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: An integrated multi-wavelength transmitter, particularly useful in a wavelength-division multiplexed optical communications system. An arrayed waveguide grating has feedback channels between two coupling regions and is constructed such that, at each coupling region, one port carries all the optical signals of differing wavelengths while a set of other ports carry wavelength-separated signals. The multi-wavelength signal from a first coupling region is reflected from a mirrored surface back into the first coupling region and the arrayed waveguide grating, the mirrored surface thus forming one end of an optical cavity. Similar elements are arranged between corresponding single-wavelength ports of the two regions. The channel from the second coupling region is split into two parts. One part is passed through an optical gain region and is reflected back from the mirrored surface through the power splitter, now acting as a combiner.

Abstract: A laser includes a split-wave hybrid resonator that produces a high quality laser beam from a low gain laser medium. The split-wave hybrid resonator includes a resonator cavity formed by a pair of resonator mirror surfaces positioned at opposite ends of the laser medium and a pair of resonator walls positioned on opposite sides of the resonator cavity. The resonator walls are separated from each other by a separation distance such that the resonator cavity has a Fresnel number between approximately 0.5 and 1.5. At least one of the resonator walls includes a first ring oscillation filter adjacent to the lasing medium to filter out ring oscillations within the laser medium. One or more of the resonator walls may include first and second wall portions angled with respect to each other to form a wave-front splitting interferometer. The resonator mirrors are tilted off-axis with respect to the resonator walls.

Abstract: Method for preparing a laser cavity resonator for use in a Raman gas analyzer, that resonator comprises a V-shaped housing which comprises a first and a second channel for the laser beam in a V-arrangement. The method allows the adjustment of the resonator in the manufacturing site and provides a high mechanical stability and reliability of the system and accelerates the manufacturing of the resonator. The resonator received by the method comprises adjusted mirrors fixed to the housing so that the resonator can be transported and installed in the analysis system at its place of application.

Abstract: A diffusion-cooled laser has a lasing region shaped to provide a high power output laser beam of a high optical quality. The lasing region, which contains a lasing medium, has a narrow-aperture section and a free-space section. The narrow-aperture section is defined by resonator walls spaced apart a sufficiently small distance that enables effective excitation and cooling of the lasing medium. The free-space section is defined by resonator walls spaced apart a sufficiently larger distance that enables the laser beam to expand without restriction from the resonator walls in the free-space section. The narrow-aperture section enables the laser to generate a high power laser beam using a relatively low (40 MHz) ISM frequency. The free-space section allows the laser beam to expand sufficiently to exit the lasing region with a shape that is easily focused by inexpensive optical elements.

Abstract: A microwave excited gas laser apparatus includes a single unit having at least first, second, third, and fourth waveguides. The first and second waveguides meet at a first intersection. The third and fourth waveguides meet at a second intersection. A discharge tube contains a laser medium gas, and extends through the first and second intersections. Microwaves are radiated into the first, second, third, and fourth waveguides. The discharge tube in the first intersection is exposed to a microwave propagated along the first waveguide and a microwave propagated along the second waveguide. The discharge tube in the second intersection is exposed to a microwave propagated along the third waveguide and a microwave propagated along the fourth waveguide.

Abstract: A high-Q pump cavity is formed from undoped crystal pieces that are diffusion bonded to a doped core of the same crystal host material. The resulting monolithic pump cavity has 2 opposing convex-curved sides which have a highly-reflective coating on their outer surfaces, except in narrow slit-shaped areas on each curved side through which laser-diode-supplied pump light enters the cavity. The curvature of the two curved sides is such that nearly all the pump light rays that pass through the slit-shaped areas are focussed by the curvature onto the doped core, and rays that enter the cavity are redirected through the doped core many times, resulting in efficient, uniform absorption. The cavity has two opposing flat sides that interface with metal heat sink blocks to facilitate the removal of internally-generated heat. Thermally induced astigmatic lensing caused by this heat is countered by cavity design in which the core shape and the dimensions of the cavity minimize this astigmatism.

