Abstract: The use of rectangular cross-section gain material with two or more cylindrical lenses placed in close proximity or attached to opposite sides of the gain material allows for an efficient pumping of the gain material in an optical gain component. The optical gain component can be used in a laser device. Laser diode bars are arranged so as to pump the gain material through the lenses. A cooling apparatus can cool a rectangular cross-section gain material through two opposite flat sides so that no thermal birefringence is created. An optical gain component with two gain materials can orient these two gain materials such that the small-signal gain is almost circular and gaussian in profile with a large center peak tapering off to a much lower gain at the edges.

Abstract: A system for generating an ultra short optical pulse by pumping a semiconductor signal laser with an optical pulse from a semiconductor probe laser. The signal laser has dual segments each operated under different d.c. injection current levels. The probe laser is modulated with a pulsed input and the optical output thereof is coupled via optical means to the signal laser so as to Q-switch the latter. Optical pulses in the 65 ps range result.

Abstract: A laser package is designed for large scale assembly by machinig a piec3 part of relatively large dimensions where the part has a slot for holding a laser. The piece part is mounted on heatsink of like dimensions. A second piece part includes an elongated groove for holding a fiber lens plate where the second piece part is mounted against the edge of the heat sink such that the lens is properly aligned with the laser. Thus, the critical alignment of the laser and the fiber is achieved by the alignment of like dimensioned piece parts of relatively large dimensions.

Abstract: A multiwavelength upconversion waveguide laser producing visible or ultraviolet wavelength radiation comprising a semiconductor laser diode producing relatively long wavelength radiation, a channel waveguide having a thin film material which converts the relatively long wavelength radiation into visible or ultraviolet wavelength radiation, and a optical resonator which recirculates the visible or ultraviolet wavelength radiation. The optical resonator may use an output optical coating or one or more Bragg grating reflectors as an output coupler. One or more optical resonators may be used to produce one or more visible or ultraviolet radiation wavelengths. One or more independently controllable lightwave modulators are used to modulate the visible or ultraviolet wavelength radiation.

Abstract: A semiconductor laser power build-up system includes a semi-conductor laser. An optical resonance cavity is defined between at least two reflective elements and has an intracavity light beam along an intracavity beam path. A return light beam, which is a portion of the intracavity light beam, is transmitted through one of the reflective elements and is coincident with but oppositely directed relative to the incident beam. The laser is wholly optically locked to the cavity and the intracavity beam passes substantially without loss within the cavity. In a preferred application, a sample is placed in the cavity and a detector is provided to sense chemicals in the sample by, for example, detecting Raman-scattered light. A wavelength-determining element such as a grating or an etalon is preferably in the incident beam path between the laser and the cavity.

Abstract: A high efficiency, diode pumped laser includes a resonator mirror and an output coupler which define a nearly confocal resonator. Positioned in the resonator is a laser crystal. A diode pump source supplies a pump beam to the laser crystal and produces an output beam. A strong thermal lens transforms a non-confocal resonator to a nearly confocal resonator. The TEMOO mode diameter in the laser crystal may be smaller than the pump beam diameter that is incident on the laser crystal. Output powers greater than about 4 W are achieved, the overall optical efficiency is greater than about 25%, and an optical slope efficiency in a TEMOO mode of greater than 40% is possible.

Abstract: A gain medium is disposed between two mirrors to form a resonant cavity. The cavity length is selected so that the gain bandwidth of the gain medium is less than or substantially equal to the frequency separation of the cavity modes and such that a cavity mode frequency falls within the gain bandwidth. A nonlinear optical material is disposed either inside or outside the cavity to generate new laser wavelengths. The nonlinear optical material may be contained in a cavity which is resonant at the microchip laser frequency. Alternatively, the microchip laser may be tuned, for example thermally or by the application of a longitudinal or transverse stress, to the frequency of the resonant cavity. The laser is optically pumped by any appropriate source such as a semiconductor injection laser or laser array. Suitable gain media include Nd:YAG, Nd:GSGG and Nd pentaphosphate, and suitable non-linear optical material include MgO:LiNbO.sub.3 and KTP.

