Abstract: A light source device for pumping a solid-state laser medium of a laser generator, which is compact and capable of economically using LD bars constituting the LD stack with easy maintenance. The light source device is constituted by a plurality of LD modules. Each LD module comprises a plurality of cooling devices on which LD bars are respectively mounted and connection plates on both sides thereof. The LD bars are stacked such that longitudinal directions thereof extend perpendicular to a stacking direction thereof. A desired number of LD modules are mechanically connected with each other using the connection plates to form the LD stack. A sealing member is intervened between confronting connection plates of adjacent LD modules, so that flow passages of coolant formed in the respective LD modules are continuously connected. The connection plates have functions of fixedly supporting the cooling devices of each LD module and electrically connecting the adjacent LD modules.

Abstract: A semiconductor laser device is constructed by stacking an n-cladding layer, an n-optical guide layer, an MQW active layer, a p-cap layer, a p-optical guide layer, a p-cladding layer, an n-current blocking layer, and a p-contact layer in this order on one surface of a transparent substrate. A p electrode is formed on a predetermined region of the p-contact layer. An n electrode having a projected shape is formed on the other surface of the transparent substrate. In this case, a portion, where a projection of the n electrode is arranged, of the device corresponds to the front (a surface on the side of laser light emission) thereof.

Abstract: Normal incidence stack architecture coupled with the development of diode array pumping enables the power/energy per disk to be increased, a reduction in beam distortions by orders of magnitude, a beam propagation no longer restricted to only one direction of polarization, and the laser becomes so much more amendable to robust packaging.

Abstract: The CRCSEL comprises a single-mode optical gain structure and an optically-resonant cavity. The single-mode optical gain structure is structured to generate excitation light having a wavelength and a direction. The optically-resonant cavity is optically coupled to the single-mode optical gain structure and is structured to emit an output light beam in a direction substantially orthogonal to the excitation light. The change in light direction provided by the optically-resonant cavity enables the output light beam to emit from a surface while allowing the excitation light to be generated in a large, high-gain single-mode optical gain structure.

Abstract: A semiconductor laser device includes a substrate having on a surface thereof a semiconductor diode laser portion and a linear amplifier portion. Each of the laser portion and amplifier portion has a waveguide layer with the waveguide layers being in alignment. The laser portion is of a structure which permits it to generate radiation and emit the radiation from one end. The amplifier has an end that receives the radiation from the laser portion, and another end with emits the radiation after the radiation is amplified. The device emits FM radiation but not IM radiation.

Abstract: A nitride semiconductor laser device of high reliability such that the width of contact between a p-side ohmic electrode and a p-type contact layer is precisely controlled. The device comprises a substrate, an n-type nitride semiconductor layer, an active layer, and a p-type nitride semiconductor layer. All the layers are formed in order on the substrate. A ridge part including the uppermost layer of the p-type nitride semiconductor layer of the p-type nitride semiconductor layer i.e., a p-type contact layer is formed in the p-type nitride semiconductor layer. A p-side ohmic electrode is formed on the p-type contact layer of the top of the ridge part. A first insulating film having an opening over the top of the ridge part covers the side of the ridge part and the portion near the side of the ridge part. The p-side ohmic electrode is in contact with the p-type contact layer through the opening. A second insulating film is formed on the first insulating film.

Abstract: A semiconductor laser chip has a semiconductor laser element and a beam shaper integrated into the semiconductor laser chip and serving for shaping a laser beam emitted by the semiconductor laser element.

Abstract: This invention relates to a semiconductor laser device including a semiconductor laser element with an exit surface from which laser radiation can emerge, a collimating lens means which can reduce the divergence of the laser radiation emerging from the exit surface at least with respect to the first direction (Y) which is essentially perpendicular to the exit direction (Z) of the laser radiation the semiconductor laser device furthermore including an auxiliary body which is permanently connected both to the semiconductor laser element and also to the collimating lens means. Furthermore, this invention relates to a semiconductor laser module of a semiconductor laser element, an auxiliary body and a collimating lens means and a process for producing the semiconductor laser means.

