Abstract: A monolithic diode pumped solid-state laser (11) comprising as the laser host neodymium-doped yttrium orthovanadate (Nd:YVO.sub.4) (12, 52) or neodymium-doped gadolinium orthovanadate (Nd:GdVO.sub.4) (57, 67) operating on the .sup.4 F.sub.3/2 .fwdarw..sup.4 I.sub.9/2 (.about.914 nm or .about.912 nm respectively) transition, to which a suitable nonlinear optic material (16), such as potassium niobate (KNbO.sub.3) or beta barium borate (BBO), is bonded. The nonlinear crystal gives rise to intracavity frequency doubling to .about.457 or .about.456 nm. The microlaser is a composite cavity formed from a gain medium crystal and a nonlinear frequency doubling material which together have four spaced parallel dielectrically coated faces (14, 17, 18, 15) and which is positioned in close proximity to a diode laser pump source (13) for phase-matched harmonic generation of blue light along an axis of propagation which lies substantially perpendicular to the two faces of the composite cavity.

Abstract: The ellipticity of a thermal lens is controlled in a diode-pumped anisotropic crystal, such as Nd:YVO4. The crystal has two opposing optical end faces through which a pump beam and an output beam pass. The crystal also has opposing "c" axis crystal faces normal to a "c" axis of the crystal, and opposing "a" axis crystal faces that are normal to an "a" axis of the crystal. A mount supports the crystal and serves as a heat sink. A path is created to conduct heat from the crystal through the "c" faces, while the "a" faces are thermally isolated from heat conduction. The thermal lens ellipticity is controlled in order to produce a round, diffraction limited gaussian beam suitable for applications that require a high power, good quality beam from a simple, reliable laser source.

Abstract: A solid state laser apparatus and a laser machining apparatus are provided to provide high power laser beam having an excellent condensing performance at high efficiency and with high reliability. In the solid state laser apparatus, a recess is provided in a supporter disposed on a slab side surface at an excitation area corresponding portion. A high reflectance body having a cooling water filtrating groove is disposed in the recess to contact with a slab facing surface with pressure. The supporter contacts slab longitudinal both ends with pressure through a silicon rubber plate which is transparent to excitation light. A transparent silicon rubber O-ring is disposed to extend over an entire peripheral portion of a plane formed by a slab surface including the supporter pressure contacting porting and the supporter so as to seal cooling water and elastically support the slab.

Abstract: A multiform crystal 10 suitable for laser applications is described. The multiform crystal 10 comprises at least two single crystal segments 12 fused together with a joint 14 therebetween, the joint being substantially optically transparent to light propagating through the crystal 10. The multiform crystal 10 is formed by polishing two single crystal segments 12 to form at least one optically flat face on each segment. The polished faces are cleaned and contacted against one another to form a joint 14 between the crystal segments 12. Substantially all the oxygen in the joint 14 is removed. The joint 14 is maintained at a sufficiently high temperature and pressure to join the segments together at the joint forming the substantially optically transparent joint 14. Mounting fixtures suitable for holding the crystal segments 12 firmly against one another in a furnace, without causing undesirable thermal expansive forces to be exerted on the segments 12, are also described.

Abstract: A new class of solid state laser crystals and lasers are formed of transition metal doped sulfide, selenide, and telluride host crystals which have four fold coordinated substitutional sites. The host crystals include II-VI compounds. The host crystal is doped with a transition metal laser ion, e.g., chromium, cobalt or iron. In particular, Cr.sup.2+ -doped ZnS and ZnSe generate laser action near 2.3 .mu.m. Oxide, chloride, fluoride, bromide and iodide crystals with similar structures can also be used. Important aspects of these laser materials are the tetrahedral site symmetry of the host crystal, low excited state absorption losses and high luminescence efficiency, and the d.sup.4 and d.sup.6 electronic configurations of the transition metal ions. The same materials are also useful as saturable absorbers for passive Q-switching applications. The laser materials can be used as gain media in amplifiers and oscillators; these gain media can be incorporated into waveguides and semiconductor lasers.