Abstract: A transverse RF pumped gas laser has a large area discharge which is of generally rectangular shape in all plan views. In cross-section the geometry of the discharge has a longer and a shorter dimension, the longer dimension being between the electrodes to which RF power is supplied and the shorter dimension, suitable for guiding intracavity laser light, being defined by ceramic side walls.

Abstract: A superfluorescent fiber source outputs highly polarized light without a substantial decrease in output power efficiency. According to one embodiment, a polarizer is spliced within the superfluorescent fiber at a selected location along the length of the fiber (e.g., near the middle of the fiber). According to another embodiment, the entire length of the superfluorescent fiber is polarizing to thereby assure that one of the polarizations of light is substantially extinguished while the other polarization of light is nearly double the power which that polarization would have if the polarizer were not present within the superfluorescent fiber. In this manner, superfluorescent sources can be adapted especially for use in fiber optic gyroscopes, or the like, which require highly polarized light, without a substantial reduction in efficiency.

Abstract: A waveguide laser (10) incorporates a guide (12) and two concave resonator mirrors (14, 16). The guide (12) is of square section with side (2a), and of length L equal to 4a.sup.2 /.lambda., where .lambda. is a laser operating wavelength. The mirrors (14, 16) are phase matched to respective Gaussian intensity profile radiation beams with beam waists at respective waveguide end apertures (20, 22). Each beam waist has a radius w.sub.0 in the range 0.1a to 0.65a to avoid waveguide edge effects and excitation of unwanted high order waveguide modes. The laser (10) has good transverse spatial mode characteristics.

Abstract: A frequency converting laser device is disclosed which includes a laser diode adapted to produced an output laser beam and an optical fiber coupled to the output of the laser diode and including a built-in grating in the optical fiber arranged so as to provide a beam having a specific wavelength and to reflect a small portion of such beam back into the laser diode while transmitting the beam so that the laser diode will produce a beam of that wavelength. The device further includes a frequency converting structure adapted to receive the transmitted beam of light and to change the frequency of the input beam to produce the output beam at the specific frequency.

Abstract: A laser device incorporates a rectangular multi-mode beamsplitter waveguide connected at one end to a retro-reflecting mirror. The beamsplitter waveguide is connected at a second end to an output coupling waveguide and a reflection coupling waveguide. The reflection coupling waveguide is terminated by a second retro-reflecting mirror. Radiation produced within the device is reflected by the mirror and coupled to the two coupling waveguides in a manner such that a partially reflecting mirror is not required at an output to the device.

Abstract: Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies.

Abstract: A harmonic generator laser system which features a distributed Bragg reflector (DBR) or distributed feedback (DFB) tunable diode laser coupled to a quasi-phasematched (QPM) waveguide of optically nonlinear material. Tuning of the DBR laser may be achieved either thermally or via current injection, or both, halving the wavelength of a red laser into the visible blue spectral band. Thermal tuning may provide a coarse tuning adjustment, while injected current may provide fine tuning accessible to a user. Separately or in combination with current tuning, a modulation signal may be applied to the DBR laser for achieving an intensity modulated or a pulsed output. In another embodiment, modulation may be achieved by frequency modulation of the laser. A very compact tunable blue laser is formed. In yet another embodiment a double clad fiber amplifier is disposed between the tunable laser and the waveguide.

Abstract: A waveguide laser comprises a laser-active medium, a pump source for the laser-active medium and a resonator with a waveguide extending in an axial direction and formed from a cylindrical, outer optical waveguide surface and a cylindrical, inner optical waveguide surface. A resonator radiation field extends substantially parallel to the axial direction between the outer and inner optical waveguide surfaces. The waveguide laser further comprises two cavity mirrors between which the resonator radiation field extends and of which at least a first mirror comprises successive maximum and minimum reflectivity values in a direction azimuthal to the axial direction. The maximum and minimum reflectivity values of the first cavity mirror, viewed in the azimuthal direction, are arranged at the location of maximum and minimum intensities of a selected azimuthally closed mode of the resonator, which mode is enclosed by the resonator radiation field.

