as a function of wavelength at a second azimuthal angle relative to the resonant cavity axis. The second azimuthal angle is orthogonal to the first azimuthal angle.

Abstract: A highly stable variable wavelength laser light source of simple construction and having excellent productivity is provided. With the variable wavelength laser light source wherein a laser diode is provided with a non-reflection film on the front end face, and a high reflection film on the rear end face, outgoing light from the laser diode is condensed by a lens, branched out by a recombination and branching filter after falling thereon, and sent out to a wavelength selector selecting a light beam of a specific wavelength, which is returned to the laser diode via a recombination and branching filters and the recombination and branching filter and after condensed by the lens so that a laser beam is produced through resonance by the external resonator composed of an optical return path section and the high reflection film, and the laser beam is delivered from an output port via a recombination and branching filter.

Abstract: An etalon is disposed in a resonator of a laser to make the laser oscillate in a single longitudinal mode. Opposite end faces of the etalon through which light travels are provided with coating by ion-assisted deposition to prevent output fluctuations of the laser due to changes in environmental moisture and/or aging of the laser. Preferably the coating is of HfO.sub.2 and SiO.sub.2. In accordance with a second aspect of the present invention, there is provided a single longitudinal mode laser comprising a resonator and an etalon which is disposed in the resonator to make the laser oscillate in a single longitudinal mode, wherein the improvement comprises that opposite end faces of the etalon through which light travels are provided with coating by ion-assisted deposition. Further, the resonator may be contained in an airtight casing.

Abstract: An object of the present invention is to provide a wavelength selectable laser oscillator in wavelength tunable laser by which high-speed tuning of wavelength can be achieved while utilizing continuous-wave laser beam as the excited laser beam.

Abstract: Superresolution elements which provide masks and are integrated into superresolution lenses, and in confocal imaging, optical disk and reprographic systems and laser pattern generation systems. The elements are phase-only elements, where the phase transmittance varies across the diameter of the element while the amplitude transmission is kept to one, although the amplitude can be varied to provide more design flexibility. These element filters can be fabricated by means of a variety of techniques including diffractive optics technology, holographic methods, thin film deposition, and as gradient-index elements.

Abstract: A single-mode fiber-coupled multi-wavelength laser, wherein, for suppressing higher order transverse modes of the laser cavity than TEM.sub.oo of at least one laser emission wavelength or for increasing the beam waist diameters of the transverse laser cavity modes or for increasing the signal-to-noise level of the output of the laser at least at one emission wavelength, one or more of the following is selected:a) at least one resonator mirror movable along the resonator axis in order to vary the resonator length;b) at least one resonator mirror tiltable until a surface normal thereof encloses an angle (0.noteq.0) with the resonator axis;c) at least one resonator mirror being replaced by another concave mirror with different curvature radius;d) at least one resonator mirror being replaced by a flat mirror; ande) at least one mirror holder allowing the interchangeable use of several mirrors with different curvature radii.

Abstract: Apparatus and method are disclosed for minimizing performance degradation in a laser device having a laser cavity operating in a predetermined spatial mode having predetermined light beam wavefronts within the laser cavity mode. An optically transmissive unit is placed within the laser cavity and has at least one intracavity optical surface that may be positioned at or provides one end of a laser medium that is within the laser cavity with the intracavity optical surface being coincident with the laser mode wavefronts in order to minimize power losses in the laser device due to contamination buildup at the intracavity optical surface. The optic unit may also include a second optical surface that is less exposed to contamination and has a configuration suitable for providing needed focal properties for the optic unit, and one or more of the optical surfaces may have a reflection coating thereon.

Abstract: The invention relates to a microlaser cavity switched with the aid of an electrooptical material (54). Electrodes (84, 86) are produced on support elements (80, 82) and the latter are then applied on either side of the electrooptical element. Solid electrodes can also be applied on either side of the electrooptical material.

Abstract: A Q-switch laser apparatus includes a laser cavity formed with a pair of reflective surfaces having a laser medium mounted therebetween and a power supply operatively connected to the laser cavity to pump the laser medium. An electro-optic Q-switch is mounted in the laser cavity in a saturable absorber of less than 100% saturable transmittance is located in the laser cavity between the laser medium and the electro-optic Q-switch for suppressing prelasing in the laser. The saturable absorber may be a Cr4+:YAG used with an electro-optic Q-switch of LiNbO.sub.3. The method includes selecting the laser apparatus and selecting a saturable absorber of less than 100% saturable transmittance and attaching the selected saturable absorber in the laser cavity between the laser medium and the electro-optic Q-switch for suppressing prelasing therein.

Abstract: The invention relates to a remote gas detection process comprising: the emission of a first radiation (4), at at least one absorption wavelength for the gas to be detected, with the aid of a first switched microlaser, in the direction of a test area (6), the production of a first signal (S), representative of the radiation quantity scattered by said gas in response to the interaction between the molecules or atoms of said gas and said first radiation. The invention also relates to an apparatus for performing this process.

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: A solid-state laser apparatus is composed of a semiconductor laser device 17, a laser medium 13 for generating oscillated light, a non-linear optical device 12 for converting the oscillated light to non-linear light, a laser holder 17a and a base plate 19 for holding the semiconductor laser device 17, and a crystal holder 3 for holding the laser medium 13 and the non-linear optical device 12. The laser holder 17a, base plate 19 and crystal holder 3 are fixed with an adhesive or the like after positional adjustment under light pressure and temporary tightening. A laser diode pumped solid-state laser apparatus is thus obtained which is simplified in assembling and positioning of optical components and can be stably operated regardless of temperature changes.

Abstract: A laser system capable of high speed silicon wafer dicing is disclosed. A laser with high average power, high repetition rate, ultra-short pulsewidth, and excellent beam quality is described. This is achieved by the use of high power diodes used to uniformly pump an improved Nd:YAlO.sub.3 crystal, resulting in a beam with excellent quality. In addition, a beta-barium borate (BBO) crystal, used in conjunction with drift step recovery diodes (DSRDs), forms a high speed optical switch which can be used to cavity dump the laser.

Abstract: A semi-monolithic ring cavity for a second harmonic generation of laser frequency including a nonlinear crystal, an input mirror, an output mirror, a first point, at which a fundamental wave is incident onto the input mirror, a second point, at which the fundamental wave is incident onto the output mirror along with a second harmonic wave, and a third point, at which the fundamental wave reflects totally from a side surface of the nonlinear crystal. One of the input and output mirrors is coated with a dielectric and separated from the nonlinear crystal whereas the other mirror is formed on the nonlinear crystal. The fundamental wave forms a ring cavity in such a manner that the second harmonic wave is generated only along an axis extending through the first and second points. The semi-monolithic ring cavity exhibits a stable frequency characteristic and a high transform efficiency when a second-harmonic generation of continuous-wave laser frequency is carried out.