Abstract: A housing for a slab laser gain media with a rectangular cross section which provides for a uniform flow of coolant over the slab top and bottom surfaces (18) and (20), while insulating the slab side surfaces (14) and (16). The slab gain media is bonded between two tabs at each end of the housing (48a, 48b, 50a, 50b). The slab top and bottom surfaces are made level with the tab top and bottom surfaces. Seals are placed on the continuous surface formed by the slab top and bottom surfaces and the tab top and bottom surfaces, thus sealing the ends of the housing, and also surrounding the coolant inlets and outlets. Windows (32) and (34) are then placed on top of each seal to form two thin cavities confining the coolant to flow across the slab top and bottom surfaces (18) and (20), and allowing for the close-coupling of either one or two pump sources, such as a two dimensional laser diode array assembly (58) and (60).

Abstract: A room-temperature solid state laser for producing an output laser emission t any wavelength within a preselected range of wavelengths is disclosed.

Abstract: A spectral narrowing of the output bandwidth from a laser array is obtained by feeding back to the array a portion of its emitted light, while outputting the remainder of the light emitted from the array. An optical system to accomplish this preferably includes a pair of lenses, together with a diffraction grating that can be positioned either in-line with the laser array and lenses, or in a side-arm along with one of the lenses. The lenses can be set up so that light from each laser element is fed back either to itself, or to a symmetrically located element on the opposite side of the system axis. For a multi-lobe output from the laser array, one of the lobes is used for feedback and the others as outputs, resulting in a narrowing of the output angular divergence as well as of the output bandwidth.

Abstract: An 850 nm laser and/or amplifier comprises a single mode fluoro-zirconate optical fibre (20) doped with Er.sup.3+. CW operation of the normally self-terminating lasing transition .sup.4 S.sub.3/2 to .sup.4 I.sub.13/2 is achieved by applying excitation energy at 801 nm which both maintains a population inversion between the lasing levels and also populates the upper lasing level by a two-stage process of excitation to the .sup.4 I.sub.9/12 level from the .sup.4 I.sub.15/2 ground state and then to .sup.2 H.sub.9/2 level by ESA.

Abstract: A tunable ytterbium-doped solid-state laser has a laser cavity defined a r of mirrors, a laser medium positioned in this cavity, means for pumping the laser medium, and means for tuning the output of this laser medium to a selected wavelength within a wavelength range. The laser medium has a host material doped with enough ytterbium ions to produce a longitudinal mode laser emission when the laser medium is pumped. In a most preferred embodiment, the laser emission is frequency-doubled and tuned to a wavelength corresponding to a Fraunhoffer line in the solar spectrum.

Abstract: A radiation wavelength conversion device is implemented in the form of a waveguide that includes a single crystal halide-based cladding layer, and a halide-based active layer. The active layer has a greater refractive index than the cladding layer, is approximately lattice matched with the cladding layer, and includes a dopant that causes it to respond to input radiation at one wavelength by emitting radiation at a different wavelength. The active layer can either form part of a laser resonator cavity, or can operate through spontaneous emission. It is preferably about 3.5-5 microns thick to induce single-mode propagation, and can be divided into separate waveguiding channels to limit beam fanning. The device is operable at room temperature, and can be fabricated using conventional microelectronics techniques.

Abstract: A laser generating apparatus provided with the following is disclosed. That is to say, a rod shaped laser medium for receiving excitation light irradiation and emitting laser light having a prespecified wavelength, a reflecting tube having a central axis and possessing a rotating surface and two end surfaces, wherein an inner surface is made a reflecting surface, and the rod shaped laser medium is stored therewithin, and a virtual light source formation mechanism for forming an excitation virtual light source which can be construed as a point light source or a line light source, in the vicinity of the central axis. By means of this, a virtual light source having an energy distribution concentrated in the central part is formed, and it is possible to increase excitation efficiency.

Abstract: Light beams output from active layer stripes of a semiconductor laser array are individually collimated in a GRIN lens array and are converged, in a aspheric lens, into a beam spot, to thereby end-pump a solid state laser with high efficiency.