Abstract: A semiconductor laser emits semiconductor laser light with TM-mode oscillation. The emitted semiconductor laser light is collimated by a first collimating lens, passes through a Brewster plate that is arranged so that the direction of Brewster plane's p-polarized light is in alignment with the direction of polarization of the emitted semiconductor laser light, and is coupled to an incident portion of a wavelength-conversion waveguide by means of a focusing lens. While being guided through the waveguide, the emitted semiconductor laser light is converted into second-harmonic light by means of a polarization inversion region. Semiconductor laser light emanating from an emitting portion of the waveguide reflects from an output mirror towards a diffraction grating, for modulation in wavelength. Second-harmonic light emanating from the emitting portion of the waveguide is outputted from the output mirror.

Abstract: A waveguide carbon dioxide (CO.sub.2) laser includes a six-sided laser block comprising first and second triangular end sections and a rectangular insert block. The two triangular end sections include a waveguide grid comprising two sets of parallel waveguide channels intersecting at right angles and optically coupled by strip mirrors disposed along the edges of the triangular sections. The rectangular insert block also includes a set of parallel waveguide channels which are congruent with and aligned parallel to the waveguide channels of the two triangular end sections, thereby extending the cavity length of a multiply folded waveguide laser without a corresponding increase in the number of optical folds, the number of folding mirrors, or the value of distributed loss.

Abstract: A microwave powered gas laser apparatus contains a gas medium, and a device for exciting the gas medium to a high energy state by a plurality of microwaves. Directions of vibrations of electric fields of the microwaves are different from each other. There may be provided a device for making the microwaves into standing waves respectively, and a device for exposing the gas medium to antinodes of electric fields of the standing waves.

Abstract: A dual wavelength pumped low noise fiber laser includes a fiber laser 10 comprising a pair of Bragg gratings 14,16 at opposite ends of a fiber laser cavity 18 which is co-doped with two rare-earth dopants, Er.sup.+3 Yb.sup.+3, so as to allow lasing to occur at a lasing wavelength .lambda..sub.L. A first pump signal 20 efficiently pumps the Yb to the excited state and the Yb energy is transitioned to the Er atoms which ultimately lase at the desire lasing frequency. Because Yb is pumped so efficiently, high pump absorption is achieved, thereby providing high laser output power and, consequently, reduced RIN. Simultaneously, a second pump signal 52 directly pumps the Er at a different wavelength .lambda..sub.P2 which populates the lasing transition more quickly, thereby allowing sufficient bandwidth of a closed loop control on the second pump signal 52 to control low frequency RIN spiking due to relaxation oscillations in the laser.

Abstract: A light source including a gaseous medium which is excited to a light-emitting state by means of a microwave electromagnetic field, wherein the electromagnetic field is generated by circularly polarised microwave radiation. A preferred form of the invention is a laser.

Abstract: A composite, glass or crystalline laser rod having a doped, light-absorbing core portion surrounded by a transparent cladding portion that is either undoped or doped with a nonabsorbing material is side-pumped with a plurality of laser diodes dispersed angularly around the laser rod. A reflective coating or sleeve substantially surrounds the laser rod, except for entrance slits for the pump light, to confine unabsorbed pump light in the crystalline laser rod by reflecting and re-reflecting the pump light in the rod to increase the likelihood of absorption by the core portion. The reflective coating is substantially reflective of all the pump light, but it can be transparent to laser radiation emission by the rod. An absorptive coating that absorbs radiation of the wavelength of the laser radiation emission of the rod can be positioned around the outside of the reflective coating to absorb lateral laser emission of the rod.

Abstract: A high-power unstable resonator semiconductor laser (14) emits optical output of greater than 50 mW in a wavelength range of 700-1100 nm. A grating (116,136) may be positioned external to URSL (14) to control the spectral bandwidth and wavelength output of the waveguide pumping beam (74). Alternatively, URSL (14) may be fabricated with a distributed feedback (DFB) grating or a distributed Bragg reflector (DBR). Infrared waveguide pumping beam (74) generated by such a high-power unstable resonator semiconductor laser (14) is coupled into a nonlinear waveguide (28) and converted to visible or near ultraviolet output (100) through the process of second-harmonic generation.