Abstract: The present invention is a fluorozirconate laser host doped with a suffict amount of Tm.sup.3+ ions to permit significant emission at a wavelength between about 790 nm and about 830 nm when pumped at a wavelength or wavelengths to excite Tm.sup.3+ ions from the .sup.3 H.sub.6 ground state to the .sup.3 F.sub.4 excited state, and then from the .sup.3 F.sub.4 excited state to the .sup.3 H.sub.4 excited state.

Abstract: Rare-earth doped single-crystal amplifiers serve to simultaneously amplify member channels of an optical fiber WDM system. A tailored amplification bandwidth sufficient for this purpose is the result of a variety of "defects" which after the local crystal field as "seen" by dopant ions.

Abstract: Ce.sup.3+ -doped LiSrAlF.sub.6 crystals are pumped by ultraviolet light which is polarized along the c axis of the crystals to effectively energize the laser system. In one embodiment, the polarized fourth harmonic light output from a conventional Nd:YAG laser operating at 266 nm is arranged to pump Ce:LiSrAlF.sub.6 with the pump light polarized along the c axis of the crystal. The Ce:LiSrAlF.sub.6 crystal may be placed in a laser cavity for generating tunable coherent ultraviolet radiation in the range of 280-320 nm. Additionally, Ce-doped crystals possessing the LiSrAlF.sub.6 type of chemical formula, e.g. Ce-doped LiCaAlF.sub.6 and LiSrGaF.sub.6, can be used. Alternative pump sources include an ultraviolet-capable krypton or argon laser, or ultraviolet emitting flashlamps. The polarization of the pump light will impact operation.

Abstract: A solid state laser is provided having as the laser medium diamond and an optically active dopant element which is found to lase in the solid matrix. The dopant is preferably titanium, vanadium, chromium, iron, cobalt, nickel, zinc, zirconium, niobium, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and uranium. Erbium is especially preferred. The laser medium is formed as dopants are added by ion implantation to a diamond crystal as the diamond is grown by chemical vapor deposition.

Abstract: A laser waveguide medium is provided comprising:a laser glass substrate wherein the substrate is a glass comprising (on an oxide composition basis):______________________________________ Mole % ______________________________________ P.sub.2 O.sub.5 50-70 Al.sub.2 O.sub.3 4-13 Na.sub.2 O 10-35 La.sub.2 O.sub.3 0-6 Ln.sub.2 O.sub.3 >0-6 R'O 0-20 R.sub.2 O 0-18 ______________________________________wherein Ln.sub.2 O.sub.3 is the sum of the oxides of active lasing lanthanides of atomic numbers 58-71, R'O is the sum of oxides of Mg, Ca, Cr, Ba, Zn and Pb, and R.sub.2 O is the sum of oxides of Li, K, Rb and Cs; anda waveguide region embedded in the substrate, the waveguide region having a higher refractive index than the substrate and the waveguide region having an inlet region through which light can enter and an outlet region through which light can exit.

Abstract: An upconversion laser system that uses solid state components throughout and achieves such operation with a substantially coherent, continuous or quasi-continuous single band infrared pumping source using successive energy transfers between the sensitizer and activator in the host of the lasant upconversion material.

Abstract: The present invention encompasses an apparatus for pumping a vibronic laser, which comprises: a transition-metal ion-containing solid state vibronic laser gain medium; a means for exciting said laser medium to emit coherent radiation said exciting means being a pumping source comprising at least one laser diode operating at a wavelength shorter than 750 nm; and an optical resonator means for generating and controlling said coherent radiation. The present invention also encompasses a method of pumping a vibronic laser comprising the steps of: generating a laser diode pumping beam at a wavelength shorter than 750 nm; exciting a transition-metal ion-containing solid state vibronic laser gain medium by impinging said laser diode pumping beam on said transition-metal ion-containing solid state laser gain medium, so as to excite the laser medium; and an optical resonator to emit coherent radiation.

Abstract: An ultraviolet solid state laser includes: (a) a laser cavity defined by a et of opposing mirrors, (b) a laser medium disposed in this laser cavity, where this medium includes a LiSrAIF.sub.6 (LiSAF) host material doped with enough cerium ions to produce a longitudinal mode laser emission when this laser medium is pumped; and (c) a source of pumping radiation.