Abstract: A gain medium is disposed between two mirrors to form a resonant cavity. The cavity length is selected so that the gain bandwidth of the gain medium is less than or substantially equal to the frequency separation of the cavity modes and such that a cavity mode frequency falls within the gain bandwidth. A nonlinear optical material is disposed either inside or outside the cavity to generate new laser wavelengths. The nonlinear optical material may be contained in a cavity which is resonant at the microchip laser frequency. Alternatively, the microchip laser may be tuned, for example thermally or by the application of a longitudinal or transverse stress, to the frequency of the resonant cavity. The laser is optically pumped by any appropriate source such as a semiconductor injection laser or laser array. Suitable gain media include Nd:YAG, Nd:GSGG and Nd pentaphosphate, and suitable non-linear optical material include MgO:LiNbO.sub.3 and KTP.

Abstract: A semiconductor-laser-pumped solid-state laser apparatus having a semiconductor laser device, a solid state laser medium, and laser resonators. The semiconductor laser device has a plurality of emission points which are arranged on a straight line and from which pump light is generated. The laser resonators are disposed in correspondence with the emission points. A plurality of solid state laser beams can be generated by using one solid state laser medium.

Abstract: A high-output, single fundamental transverse mode solid state laser is disclosed which uses a semiconductor laser array as an excitation light source. The solid state laser comprises: a laser element which includes a core containing an element added as a laser medium, a cladding containing no such laser medium element, and reflecting mirrors coated over the cladding surface for repeatedly reflecting incident excitation light so that it may repeatedly pass through the core; an excitation light source formed by semi-conductor laser or light emitting diode array; means for guiding the excitation light from the excitation light source to one side of the laser element for incidence thereto; and a resonator for the oscillation of the solid state laser.

Abstract: A laser-diode-pumped solid-state laser includes a solid-state laser rod which is doped with a rare-earth material such as neodium and has a wavelength converting function and a semiconductor laser which pumps the solid-state laser rod. Opposite end faces of the solid-state laser rod are formed into resonator mirrors, and a wavelength-converted wave such as a second harmonic of the laser beam oscillated by the solid-state laser rod or a sum frequency wave of a laser beam oscillated by the solid-state laser rod and a semiconductor laser beam emitted by a semiconductor laser is extracted.

Abstract: A laser light beam generating apparatus includes a laser diode, a laser medium, a non-linear optical crystal element, reflecting mirrors, a deflecting mirror, a temperature-control device and a case. The laser diode emits at least one pumping laser light beam. The laser medium is excited by the pumping laser light beam from the laser diode. The non-linear optical crystal element is arranged in outputted light path of the pumping laser light beam from the laser diode. The reflecting mirrors constitute a resonator with the laser medium and the non-linear optical crystal element. The deflecting mirror deflects the light path of the light beam from the resonator. The temperature-control device controls the temperature of the laser diode and the resonator. The case houses the laser diode, the laser medium, the non-linear optical crystal element, the reflecting mirrors, the deflecting mirror, and the temperature-control device.

Abstract: A plurality of linear arrays of lasers are configured into an area array by optical coupling to a linear-to-area array by optical coupling to a linear-to-area fiber optic bundle. The linear face of the bundle is coupled to the linear array of lasers. By activating all the lasers simultaneously or selectively, a single high power output or high intensity signals at discrete addresses in the area face of the bundle are achieved respectively. Applications for high power, two dimensional laser devices, high definition display, solid state laser pumping and others are achieved.

Abstract: A carrier for a laser diode bar comprises a generally rectangularly shaped block formed from a dielectric material having a high thermal conductivity. The block includes a stepped recess formed therein having a height essentially equal to one half the height of a laser diode bar to be mounted thereon. An assembly for mounting a laser diode bar comprises a pair of carriers in contact with one another and oriented such that their stepped recesses are in facing relationship to one another. A laser diode bar is positioned between the carriers in the space left by their combined stepped recesses. A plurality of assemblies may be placed in contact with or separated from one another.

Abstract: A laser system uses a high-power diode laser in cooperation with a nonimaging concentrator to end pump a relatively thin, solid-state, highly doped lasant. The laser system generates a very high density of excited ions in the lasant mode volume to produce high peak power pulses having comparable magnitudes over a wide range of pulse repetition frequencies.