Abstract: A gas laser 1 such as a .sup.13 CO.sub.2 -laser emits at two different wavelengths (.lambda..sub.1, .lambda..sub.2) with a sine-shaped adjustment of a resonator mirror or a grating 13 such as a Littrow grating. The gas laser emits radiation at the two desired wavelengths (.lambda..sub.1, .lambda..sub.2) in two mutually adjacent intervals of the resonator length L because of a suitable dimensioning of the grating 13 with respect to grating structure and angle position, the outcoupling factor of the outcoupling mirror 12, the resonator length L and the composition of the gas of the laser. The laser emission is inhibited at the crossover between the two intervals and the sine-shaped modulation (for example with a piezo element) of the resonator length L is essentially symmetrical about this crossover. The invention is also directed to an arrangement for detecting a substance such as NH.sub.3 in a flue gas.

Abstract: A single mode laser with a laser cavity consisting of an active medium and a first and second reflectors with an antiguide region or layer having a high refractive index positioned adjacent to the laser cavity to bleed off higher order lasing modes and preventing them from attaining the lasing condition. Specifically, light belonging to higher order modes leaks or bleeds into the antiguide region from the laser medium and from the first and second reflectors. When spacers for selecting the desired wavelength of laser light are provided, the light travelling through them leaks into the antiguide layer as well.Optimization of the bleeding of higher order modes into the passive antiguide region can be achieved by adjusting a taper angle of the laser cavity. Furthermore, by adjusting the ratio of the equivalent refractive index of the laser cavity and the passive antiguide region single mode operation at high current levels can be realized for apertures as large as 30 .mu.m.

Abstract: A laser cavity configuration employs a mode reshaping structure in a solid state waveguide. The mode reshaping may be by means of an adiabatic taper. Polarization switching may be employed in connection with the mode reshaping to obtain a high output power in a single transverse spatial mode from an integrated external cavity multiple-mode diode laser device. The structure provides stabilization and rapid tuning of the frequency of the diode laser, as well as use substantially all of the available power of the diode laser operating multimode. Various configurations and combinations are described. An advantage is that an integrated structure can provide output of the laser in a waveguide with single mode for subsequent applications. The external cavity diode laser according to the invention is consistent with a planar manufacturing process such that high volume, low cost products can be achieved.

Abstract: A polarized fiber laser source includes a fiber laser 10 comprising a pair of Bragg gratings 14,16 at opposite ends of a fiber laser cavity 18 which is doped with a rare-earth dopant so as to allow lasing to occur at a lasing wavelength .lambda..sub.L. A grating tap 26 is provided along a portion of the laser cavity 18 to couple-out a predetermined amount of light along one polarization, e.g., the "s" polarization", at the lasing wavelength .lambda..sub.L. This causes one polarization mode to experience more loss than the other, thereby allowing the fiber laser to lase only on the less lossy polarization mode and causing the laser output light 40 to be polarized only along such polarization.

Abstract: A laser cavity configuration employs polarization switching to obtain a high output power in a single transverse spatial mode from an integrated external cavity diode laser device. The structure provides stabilization and rapid tuning of the frequency of the diode laser. An advantage is that an integrated structure provides output of the laser in a waveguide with the correct polarization for subsequent applications while supporting optimal polarization in a solid state active medium. The external cavity diode laser according to the invention is consistent with a planar manufacturing process such that high volume, low cost products can be achieved.

Abstract: According to the present invention there is provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein discharge is obliquely generated within the rectangular section of a discharge space. There is also provided a laser apparatus with a pair of preliminary discharge excitation electrodes which can readily initiate discharge. There is further provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein provided is a pair of discharge excitation electrodes located in the major side direction of discharge space whose length is more than three times as long as that of minor side direction thereof. There is further provided a laser apparatus with a pair of discharge excitation electrodes whose dimension is smaller than that of a pair of dielectric plates, which apparatus can prevent undesirable discharge.

Abstract: A nonlinear optical device, operating in an optical bistability mode, capable of carrying out amplification, commutation, switching and computing of optical signals, comprises, a pair of directional couplers formed by optically coupling a pair of waveguides and a pair of nonlinear circular resonators and an optical transistor incorporating an optical mixer of bifurcation optical active type capable of functioning also as a phase modulator.