Abstract: The average power output of a laser is scaled, to first order, by increasing the transverse dimension of the gain medium while increasing the thickness of an index matched light guide proportionately. Strategic facets cut at the edges of the laminated gain medium provide a method by which the pump light introduced through edges of the composite structure is trapped and passes through the gain medium repeatedly. Spontaneous emission escapes the laser volume via these facets. A multi-faceted disk geometry with grooves cut into the thickness of the gain medium is optimized to passively reject spontaneous emission generated within the laser material, which would otherwise be trapped and amplified within the high index composite disk. Such geometry allows the useful size of the laser aperture to be increased, enabling the average laser output power to be scaled.

Abstract: Light from a first excitation light source is incident on one facet of a first optical fiber. A core is doped with a first rare earth substance. A resonant section induces light resonance in the core to generate resonant light, thereby providing selected light at the other facet of the first optical fiber. An optical multi/demultiplexer reflects the light of the selected wavelength in a direction different from that of the first optical fiber. A second excitation light source supplies light to the resonant section of the first optical fiber via the optical multi/demultiplexer and the other facet of the first optical fiber. A second optical fiber guides the light of the selected wavelength from the optical multi/demultiplexer to an exterior.

Abstract: A rod-shaped solid-state laser apparatus that, in a support structure for the rod-shaped solid-state laser, can generate a stable laser beam. The rod-shaped solid-state laser apparatus includes: a fixing ring, placed around one end of the solid-state laser medium, having part or all of its outer face tapered. A rod holder is placed around the fixing ring, and has a face, facing the fixing ring and tapered at an angle approximately equal to the tapered outer face of the fixing ring. The fixing ring is pressed against the tapered inner face of the rod holder, and also against the solid-state laser medium. The solid-state laser medium is fixed to the rod holder.

Abstract: The laser comprises an active layer (4) with edges cleaved and/or dry etched so that the electromagnetic radiation undergoes total internal reflection. The layer is bounded on one face by a laser substrate (7) and on the other by a Bragg grating having lattices extending in second (11) and first (12) orthogonal directions, each of pitch related to that of the other and to the desired wavelength of the laser. Adjacent the substrate (7) is a heat sink (40), which acts as return path for electrical energy. Adjacent the grating (11, 12) is an electrode layer (24) having a window (26) through which the output laser energy (42) is radiated.

Abstract: A laser apparatus includes a semiconductor laser element having a first active layer made of a GaN-based compound, and emitting first laser light; and a surface-emitting semiconductor element having a second active layer made of a GaN-based compound, being excited with the first laser light, and emitting second laser light. In addition, the surface-emitting semiconductor element may have a first mirror arranged on one side of the second active layer, and a second mirror may be arranged outside the surface-emitting semiconductor element so that the first and second mirrors form a resonator.

Abstract: A semiconductor laser device comprises first current blocking layers formed to define a stripe-shaped current injected region extending in the direction in a front facet from which a laser light is emitted and a rear facet opposing thereto are connected, and a second current blocking layer formed to transverse the stripe-shaped current injected region in the vicinity of the front facet. The first current blocking layers and the second current blocking layer are made of the same layer. Accordingly, a current blocking structure is provided in the vicinity of the facet with the structure which is easily formed, causes no damage on the semiconductor laser device, and minimizes the property degradation, thereby a high facet COD level and high reliability in long-term continuous operations can be achieved.

Abstract: Optically-pumped mid-infrared vibrational-rotational transition gas lasers and amplifiers with improved efficiency and practicality. Inventive laser and amplifier devices include: laser active media comprising a mixture of alkali vapor, selected hetero-nuclear molecular gas, and one or more buffer gases; conventional semiconductor laser diode pump sources with nanometer scale spectral bandwidths; and preferential laser emission in ro-vibrational transitions among relatively low-lying vibrational levels.

Abstract: A solid-state laser crystal constituting a laser-diode-excited solid-state laser apparatus or an optical fiber constituting a fiber laser apparatus or fiber laser amplifier is doped with one of Ho3+, Sm3+, Eu3+, Dy3+, Er3+, and Tb3+ so that a laser beam is emitted from the solid-state laser crystal or the optical fiber, or incident light of the fiber laser amplifier is amplified, by one of the transitions from 5S2 to 5I7, from 5S2 to 5I8, from 4G5/2 to 6H5/2, from 4G5/2 to 6H7/2, from 4F3/2 to 6H11/2, from 5D0 to 7F2, from 4F9/2 to 6H13/2, from 4F9/2 to 6H11/2, from 4S3/2 to 4I15/2, from 2H9/2 to 4I13/2, and from 5D4 to 7F5. The above solid-state laser crystal or optical fiber is excited with a GaN-based compound laser diode.