Abstract: A thermally conducting reflecting envelope for use in laser cavities, and laser apparatus employing such envelopes. A transparent heat conducting member, such as sapphire, surrounds a laser medium and has a transmissive coating thereon that transmits pump light provided by a pump light source onto the laser medium. The coating reflects the diode pump light and transmits laser light to suppress ASE that causes clamping of the laser output at a relatively low level. An absorbing elastic material is disposed on the dielectric coating and is adapted to absorb the laser light. Heat sinks are disposed in contact with the absorbing elastic material, and conducts heat away from the laser medium. A light entrance window or area is antireflection coated to transmit the pump light onto the laser medium. A liquid cooled version further includes a liquid cooling channel disposed between the laser medium and the thermally conducting member.

Abstract: A high-power semiconductor diode laser or array of semiconductor diode lasers (14) optically end-pumps a compact, tunable, solid-state laser (28) with a pumping beam (74) well-matched to the absorption bandwidth and mode volume (78) of the solid-state laser (28). Tilted birefringent plates (210) positioned within the solid-state resonator cavity (16) are employed to control the spectral bandwidth and wavelength output of the waveguide pumping beam (204). Infrared output (100) generated by such a solid-state laser (28) is coupled into a nonlinear waveguide (200) and converted to visible output (206) through the process of second-harmonic generation.

Abstract: A novel diode bar, side-pumped laser cavity design having high optical to optical conversion efficiency and a high slope efficiency is provided. A slab geometry with a single, high angle of incidence internal reflection permits gain to be accessed near the pump face of a laser material which absorbs strongly at the pump wavelength.

Abstract: In an optical wavelength converting apparatus, a fundamental wave impinges upon a crystal of a nonlinear optical material, the type II of phase matching between the fundamental wave and its second harmonic is effected, and the second harmonic of the fundamental wave is thereby radiated out of the optical wavelength converting apparatus. Two crystals constituted of the same material are employed as the crystal. The two crystals have equal lengths and are located in orientations such that corresponding optic axes may be shifted 90.degree. from each other. The optical wavelength converting apparatus yields the second harmonic having the maximum possible output power and yet can be kept small in size and low in cost.

Abstract: In a solid-state laser device comprising a solid-state laser medium disposed in a laser resonator and a semiconductor laser device for exciting the solid-state laser medium, the solid-state laser device comprises a vessel for receiving the solid-state laser medium and the semiconductor laser device. The vessel is filled with a refrigerant so that the refrigerant is contact with at least one part of the semiconductor laser device and at least one of the solid-state laser medium. Connected to the vessel, a temperature controlling device controls temperature of the refrigerant to maintain a predetermined desired temperature so that the excitation laser beam has an excitation wavelength which coincides with an absorption wavelength of the solid-state laser medium. The refrigerant may composed of an insulated transparent liquid or an inert gas.

Abstract: A laser apparatus or system is provided including a driving mechanism for driving a pulsed semiconductor laser which injects optical energy into a lasing medium. A digital filter is employed to adjust the time duration or pulse width of drive pulses which excite the semiconductor laser. In this manner, the irradiation of the lasing medium is adjusted by pulse width modulation of the driving current in the semiconductor laser. The laser apparatus employs a sampled output, digitally filtered, negative feedback signal to drive the semiconductor laser. This structure has the effect of making the semiconductor laser responsive to changes in the laser system or to undesired degradation in the laser system. The laser apparatus compensates for the inherent time lag in laser output power energy during initial startup of the laser.

Abstract: A laser light generating apparatus of the invention comprises an exciting light source (1) for generating a plurality of exciting laser beams, a laser medium (7) for generating at least two laser beams with radiation of the plurality of exciting laser beams at different positions thereof, reflecting means (8) for reflecting at least a part of the laser beams generated from the laser medium (7) and constructing a laser resonator (5) with thermal lenses (7a) through (7d) formed within the laser medium (7), and phase-compensating means (9) for compensating a phase of a laser beam from the laser resonator (5). Therefore, the laser generating apparatus becomes able to generate a laser beam whose energy is much concentrated within a small divergent angle. Furthermore, it becomes possible to control the laser beam in tracking by changing a phase-compensating amount of the phase-compensating means.