Abstract: A ring laser is described, which has a ring (1) in which laser radiation is generated. A coupler (4) couples a part of the radiation in the form of two waves (7,8) to two waveguides (5,6). A combiner (11) combines the two waves to an output wave (12) in an output waveguide (13). By providing a reflector (16) in the output waveguide, a part of the output wave is reflected to the ring via the combiner, the two waveguides and the coupler. The radiation waves travelling in the ring couple to the reflected wave and thereby acquire a well-defined phase difference. The resultant phase equality of the two waves (7,8) at the input of the combiner ensures that the powers of the waves are added in phase so that the ring laser supplies the maximum possible power.

Abstract: A laser beam generator has a pair of opposing mirrors. A reflecting surface of at least one of the opposing mirrors is constituted by a conical surface having a vertex angle of 90 degrees in order to tangentially polarize a laser beam. This conical surface is diverged toward the other opposing mirror at an angle of 45 degrees with respect to an optical axis from its vertex held alignment with the optical axis.

Abstract: A diffusion-cooled CO.sub.2 stripline laser having reduced ignition voltage is provided. In order to facilitate the ignition of the stripline laser, an auxiliary discharge path is provided which is formed either by segmentation of the HF electrode or by at least one auxiliary electrode that is arranged along the electrode surface and adjacent to the discharge path.

Abstract: In a stripline laser, each electrode is fashioned as a composite of a carrier part having a mechanically stable profile and a plate-shaped electrode part having integrated cooling that is hard-soldered or welded thereto and faces toward the discharge gap.

Abstract: A laser capable of generating polychromatic or white light radiation is realized by employing dispersive and reflecting elements as the ends of a simple laser resonator cavity. The dispersive element either solely or in combination with an intracavity lens is arranged such that each wavelength component of the white light radiation is amplified by a different portion of the active medium. More specifically, forced oscillation or positive feedback for each wavelength component is achieved by operating a diffraction grating in an auto-collimation configuration or through the use of a distributed bragg reflector having a spatially varying index of refraction.

Abstract: A frequency tunable waveguide extended cavity laser formed with a laser diode, a channel waveguide comprising an electro-optic material, a frequency tunable Bragg grating reflector formed in or on the channel waveguide and a pair of conducting electrodes. The frequency of radiation produced by the frequency tunable waveguide extended cavity laser is adjusted so as to be at a desired frequency by applying a voltage to the conducting electrodes. The device further incorporates a waveguide nonlinear optical frequency converter to produce frequency convened radiation at a higher frequency. Feedback means are included for dynamically controlling the desired frequency so as to be at a frequency for optimum frequency conversion.

Abstract: An improved slab-waveguide CO.sub.2 laser which includes two parallel, rectangular, flat, spaced-apart, slab electrodes whose surfaces excite a laser gas and guide laser light in a plane perpendicular to the surfaces of the slab electrodes. The component of the light propagating parallel to the electrode surfaces is not guided and is acted on only by resonator mirrors which form an unstable resonator. The improved slab-waveguide CO.sub.2 laser operates on a single vibrational transition of the CO.sub.2 molecule by employing wavelength selective optics.

Abstract: A gas laser, in particular a CO.sub.2 laser, contains as laser medium a gas that is excited into a plasma by a HF energy supply, in particular a microwave energy supply, whereas the HF waves are coupled into the laser medium (4) through a rectangular waveguide (1). In order to obtain a compact structure with an efficient coupling of the HF energy, coupling is ensured by means of a ribbon-shaped waveguide (3) that projects into the rectangular waveguide (1) and thus also allows the outcoupling on all sides of the rectangular waveguide.

Abstract: A tunable laser formed on a semiconductive wafer comprising a plurality of monolithically integrated optical amplifiers and a planar optical multiplexer is disclosed. According to the invention, one of the optical amplifiers is activated by energy, which amplifier produces a signal. The signal is carried along a waveguide associated with the optical amplifier and enters a reflective Dragone router, which is the preferred optical multiplexer. The reflective Dragone router functions, in conjunction with the activated optical amplifier, to define a wavelength selective optically transmissive pathway to create lasing action. Facet mirrors are cleaved in the semiconductive wafer defining the lasing cavity which includes the optical amplifiers, associated waveguides and the reflective Dragone router.