Abstract: Optical microcavities are potentially useful as light emitters for, e.g., flat panel displays. Such microcavities comprise a layer structure, including two spaced apart reflectors that define the cavity, with a layer of organic (electroluminescent) material disposed between the reflectors. We have discovered that a microcavity can simultaneously emit radiation of two or more predetermined colors such that the emission has a desired apparent color, exemplarily white. Emission of two or more colors requires that the effective optical length of the cavity is selected such that the cavity is a multimode cavity, with the wavelengths of two or more of the standing wave modes that are supported by the cavity lying within the emission region of the electroluminescence spectrum of the active material.

Abstract: A master oscillator and power amplifier configuration for a high power cladding-pumped laser structure, and a method of making same, is disclosed. The laser structure comprises a single mode core having at least one oscillator defined therein, and a first and second cladding layer for waveguiding and radiation retention. The core is doped with refractive-index modifying dopants, in addition to ionized rare earth elements. The refractive-index modifying dopants facilitate writing one or more spaced pairs of index gratings in the core, each pair defining an oscillator. Oscillator cavity length is determined by the desired mode spacing and is less than one-half of the single mode core length. The index gratings are formed via a ultraviolet light-induced refractive index change in the core, which index change varies periodically along the core. The periodic variation is created by projecting an interference pattern on the core.

Abstract: A thulium-doped solid state laser is provided capable of operation at a wlength having a shallow absorption depth in tissue. The laser is comprised of a laser cavity defined by first and second reflecting surfaces opposing each other on an optical axis, a thulium-doped YALO crystal disposed in the cavity, and a pump source for pumping the crystal with a pump beam at a preselected wavelength to enable the crystal to emit a most preferred 1.94 micron laser output. The thulium-doped YALO crystal is preferably an a-cut crystal. Such alignment of this material provides a reliable mode at 1.94 microns which has excellent tissue absorption characteristics for medical applications. The length l of the crystal, the concentration N of the dopant and the transmissivity T of the output coupler, which define an expression Nl/T, can be varied as long as the expression Nl/T produces a value which does not exceed about 0.32 centimeters.

Abstract: A diode pumped, multiaxial mode, intracavity frequency doubled laser resonator has high amplitude stability, meaning that the percent root mean square noise (% RMS) of the doubled output beam power is low. A diode pump source supplies a pump beam to a laser crystal positioned in a resonator cavity and produces a multiaxial mode infrared beam that is incident on a doubling crystal, also positioned in the resonator. A frequency doubled output beam is produced that has an RMS of less than 3%. The laser is highly efficient, provides high output power and its output beam is of high spatial quality.

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: An optical gain medium comprises a multi-phase system wherein: a first phase is an electromagnetic radiation emitting and amplifying phase (16) that is comprised of doped semiconductor nanocrystals; a second phase is an electromagnetic radiation scattering phase (14); and a third phase is a substantially transparent (at the wavelengths of interest) matrix phase (12). The emission phase may consist of ZnS nanoparticles that are doped with Mn.sup.2+, the scattering phase may comprise TiO.sub.2 or Al.sub.2 O.sub.3 nanoparticles, and the matrix phase may comprise a glass or polymer body, layer or coating. At least one dimension of a body, layer, or coating comprised of the gain medium may be less than a scattering length associated with the scattering phase.

Abstract: A mode-locked solid state laser is disclosed for generating ultrashort optical pulses from solid state material. The laser can comprise a solid state gain medium, at least one mirror connected to the medium and a semiconductor multiple quantum well saturable (MQW) absorber in contact with the mirror, for mode-locking the solid state gain medium. The solid state medium can be composed of but is not limited to Titanium Sapphire, Cr:YAG, Cr:Fosterite, Nd:YAG, Nd:glass, color center lasers, semiconductor diode lasers, optically active fiber lasers, and the like. The absorber can include a structure consisting of 70 Angstrom wells of GaAs and 100 Angstrom barriers of AlGaAs. The generated optical pulses can be used in a wide variety of applications such as diagnostic testing, communications, computers, medicine, automotive applications and the like.