Abstract: Apparatus for end-pumping of a solid-state laser with a source of high optical brightness. A stack of diode laser bars are excited, and each bar emits a light beam of a selected pump wavelength in a chosen direction. The light beam output of the diode bar stack is divided into a plurality of smaller, approximately rectangular light beams, which serve as extended light sources, by a plurality of mirrors that are positioned to receive one or more of these smaller beams and redirect such beams onto first, light-receiving ends of one or more optical fibers. Light collection optics receive the beams issuing from the mirrors and focus these beams onto a light-receiving end of an optical fiber with beam convergence angles that are appropriate for the numerical aperture of that fiber.

Abstract: Novel solid state gain mediums provide monolithic lasers with short cavity lengths and with the ability to efficiently lase in the lowest order TEM.sub.00 mode. Unoptimized optical power conversion efficiency of 35% has been achieved with the novel solid state gain mediums in monolithic lasers that have a cavity length as short as 0.5 mm. With proper values for the output mirror reflectivity and low loss host crystals, the optical power conversion efficiency is approximately 50%. Moreover, when in optical contact with a frequency doubling optically non linear crystal, the novel solid state gain mediums in the monolithic lasers can produce coherent visible light.

Abstract: An improved housing for use in a laser pump module, including a laser rod housed within a sleeve and laser diodes providing the rod excitation, wherein the main housing structure is constructed from a single piece of material and formed with internal interconnected internal passageways to provide for efficient cooling of the pump sources and the sleeve provides the outer wall of the coolant passage for cooling of the laser rod.

Abstract: A laser-diode-pumped solid-state laser includes a semiconductor laser for emitting a pumping laser beam, a solid-state laser crystal of an ion crystal of a paramagnetic substance doped with neodymium, for producing a laser beam in response to being pumped by said pumping laser beam, a resonator for oscillating the laser beam produced by said solid-state laser crystal, and an optical wavelength converter in said resonator for converting the wavelength of the oscillated laser beam into another wavelength. The solid-state laser crystal has a neodymium ion concentration higher than 3 at %. The solid-state laser oscillates stably in a single longitudinal mode at all times to produce a highly intensive laser beam of short wavelength.

Abstract: The present invention is the use of coupled quantum wells in the active region of a semiconductor laser to modulate the frequency and amplitude of the light output of the laser. In a particular embodiment of the present invention the coupled quantum wells are contained in a graded index of refraction semiconductor double heterostructure laser. The active region of this tunable laser consists of two quantum wells having a width of approximately 50 Angstroms or less which are separated by a barrier layer having a width of approximately 20 Angstroms or less. The quantum well material is intrinsic GaAs and the barrier layer is Al.sub.x Ga.sub.1-x As wherein x=0.23. The active region is surrounded by the double heterostructure in which one side is doped p-type and the second side is doped n-type. The resulting laser is a p-i-n type structure.

Abstract: Efficient, low threshold laser emission from a laser crystal doped with chromium and neodymium ions is obtained when pumped by visible laser diodes in the range of 610 nm to 680 nm. A typical laser Cr,Nd:GSGG crystal having an extraordinarily broad absorption bandwidth allows high pump efficiencies when using visible laser diodes, particularly in comparison to the Nd:YAG laser. The broad absorption bandwidth tolerance of the Cr,Nd:GSGG crystal to the pumping wavelengths allows visible diode pumping of the neodymium transition without regard to the wavelength of the visible diodes. Longitudinal or end-pumping to take advantage of the emission properties of the visible laser diodes, a nearly hemispherical laser resonator configuration and other co-doped Cr,Nd laser host materials are disclosed. Consequently, costs are reduced for the semiconductor pump as well as producing a compact, efficient, lightweight and reliable laser previously unachievable with other types of laser or lamp pumping.