Abstract: Optical guiding of intense laser pulses over a distance of more than one Rayleigh length in a plasma is discussed herein using a multi-pulse technique. The first pulse or pulse sequence prepares a shock-driven, axially-extended radial electron density profile which guides a second pulse or sequence of pulses. The profile is also capable of guiding x-rays. The channel will support mode structure exactly analogous to that of an optical fiber waveguide. The method provides a means for guiding of a high intensity optical laser pulse or x-rays over distances well in excess of a Rayleigh length. The distances over which guiding occurs is limited only by the length of the preformed plasma and absorption and possible backscattering of the guided EM radiation. Applications of the method allow for compact x-ray laser devices and electron particle accelerators.

Abstract: A self-frequency-doubler laser element having a three-dimensional optical waveguide includes a first transparent insulating substrate having both a DFB grating and a grating reflector formed on one side of the DFB grating, a Nd.sup.3+ -ion-doped thin glass film laid over the first transparent insulating substrate, a thin nonlinear optical film laid over the thin glass film, a second transparent insulating substrate laid over the thin nonlinear optical film, and a thin reflecting film laid over the second transparent insulating substrate, wherein the following conditions are satisfied: nf-ng=0.01 to 0.05, and nf and ng are greater than ns and nc, where ns, ng, nf, and nc are the refractive indices of the first transparent insulating substrate, the thin glass film, the thin nonlinear optical film, and the second transparent insulating substrate, respectively.

Abstract: A slab laser amplifier array includes a plurality of parallel, stacked, laser resonators, with each resonator having a walk-off mode of propagation of laser light from an input side of the resonator to an output side of the resonator where the exiting light diffracts around the resonator mirror. A source of a plurality of phase related, for example co-phasal, light beams supplies phase related light to each input side. The source of phase related light may be a source of one single mode beam followed by a telescope with an aperture having plural stops or a co-phasal array of laser resonators. A laser array of open resonators also has circular concentric electrodes.

Abstract: Method and arrangement for locking a laser to an external cavity that is electronically tunable to provide an optical source that is highly coherent and which is frequency stabilized over a variable frequency range. Preferably, an injection laser is tightly coupled to an external acousto-optic cavity having a reflective mirror on its back facet and carried on an electro-optic crystal substrate. A transducer is coupled to the external cavity and converts an electrical sinusoidal input signal into an acoustic wave which travels along the electro-optic crystal substrate to modulate the refractive index of the material along the optical waveguide. The periodicity of the refractive index along the waveguide is accordingly determined to be equal to one half wavelength of the acoustic frequency propagating in the waveguide which locks the laser at a particular optical frequency determined by the refractive index profile. The arrangement is particularly desirable for frequency division multiplexing applications.

Abstract: An all metal, microwave-pumped, waveguide CO.sub.2 laser includes a waveguide providing a vacuum envelope containing the CO.sub.2 gas having a longitudinal ridge extending at least partially across the width of the waveguide and extending along a length of the waveguide and a ceiling facing the ridge. The ridge and ceiling have horizontal surfaces facing one another which together function as an optical waveguide of the laser and define a longitudinal optically active region therebetween which, in the preferred embodiment, opens out into remaining portions of the waveguide along either side of said ridge. A pair of reflecting mirrors are located at each end of said optically active region and an antenna or ramped waveguide couples a microwave source into the waveguide.

Abstract: According to the present invention there is provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein discharge is obliquely generated within the rectangular section of a discharge space. There is also provided a laser apparatus with a pair of preliminary discharge excitation electrodes which can readily initiate discharge. There is further provided a laser apparatus capable of efficient oscillation with an excitation power source with comparatively low frequency, wherein provided is a pair of discharge excitation electrodes located in the major side direction of discharge space whose length is more than three times as long as that of minor side direction thereof. There is further provided a laser apparatus with a pair of discharge excitation electrodes whose dimension is smaller than that of a pair of dielectric plates, which apparatus can prevent undesirable discharge.