Abstract: According to the present invention, there is provided a light scattering type particle detector, using a semiconductor laser as a light source, for detecting particles contained in sample fluid which defines a flow path, wherein laser light generated from the semiconductor laser is irradiated to irradiate a region of the flow path with a concave mirror and thereby a particle detecting region is defined. According to the present invention, there is also provided a laser oscillator wherein the optical axis of a semiconductor laser for generating pumping laser light has a predetermined angle with respect to the optical axis of a laser medium for irradiating laser light by pumping. Using such a laser oscillator, laser light irradiated from the laser oscillator is condensed to irradiate a region of a flow path defined by sample fluid, and thereby a particle detecting region is defined. Particles contained in the particle detecting region are detected by receiving scattered light with a light receiving portion.

Abstract: A laser device for producing laser radiation at an eyesafe wavelength from a diode-pumped solid-state laser. The device consists of three stages. The first stage is a laser diode whose output pumps the second stage. The second stage is a guided-wave laser or guided-wave Raman-shifted laser whose output pumps into the upper laser level of the Erbium laser dopant of the third stage. The third stage is an Erbium-doped solid-state crystalline-host laser whose output wavelength is in the eyesafe region. One embodiment of the device is: a cw laser diode with a wavelength in the range 0.9 to 1.0 microns, which pumps a guided-wave laser doped with Ytterbium and Erbium that produces laser output with a wavelength near 1.5 microns, which further pumps an Erbium-doped crystal laser that produces laser output with a wavelength in the eyesafe region near 1.6 microns.

Abstract: A semiconductor laser device according to the present invention comprises a laminated structure of a semiconductor material including an active layer formed of a quantum well structure, a low-reflection film formed on one end face of the structure, and a high-reflection film formed on the other end face of the structure. The cavity length (L) of the device is 1,200 &mgr;m or more. This laser device, which enjoys high kink currents and a satisfactorily linear current-optical output characteristic, is a useful pumping light source for optical fiber amplifier.

Abstract: The solid-state laser gyro of the invention comprises a solid-state resonator block, in which an optical path followed by two counterrotating waves generated by an optical-gain laser medium is defined, and, according to an important characteristic, the gain medium is attached to the resonator and is made of a rare-earth-doped crystal.

Abstract: The invention relates to a method using dry etching to obtain contamination free surfaces on of a material chosen from the group comprising GaAs, GaAlAs, InGaAsP, and InGaAs to obtain nitride layers on arbitrary structures on GaAs based lasers, and a GaAs based laser manufactured in accordance with the method. The laser surface is provided with a mask masking away parts of its surface to be prevented from dry etching. The laser is then placed in vacuum. Dry etching is then performed using a substance chosen from the group containing: chemically reactive gases, inert gases, a mixture between chemically reactive gases and inert gases. A native nitride layer is created using plasma containing nitrogen. A protective layer and/or a mirror coating is added.

Abstract: Disclosed herein is a diode-pumped solid state (DPSS) laser having a laser rod and a diode array, located proximate the laser rod. In one embodiment, the diode array includes a plurality of high power diode bars spaced along the diode array, where each is configured to emit radiation therefrom. In addition, in this embodiment, the spacing of the high power diode bars and the location of the diode array with respect to the laser rod are selected to allow the laser rod to receive the radiation from the high power diode bars in a substantially uniform distribution. In addition, a method of manufacturing a DPSS laser, and a DPSS laser assembly are also disclosed.

Abstract: A laser apparatus includes a semiconductor laser element, a surface-emitting semiconductor element including a first mirror, a second mirror, and a modulation unit. The semiconductor laser element emits first laser light having a first wavelength. The surface-emitting semiconductor element is excited with the first laser light, emits second laser light having a second wavelength which is longer than the first wavelength. The first mirror in the surface-emitting semiconductor element is arranged on one side of the first active layer. The second mirror is arranged outside the surface-emitting semiconductor element so that the first and second mirrors form a resonator in which the second laser light resonates. The modulation unit modulates the surface-emitting semiconductor element.