Abstract: A high efficiency pumping scheme mode matches the TEMOO laser mode volume with a plurality of linearly spaced laser diode pumping sources positioned along a lateral side of a block of laser material. The cavity resonator within the block is configured in a tightly folded zig-zag configuration. Pump radiation from the diode pumping sources is collimated by an optical fiber and the fold angle is selected to mode match the pump radiation to the mode volume.A laser oscillator is followed by one or more cascaded amplifier stages including a block of laser material arranged in a tightly folded zig-zag configuration. Pump radiation from the diode pumping sources is collimated by an optical fiber and the fold angle is selected to mode match the pump radiation to the mode volume.

Abstract: In a solid-state laser device which emits an output laser beam by pumping a solid-state laser medium in a laser resonator by an excitation laser beam generated from a semiconductor laser unit, both the solid-state laser medium and the laser resonator are mounted on a common thermal conductive support which is thermally controlled by a temperature controller through a Peltier effect element to keep a temperature of the thermal conductive support substantially constant. A thermistor is attached to the thermal conductive support to detect the temperature of the support and to supply the temperature controller with a temperature detection signal representative of the temperature of the support. The temperature controller carries out proportional-plus-integral-plus-derivative control to supply a control signal to the Peltier effect element.

Abstract: A gain medium is disposed between two mirrors to form a resonant cavity. The cavity length is selected so that the gain bandwidth of the gain medium is less than or substantially equal to the frequency separation of the cavity modes and such that a cavity mode frequency falls within the gain bandwidth. A nonlinear optical material is disposed either inside or outside the cavity to generate new laser wavelengths. The nonlinear optical material may be contained in a cavity which is resonant at the microchip laser frequency. Alternatively, the microchip laser may be tuned, for example thermally or by the application of a longitudinal or transverse stress, to the frequency of the resonant cavity. The laser is optically pumped by any appropriate source such as a semiconductor injection laser or laser array. Suitable gain media include Nd:YAG, Nd:GSGG and Nd pentaphosphate, and suitable non-linear optical material include MgO:LiNbO.sub.3 and KTP.

Abstract: In a solid-state laser device which pumps a solid-state laser medium in a laser resonator by an excitation laser beam generated from a semiconductor laser unit and which emits an output laser beam, a photo detector detects intensity of the output laser beam to produce a photo detection signal which corresponds to the intensity of the output laser beam and which is sent to a controller. The controller controls the semiconductor laser unit in response to the photo detection signal and adjusts intensity of the excitation laser beam to keep the intensity of the output laser beam substantially constant. The solid-state laser medium may be pumped from an end surface or a side surface. An optical function element, such as a wavelength conversion element, a Q switch element, may be located outside or inside of the laser resonator.

Abstract: A method is provided for controlling the output frequency of a laser having a lasant gain medium which is characterized by at least two gain curve distributions over a range of lasant frequencies and having a laser cavity which is characterized by at least one resonant frequency within one gain curve distribution. The method comprises the steps of: locating in the laser cavity a first Lyot filter which has a transmission band which favors the frequency range of one gain curve distribution in preference to the frequency range of the other gain curves; and locating in the cavity a second Lyot filter which has a transmission band which favors said one resonant frequency within the frequency range of the one gain curve, whereby an essentially single frequency output is obtained.

Abstract: A laser diode light source comprises at least two laser diodes (1,2). The beams (3,4) of the diodes (1,2) are combined together by, for example, a polarising beam combiner (11) and the combined beam (18) is focused by a lens (19) onto an optical cable (20). The beams (3,4) are also acted on in the long direction of the laser stripes of the diodes (1,2) by anamorphic beam shaping means (7,8;9,10) to reduce the length of the image formed at the end of fibre (20) by a predetermined factor, chosen such that the numerical aperture of the focused beam (18) in said long direction does not substantially exceed that of the optical fibre (20).

Abstract: A semiconductor-laser-pumped, solid-state laser includes a semiconductor pumping laser emitting pumping light, a solid-state laser medium arranged to be excited by the pumping light, and a laser resonator structure for emitting laser light from the solid-state laser medium. The solid-state laser medium is plate shaped having a thickness less than the broadening width of he pumping light in the solid-state laser medium. The semiconductor laser is arranged close to the face of the solid-state laser medium, and the laser resonator structure has an optical axis thereof coinciding with that of the pumping light.