Abstract: A system for producing an optical gain, the system including a host having a light conducting path doped with thulium, holmium, and at least one rare earth selected from the group consisting of europium and terbium in respective amounts sufficient to produce an optical gain by energizing the thulium to a .sup.3 H.sub.4 state to produce an optical gain by a .sup.3 H.sub.4 -.sup.3 F.sub.4 transition, producing a 1.47 .mu.m wavelength output. There is subsequent energy transfer from the .sup.3 F.sub.4 state of the thulium to a .sup.5 I.sub.7 state of the holmium, and energy transfer from the .sup.5 I.sub.7 state to the rare earth selected from the group consisting of europium and terbium. The system can include oscillator, amplifier, and superluminescence source configurations. A method for making and a method for using the system are included.

Abstract: A solid state laser includes a diamond crystal as a medium of laser beam emission, which generates a laser beam having a wavelength of 225 to 300 nm through exciton light emission.

Abstract: An intracavity frequency-doubled solid-state laser uses a Nd:GdVO.sub.4 laser gain chip to generate a beam of visible laser light which may have wavelengths substantially in the green portion of the optical spectrum. A back end of the laser cavity is defined by an entrance mirror while a front end of the laser cavity is defined by a mirrored surface. A laser diode generates pump light which is transmitted through the entrance mirror into the laser gain chip. The laser gain chip, which may be immediately adjacent the entrance mirror, emits fundamental laser light having a wavelength of approximately 1063 nm in response to the pump light. A frequency doubler chip positioned immediately adjacent the laser gain chip doubles the frequency of the fundamental laser light to produce harmonic laser light having a wavelength of substantially 532 nm.

Abstract: A laser material for a solid-state laser that, when pumped by light having a wavelength in a suitable pump band, emits electromagnetic radiation having a wavelength lying in the range 2.0.ltoreq..lambda..ltoreq.2.1 .mu.m. The laser host material includes thulium-doped lutetium yttrium aluminum garnet (Tm:LuYAG) of approximate chemical composition (Tm.sub.x (Y.sub.w Lu.sub.1-w).sub.1-x).sub.3 Al.sub.5 O.sub.12, with x lying approximately in the range 0.01.ltoreq.x.ltoreq.0.5 and w lying in the range between 0.01 and 0.99. In particular, the Tm:LuYAG material produces light with wavelengths in the range .lambda.=2.020-2.024 .mu.m, where the normally-absorbing atmosphere has a transmission window with markedly reduced (or, alternatively, markedly enhanced) absorption. Another suitable group of laser materials has the chemical composition (Tm.sub.x (Y.sub.w Lu.sub.1-w-z Sen.sub.z).sub.1-x).sub.3 Al.sub.5 O.sub.12, with x lying approximately in the range 0.01.ltoreq.x.ltoreq.0.5, w lying in the range 0.01.ltoreq.

Abstract: A solid state laser which has Y.sub.x Gd.sub.1-x VO.sub.4 doped with Nd wherein 0.ltoreq..times..ltoreq.0.5 as a solid laser medium.

Abstract: Neodymium-doped gehlenite crystal and laser using said crystal. The crystal according to the invention has the formula Ca.sub.2-x Nd.sub.x Al.sub.2+x Si.sub.1-x O.sub.7 with 0<.times..ltoreq.1. This crystal can be used as a laser emitter (4) optically pumped by a laser diode (6), whose temperature is not controlled by a Peltier element component.

Abstract: A high power, highly efficient laser that produces a polarized, round diffraction limited gaussian beam is disclosed. A strong thermal lens laser crystal with controlled ellipticity, is mounted in a laserhead and pumped by a fiber-bundle-coupled diode source. The pump beam diameter in the crystal is greater than the crystal's TEMOO mode diameter. The laser operates well over a large range of pump powers. Its slope efficiency in the TEMOO mode is greater than 40%, with an overall efficiency greater than 25%. One of the lasing crystals used is Nd:YVO4. This material exhibits high gain and a short upper state lifetime. These properties make it attractive in designing a Q-switched laser, or one that is insensitive to optical feedback.