Abstract: A diode-pumped microlaser in accordance with the present invention includes a diode pump, a first lens, a second lens and a laser glass. The diode pump generates an input pump beam. The first lens and second lens manipulate the pump beam by collimating the pump beam in focal planes that are perpendicular to each other. The laser glass receives the manipulated pump beam from the second lens and converts the pump beam into a laser beam. The laser glass is further doped with predetermined amounts by weight of Erbium and Ytterbium to ensure that an output laser beam with an eyesafe wavelength is generated. The microlaser further includes a passive Q-switch made of a Cobalt-spinel material, which receives the output laser beam and generates laser pulses using passive switching techniques, independent of any external temperature control. This configuration allows the microlaser to function as a laser rangefinder over extended temperature ranges in a manner that is eyesafe to the user.

Abstract: A semiconductor-laser-excited solid-state laser apparatus includes a solid-state laser element and a semiconductor laser unit including a resonator. The solid-state laser element is excited by light emitted from the semiconductor laser unit, and emits laser light. The resonator length in the semiconductor laser unit is arranged to be at least 0.8 mm, so as to reduce an amount of wavelength shift in light emitted from the semiconductor laser unit, and achieve a stable, high-power laser output from the semiconductor-laser-excited solid-state laser apparatus.

Abstract: A method for modulating the output of an optically pumped, tunable VCSEL. Two approaches are disclosed. In a first approach, the output of the VCSEL is modulated by modulating the pump laser. In a second approach, the output of the VCSEL is modulated by modulating a voltage applied across the active region.

Abstract: An optically pumped laser has a gain medium positioned inside of an optical resonator cavity and disposed about a resonator optical axis. An optical pumping source is positioned outside of the optical resonator cavity. A reflective coupler with a coupler body, and an interior volume passing therethrough is positioned proximal to the optical pumping source. Light from the pumping source passes into an entrance aperture of the reflective coupler to an exit aperture of the reflective coupler positioned distal to the optical pumping source. The interior volume of the reflective coupler is bounded by a reflective surface, an entrance aperture and the exit aperture, and is substantially transparent to radiation from the optical pumping source. The reflective surface has a high reflectivity matched to radiation from the optical pumping source.

Abstract: A single semiconductor laser device used in a semiconductor laser module of an optical amplifier and having a first light emitting stripe with a diffraction grating and at least one other light emitting stripe with a diffraction grating and which are aligned to respectively emit a first laser beam and at least one other laser beam through one edge surface.

Abstract: A diode end-pumped solid state laser is provided which produces improved power output, long term stability and improved conversion efficiency from the pumping power, high as well as low power operation while maintaining certain desirable common characteristics such as TEM00 operation, circular outputs, readily aligned systems and compatibility with long lifetime for all components. The invention intracavity conversion to second, third and higher harmonics in several different spectral regimes. The invention also addresses the aspects of design flexibility, seeking in certain embodiments to provide a single platform for providing several harmonic beams.

Abstract: An optical membrane device and method for making such a device are described. This membrane is notable in that it comprises an optically curved surface. In some embodiments, this curved optical surface is optically concave and coated, for example, with a highly reflecting (HR) coating to create a curved mirror. In other embodiments, the optical surface is optically convex and coated with, preferably, an antireflective (AR) coating to function as a refractive or diffractive lens.

Abstract: Disclosed herein is a color laser display that comprises a red laser light source for emitting red laser light, a green laser light source for emitting green laser light, and a blue laser light source for emitting blue laser light. An excitation solid laser unit (which has a solid-state laser crystal doped with Pr3+ and a GaN semiconductor laser element for exciting the solid-state laser crystal), a fiber laser unit (which has a fiber with a Pr3+-doped core and a GaN semiconductor laser element for exciting the fiber), or a semiconductor laser unit (which has a semiconductor laser element, employing a GaN semiconductor, and a surface-emitting semiconductor element), is employed as at least one of the red laser light source, the green laser light source, or the blue laser light source.

Abstract: Disclosed is a side pumping type DPSS (Diode Pumped Solid-State) laser having a high efficiency of pumping light together with a large output of the laser power. The DPSS laser includes a first laser chip for generating a pumping light, a second laser chip provided at a predetermined degree to be slightly slanted, although being parallel with the first laser chip, so as to avoid a contact with the pumping light, a first and second focusing lens for focusing the pumping lights, and a side pumping medium for forming the focused pumping lights in a beam mode so as to output as a lasing light.