Abstract: A laser having a Cr.sup.3+ doped Colquiriite mineral host gain element, such as Cr:LiCAF, Cr:LiSAF or Cr:LiSGAF, is pumped by the pumping beam from at least one visible laser diode to provide tunable laser emission. TheSTATEMENT OF GOVERNMENT INTERESTThe invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Abstract: An upconversion system and method for producing red, green and/or blue emissions in response to an infrared pump is operable at room temperatures. Implemented either as a laser or as phosphors, the host medium has a hexagonal CsNiCl.sub.3 -type crystal structure, a phonon wave number less than 200 cm.sup.31 1, and a rare earth dopant occupying paired lattice vacancies. The host medium has the formulation AMX.sub.3, where A is a monovalent metal, M is a divalent metal and X is a halogen; the system has been demonstrated with CsCdBr.sub.3 :Er. Green, blue and red emissions are stimulated with infrared pumps of about 800 nm, 980 nm and simultaneous 800/980 nm, respectively.

Abstract: Methods and appartus for upconverting laser sources and amplifiers that use solid state components throughout and achieve such operation with a continuous or quasi-continuous single band infrared pumping source using successive energy transfers between the pumping radiation and activator in the host of the lasant upconversion material under ordinary operating conditions.

Abstract: A signal light is coupled by a light coupler/splitter (31) with a 0.98 micron first pumping light (.lambda..sub.1) generated by a first pumping light source (21), and the coupled light is launched into an Er-doped optical fiber (1). The signal light is optically amplified in the Er-doped optical fiber. A 1.48 micron second pumping light (.lambda..sub.2) generated by second pumping light source (22) is launched into the Er-doped optical fiber (1) with a light coupler/splitter (32). This 1.48 micron pumping light contributes boost the amplified signal.

Abstract: A solid-state laser device which employs a bi-cylindrical lens as a focusing lens for focusing excitation light emitted from a semiconductor laser to pump a laser medium. Further, the radius of curvature of each cylindrical surface of the bi-cylindrical lens is selected such that a region of the laser medium to be pumped by a horizontal component of the pumping light and another region of the laser medium to be pumped by a vertical component of the pumping light are contained in a predetermined region of the laser medium. Thereby, output laser light which excels in transverse mode characteristics can be efficiently obtained without increasing the number of surfaces of lenses composing the focusing lens system. Moreover, there is provided a solid-state laser device which can be relatively small-sized and easily regulated.

Abstract: A highly-efficient solid-state blue laser that exploits a strong emission line provided by a solid-state laser medium of neodymium-doped scandium oxide (Nd:Sc.sub.2 O.sub.3) to produce a beam of coherent blue light at a wavelength matching the absorption line of cesium at 455.6 nm (0.4556 microns). The solid-state blue laser includes the laser medium of neodymium-doped scandium oxide, a semiconductor diode laser array for optically pumping the laser medium to produce a beam of coherent infrared radiation at a wavelength of approximately 1367 nm (1.367 microns), and optical means for tripling the frequency of the beam of coherent infrared radiation to produce a beam of coherent blue light at the wavelength of approximately 455.6 nm. The solid-state blue laser is simple, highly efficient and provides relatively high power outputs.

Abstract: An optically pumped single mode laser, e.g. Nd:YAG crystal (20) with planoconcave mirrors is increased in efficiency by an order of magnitude to about 8% by optics (25, 27) for focusing the high power multimode output of laser diode arrays (21, 22) into the mode volume (20') of the laser medium (20). A plurality of these optically pumped single mode lasers (1-4) may be cascaded in a ring with dichroci mirrors (M.sub.1 -M.sub.4) at the corners for coupling in the laser diode arrays, each having its own means for spatially tailoring its beam to concentrate pump distribution inside the lasing mode volume of the medium. An InGaAlAs pump diode (30) with its wavelength of the same as a lasing medium makes the ring unidirectional.The questions raised in reexamination request No. 90/002,473, filed Oct. 10, 1991, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1,570(e).