Abstract: An Er:YVO.sub.4 laser oscillator has an excitation light source constituted by a laser diode and a medium constituted by an Er:YVO.sub.4 crystal in which Er.sup.3+ ions are activators and YVO.sub.4 is a host material. The oscillation light is perpendicular or parallel to c-axis of the crystal. The laser operates in target wavelengths on energy transitions of the Er.sup.3+ ions, the target wavelengths being 510 nm to 590 nm, 840 nm to 870 nm, 970 nm to 1020 nm, and 1450 nm to 1700 nm. The crystal is coated with a TiO.sub.2 --SiO.sub.2 system high reflection mirror coating and a fluoride megnesium-zeolite system antireflection coating corresponding to the target wavelengths and a fluoride megnesium-zeolite system antireflection coating corresponding to the wavelength of the laser diode. These coatings together with an output mirror constitute a resonator. For manufacturing the crystal, Er.sub.2 O.sub.3, Y.sub.2 O.sub.3, and V.sub.2 O.sub.

Abstract: Disclosed is a source of visible and ultraviolet radiation that provides a focused beam for performing chemical analysis of a test element having a biological fluid deposited thereon.

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 light source for an interferometric fiber optic gyroscope ("IFOG") includes a thulium (Tm.sup.+++) doped optical fiber which exhibits superluminescence in a wavelength region substantially centered at about 1.8 microns.

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 laser apparatus, system and method include a laser crystal formed of thulium-doped yttrium-lithium-fluoride, and a laser diode arranged in proximity to the laser crystal. The laser diode is capable of emitting a first laser light which is suitable for use as a pump beam for causing lasing to occur in the laser crystal. In response to the first laser light from the laser diode, the laser crystal emits a second laser light at a wavelength which is relatively highly-absorbed by organic tissue and/or water. The second laser light is therefore well-suited to medical applications, for example, and can be used to irradiate organic tissue for medical treatment.

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 variable pulsewidth laser system is disclosed which employs an oscillating reflector to control the duration of laser pulses. In one embodiment, the oscillating mirror is swept (e.g., caused to swing back and forth) about an axis distinct from the optical axis, such that resonant conditions suitable for laser beam generation occur only at a particular location in the oscillating sweep path. By varying the scanning waveform, laser pulses of different durations can be generated.

Abstract: In order to improve an apparatus for removing material from a target, comprising a high-power laser generating laser pulses with a pulse duration in the picosecond range and comprising a resonator, in which a mode-locking device and a Q-switch are arranged, a frequency multiplier following the high-power laser and a beam guide for focusing the laser beam coming from the frequency multiplier onto the target, such that the energy in the single laser pulses having a pulse duration in the picosecond range is as high as possible, it is suggested that the resonator have fully reflecting end mirrors for generating single high-energy laser pulses, that a system for the controlled coupling out of single pulses be arranged in the resonator and that a control be provided for coupling out a single pulse following release of the laser activity by the Q-switch and the build up of the single pulse after repeated round trips through the resonator.

Abstract: Yb.sup.3+ and Nd.sup.3+ doped Sr.sub.5 (VO.sub.4).sub.3 F crystals serve as useful infrared laser media that exhibit low thresholds of oscillation and high slope efficiencies, and can be grown with high optical quality. These laser media possess unusually high absorption and emission cross sections, which provide the crystals with the ability to generate greater gain for a given amount of pump power. Many related crystals such as Sr.sub.5 (VO.sub.4).sub.3 F crystals doped with other rare earths, transition metals, or actinides, as well as the many structural analogs of Sr.sub.5 (VO.sub.4).sub.3 F, where the Sr.sup.2+ and F.sup.- ions are replaced by related chemical species, have similar properties.

Abstract: A solid state waveguide laser system is comprised of a cavity resonator formed of a solid state gain medium extending between input and output surfaces and having a reflectivity medium laterally bounding the gain medium and wherein the index of refraction of the reflectivity medium is greater than that of the gain medium.

Abstract: Solid state laser gain media of segmented construction are composed of at least two segments of a doped crystalline laser host which are arranged in crystallographic alignment, wherein the dopant concentration varies from segment to segment to provide gradient doping levels for reducing thermally generated stress/strain in the lasing operation.