Abstract: A solid-state laser rod pumping module comprises a stack-type semiconductor laser including a plurality of bar-shaped (or rectangular) components that are stacked in a direction parallel to the axis of a solid-state laser rod, each of the plurality of bar-shaped components including a plurality of laser-light-emitting portions that are aligned and integrated in a direction orthogonal to the axis of the solid-state laser rod. The stack-type semiconductor laser has a large divergence angle in a longitudinal parallel to the axis of the solid-state laser rod.

Abstract: A thin, planar laser material is bonded to a light guide of an index-matched material forming a composite disk. Diode array or other pump light is introduced into the composite disk through the edges of the disk. Pump light trapped within the composite disk depletes as it multi-passes the laser medium before reaching an opposing edge of the disk. The resulting compound optical structure efficiently delivers concentrated pump light and to a laser medium of minimum thickness. The external face of the laser medium is used for cooling. A high performance cooler attached to the external face of the laser medium rejects heat. Laser beam extraction is parallel to the heat flux to minimize optical distortions.

Abstract: A diode pump, solid state laser deep UV laser source is described for customized ablation in photo-refractive surgery. The solid-state deep UV laser source is tailored to have a pulse repetition rate of about 1 kHz and a relatively small spot size at both positions of the cornea and the scanner. Such a deep UV laser source enables the use of fast scanner and the implement of fast eye tracker. One embodiment of such a deep UV laser source comprises a passively Q-switched microchip laser, a diode-pumped multiple pass amplifier, and a wavelength converter.

Abstract: An optically active waveguide laser (30) includes a multimode portion (126) for carrying more than one spatial mode at a predetermined wavelength chosen from a bandwidth including a pump wavelength (64) and the lasing wavelength (66). The multimode portion (126) has a first refractive index. A cladding portion (386) is proximate the multimode portion (126). A multimode grating (60, 56, or 62) is written on at least one section (26) of the multimode portion for reflecting the predetermined wavelength.

Abstract: Apparatus and method for stabilizing the wavelength of a tunable laser to a target wavelength, by correspondingly adjusting the electrooptical performance of the laser's gain medium, whereby to eliminate the frequency shift due to vibrational factors. The electrooptical performance of the laser's gain medium is adjusted, in the case of an electrically pumped laser, by changing the injection current used to pump the laser; and the electrical performance of the laser's gain medium is adjusted, in the case of an optically pumped laser, by changing the intensity of the pump laser used to energize the laser. The system is implemented with a feedback mechanism.

Abstract: A conventional method for a solid-state laser device that obtains a laser beam output of a high quality at a high output using a laser diode as a pumping light source has a problem that the costs are increased and the fabrication becomes complicated due to an increasing number of components, such as a diffusing reflection mirror, a condenser lens, and a holding mechanism and a cooling mechanism thereof. Coating with a antireflection coating to reduce a transmission loss of laser diode light, and coating with a high reflection coating to reflect the laser diode light are provided alternately on the outer surface of a cooling tube. Also, an irradiation direction of the laser diode is not directed to the center of the laser rod, but is given with a certain angle to be positively tilted. This configuration makes it possible to eliminate the above problem.

Abstract: Systems and methods for enhancing the stability of a mode-locked laser's output are disclosed. The laser systems include a mode-locking element that mode-locks the laser's output, and a semiconductor element. The semiconductor element produces a loss at the laser's operative wavelength that increases as pulse energy increases, thereby enhancing the stability of the mode-locked output. The semiconductor elements can be used to enhance stability of both passively and actively mode-locked laser systems.

Abstract: A solid-state laser rod pumping module has a stack-type semiconductor laser including a plurality of bar-shaped components that are stacked in a direction parallel to the axis of a solid-state laser rod. Each bar-shaped component includes a plurality of laser-light-emitting portions that are aligned and integrated in a direction orthogonal to the axis of the solid-state laser rod. The large divergence angle of the stack-type semiconductor can be compensated by including a light focusing component for focusing laser light emitted out of the stack-type semiconductor laser. The focused light is guided by a laser light guiding component disposed in a diffusive reflection tube. A light guiding component guides the focused light onto a solid-state laser rod located within the diffusive reflective tube, while maintaining the length of one side of the cross section of the guided light.