Abstract: In order to improve a wave guide laser comprising a wave guide arranged between two resonator mirrors and having an outer cylindrical wave guide surface and an inner cylindrical wave guide surface facing the outer surface and arranged within this outer surface in spaced relation thereto, the two surfaces together forming a wave guide having a radiation coherent in the entire wave guide and essentially expanding in axial direction, and a high-frequency excited and diffusion-cooled laser gas arranged between the wave guide surfaces, such that the high-power Laser beam can be outcoupled by an element which is constructionally simple to produce and inexpensive, it is suggested that the second resonator mirror be composed in azimuthal direction of a plurality of successive reflecting segments, that outcoupling openings for the laser radiation to be outcoupled be provided between the respective reflecting segments and that the entire radiation expanding in the wave guide be diffraction-coupled in azimuthal directio

Abstract: Mixing power laser apparatus, comprising a generator of a flow of excited nitrogen (1), and structure (6; 19) to introduce a flow of CO.sub.2 into the flow of excited nitrogen. The generator (1) is of the cold corona electric discharge type operating at a pressure greater than 0.3.times.10.sup.5 Pa, and is coupled to a waveguide (2) with mirrors (3, 4) opposed along a principal direction of the waveguide. For use particularly in cutting material.

Abstract: A diffraction limited working beam at a given frequency is amplified without degrading its diffraction limited quality by diverting a minor portion of the beam as a probe beam, and amplifying the remaining portion of the working beam with a high power pump beam at a different wavelength. The amplification takes place in a host medium that has a rare earth dopant with an energy transition from the pump beam's wavelength to the wavelength of the working beam. The resulting amplified working beam is non-diffraction limited. The probe beam is frequency modulated and coupled with the amplified working beam in a second host medium that also has a rare earth dopant. Energy is transferred from the amplified working beam to the modulated probe beam through a resonant energy transfer in the second host medium, producing an amplified output beam at the working beam frequency that retains the diffraction limited quality of the probe beam.

Abstract: A laser includes a soliton supporting waveguide of SiO.sub.2 --Al.sub.2 O.sub.3 --P.sub.2 O.sub.5 with an erbium doping level of 1100 ppm, the fibre having a core radius of 2.5 .mu.m and a core-cladding refractive index difference of 0.015 operated such that the solitons propagating in the waveguide have a soliton period greater than the amplification period of the laser.

Abstract: A resonator design is disclosed particularly suited for a RF excited, carbon dioxide, slab waveguide laser. The laser includes a pair of elongated electrodes spaced apart in a manner to define a slab discharge region having a narrow waveguide axis between the electrodes and a wide axis extending parallel to the electrode surfaces. The resonator is a hybrid design and is a stable, waveguide in the narrow axis, and a negative branch unstable resonator in the wide axis. A pair of mirrors are provided at each end of the electrodes to create a folded beam path in the wide axis. The folded configuration increases the effective length of the resonator which substantially increases the power stability of the laser. The multiple mirror resonator can also be used to increase the width of the discharge region while minimizing spherical aberrations. Each leg of the path has the alignment characteristics of a negative branch unstable resonator so that the alignment of the overall resonator is highly stable.

Abstract: A CO.sub.2 slab waveguide laser (10) is disclosed including a pair of spaced apart electrodes (36,38) having opposed light reflecting surfaces. The electrodes are dimensioned in a manner to guide light in a plane perpendicular to the reflecting surfaces. Light parallel to the reflecting surfaces is not constrained other than by the resonator mirrors (30,32). The resonator structure includes a negative branch unstable resonator in the nonwaveguide dimension. A stable resonator is used in the waveguide dimension but the mirror spacing from the end of the guide is based in part on the configuration of the unstable resonator. A unique support structure is disclosed for maintaining the electrodes in a spaced apart orientation without confining the discharge. Further refinements are disclosed for cooling the laser and for accommodating thermal expansion of the parts. An improved adjustable mirror assembly (26, 28) is provided which allows the tilt angle of the mirror to be varied from outside of the housing.