Abstract: An eye-safe short pulse room-temperature solid state laser emitting at about 2.1 microns is optically pumped by diode lasers emitting at about 1.9 microns Absorption spectra of Ho ions in YAG (Yttrium Aluminum Garnet) and YLF (Yttrium Lithium Fluoride) host crystals are described. Optical pumping is performed by high-power diode lasers emitting at about 1.91 microns consisting of a GaInAsSb/AlGaAsSb quantum-well active region and AlGaAsSb cladding layers grown on GaSb substrates.

Abstract: A calcium yttrium silicate oxyapatite laser crystal doped with thulium provides a laser material finding particular utility in 2 .mu.m diode pumped lasers. The calcium yttrium silicate oxyapatite doped with trivalent thulium, preferably has the formulaCa(Tm.sub.x Y.sub.1-x).sub.4 (SiO.sub.4).sub.3 O, where x=0.0025-0.12.

Abstract: An upconversion laser system that uses solid state components throughout and achieves such operation with a continuous or quasi-continuous single band infrared pumping source using successive energy transfers between the sensitizer and activator in the host of the lasant upconversion material.

Abstract: A system for producing an optical gain, the system including a host having a light conducting path doped with thulium, holmium, and at least one rare earth selected from the group consisting of europium and terbium in respective amounts sufficient to produce an optical gain by energizing the thulium to a .sup.3 H.sub.4 state to produce an optical gain by a .sup.3 H.sub.4 -.sup.3 F.sub.4 transition, producing a 1.47 .mu.m wavelength output. There is subsequent energy transfer from the .sup.3 F.sub.4 state of the thulium to a .sup.5 I.sub.7 state of the holmium, and energy transfer from the .sup.5 I.sub.7 state to the rare earth selected from the group consisting of europium and terbium. The system can include oscillator, amplifier, and superluminescence source configurations. A method for making and a method for using the system are included.

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: 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: In a preferred embodiment, a Tm.sup.3+ :YAG laser crystal and a Ho.sup.3+ :YAG laser crystal are placed within a reflective path of a laser cavity for intracavity pumping the Ho.sup.3+ :YAG laser crystal. The Tm.sup.3+ :YAG laser crystal emits a substantially 2.0 .mu.m laser emission after being resonantly end-pumped by a pump beam at a wavelength of about 785 nm and the substantially 2.0 .mu.m laser emission is used to pump the Ho.sup.3+ :YAG laser crystal. The intracavity-pumped Ho.sup.3+ :YAG laser crystal emits an output laser emission at substantially 2.1 .mu.m. The slope efficiency of the Ho.sup.3+ :YAG laser crystal output power is about 40% of the pump power absorbed by the Tm.sup.3+ :YAG laser crystal.

Abstract: Solid state laser gain media of the composition Cr.sup.+3 :XYZF.sub.6 wherein X is an alkali metal ion; Y is an alkaline earth metal ion, Cd.sup.+2 or Mg.sup.+2 ; and Z is Al.sup.+3, Ga.sup.+3 or Sc.sup.+3 are provided with gradient Cr doping levels for reducing thermally generated stress/strain in the lasing operation.

Abstract: The directly pumped holmium (Ho) quasi-two level laser of the invention comprises a directly pumped holmium laser having a host material doped with an amount of holmium ions sufficient to produce an output laser emission at a wavelength of about 2.1 .mu.m when the holmium laser is pumped by a pump beam at a wavelength of about 2 .mu.m and a pumping laser for producing the pump beam. In an exemplary embodiment, the pumping laser comprises a Cr,Tm:YAG laser pumped by a flashlamp.

Abstract: An all-solid-state tunable pulse laser using a titanium-doped sapphire single crystal in which a pumping source is a pulse beam, which is produced by doubling with a KTiOPO.sub.4 under a 90.degree. phase matching condition a Q-switching laser pulse of a light beam, which is produced by a transition of .sup.4 F.sub.3/2 .fwdarw..sup.4 I.sub.11/2 in a neodymium-doped yttrium aluminum perovskite crystal pumped with a quasi-continuous diode laser.

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.