Abstract: A method of controlling a unipolar semiconductor laser in the 4-12 &mgr;m mid-infrared range. This is an optical control method, unlike a purely electrical, power control method which injects a relatively large flux of electrons. The optical control method may advantageously include two optical beams of the same wavelength and a device for making those beams interfere in the active layer of the laser, the optical control beams having a much shorter wavelength than the wavelength of the unipolar laser and having a frequency capable of being modulated more rapidly than that of the laser.

Abstract: A passively mode-locked optically pumped semiconductor vertical-external-cavity surface-emitting laser (OPS-EXSEL) is disclosed. The laser is mode locked by a semiconductor saturable absorber mirror (SESAM) which forms part of an external cavity. Both the beam-quality limitations of edge-emitting lasers, and the power restrictions of electrically pumped surface-emitting lasers are overcome. The laser uses a semiconductor wafer in which a stack of quantum wells is grown adjacent to a single Bragg-mirror structure. Light from one or more multi-mode high-power diode lasers is focused onto the face of the wafer and pumps the wells by absorption in the barrier regions. The area of the laser mode on the active mirror can be about 104 times larger than the mode area on the facet of an edge-emitting laser, offering scope for the generation of high average power and large pulse energy. At the same time the external cavity enforces fundamental mode operation in a circular, near-diffraction-limited beam.

Abstract: A pump laser capable of delivering at least a specified amount of output power is described. The pump laser has an array of N semiconductor lasers each having a first wavelength and an individual available output power (P) such that the product of N times P is equal to or greater than the specified amount of output power. The pump laser also has a coupler configured to couple light emitted by the individual lasers in the array to an individual optical fiber.

Abstract: A solid state laser excited by a semiconductor laser can generate a stable and highly efficient high power laser beam. The laser apparatus includes a solid state laser element containing an active medium, a semiconductor laser for optically exciting the solid state laser element, a power supply for supplying pulses of current having magnitudes that change with time during each pulse to the semiconductor laser, and an optical resonator for emission of a laser beam from the solid state laser element. When the semiconductor laser is driven with the pulses that change in magnitude during each pulse, it produces pulsed excitation light that excites the solid state laser element. A stable laser beam is produced because changes in thermally sensitive light-generating parameters of the semiconductor laser are compensated.

Abstract: Laser light emitted from an LD apparatus is concentrated and applied onto a laser light path region A of a slab-shaped YAG crystal 21 and the neighborhood thereof with the use of a concave lens and a pair of reflecting mirrors, a duct lens, or a plurality of cylindrical lenses, whereby a concentrated applied light intensity distribution in the side surface width direction (y-axis direction) of the slab-shaped YAG crystal is formed as a double-peak distribution having maximum values P1 and P2 at opposite end portions A1 and A2 of the laser light path region of the slab-shaped YAG crystal or in the neighborhoods thereof.

Abstract: According to the invention, a device for emission of light is made comprising an emitting structure (22) comprising an active part (4), and a micro-cavity, delimited by mirrors (14, 20). and containing the active part, and a laser diode (26) designed for pumping the emitting structure. The emitting structure is fixed to the laser diode. The invention is particularly applicable to the detection of gas.

Abstract: The invention features an edge-emitting semiconductor signal laser having an active region to produce laser light. There is provided a semiconductor pump laser monolithically integrated with the edge-emitting signal laser. The pump laser includes a photon emissive active region to provide photopumping of the active region of the edge-emitting signal laser, thereby providing optical excitation of the active region of the signal laser.

Abstract: A solid-state laser apparatus includes a cavity 17 for storing a laser diode 40 and a laser medium 6 to be excited by the laser diode 40, and a storage unit 70, for communicating with the cavity 17 and for internally storing a drying agent 71. A moisture permeable film 72 is formed at openings 73 whereat the cavity 17 and the storage unit 70 communicate with each other.

Abstract: A semiconductor laser device, comprising a semiconductor laser array for excitation having a plurality of semiconductor laser elements, and an optical resonator having a solid-state laser medium with a reflection mirror formed on one end surface and an output mirror provided in parallel to the reflection mirror, wherein laser beams emitted from the plurality of the semiconductor laser elements enter the optical resonator independently from each other, and the laser beams are respectively amplified and are projected by the optical resonator.

Abstract: A laser wherein pump radiation from laser diodes is delivered to a pump chamber and into the lasing medium by quasi-three-dimensional compound parabolic concentrator light channels. The light channels have reflective side walls with a curved surface and reflective end walls with a curved surface. A flow tube between the lasing medium and the light channel has a roughened surface.