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: A solid-state laser having a laser resonator which includes an etalon to allow a single longitudinal mode of oscillation to occur in the width of the wavelength which permits the oscillation of the medium of the solid-state laser. The etalon is interposed in the resonator which is constituted of a surface of a resonant mirror and one end surface of a solid-state laser medium, and wherein the interval of the longitudinal modes of the etalon is set to be in the range from approximately one half to one width of the oscillation wavelength of the medium of a solid-state laser. At the same time, the ratio, with respect to the optical length, of the etalon to the resonator is selected to be about a half integer.

Abstract: A quantum dot laser includes a laser host material; a plurality of quantum dots disposed in the host material; and a pumping source for exciting and inducing a population inversion in the quantum dots.

Abstract: This invention describes novel 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes containing heteroaryl substituents conjugated to the fluorophore and methods for their synthesis. The heteroaryl substituted compounds (heteroaryl dyes) generally have the structure: ##STR1## wherein any or all of the substituents R.sub.1 -R.sub.7, but at least one of such substituents, is a heteroaryl group, including 5- or 6-member rings, singly or fused, containing one or more heteroatoms. The new dyes that have spectral properties that are significantly shifted from those of the parent alkyl-substituted dyes, usually accompanied by an increase in photostability and in some cases by an increase in the extinction coefficient relative to the alkyl-substituted dyes. The general method of synthesis includes formation of pyrromethene salt intermediates followed by cyclization with boron trifluoride in the presence of a base to give heteroaryl-substituted dipyrrometheneboron difluoride dyes.

Abstract: A composite slab laser medium provided with a non-doped layer containing substantially no laser active materials and a first and second doped layers provided at both sides of the non-doped layer, respectively, in such a manner to hold the non-doped layer, each of which contains a laser active material. In this composite slab laser, a first surface of the first doped layer and a second surface of the second doped layer are in contact with the outside of the composite slab laser medium and are parallel with each other. Further, a laser oscillation or an optical amplification is performed by extracting a laser beam which travels in a zig-zag path undergoing total internal reflection at the first and second surfaces employed as alternate reflecting surfaces within the composite slab laser medium. Moreover, layers made of laser glass containing Nd.sub.2 O.sub.3 of from 3 to 9% by weight is employed as the doped layers. Furthermore, a total of the thicknesses of the first and second doped layers is of from 0.

Abstract: A solid-state laser and method of operating the laser is described having a microwave driven (MWD) visible excimer fluorescence source for exciting a solid-state laser. The laser of this invention provides an efficient, compact, and tunable solid-state laser preferably for use with tunable vibronic laser crystals.

Abstract: According to the present invention there are provided a solid-state laser device using a laser rod not smaller than 180 mm in length as a laser medium, thereby capable of providing a high output power, facilitating maintenance and inspection, and permitting the reduction of size and simplification in comparison with a conventional laser device using plural laser rods, as well as a machining apparatus using the said laser device as a machining energy source, and a solid-state laser device wherein a laser medium is held in a free state within a resonator so that a longitudinal direction of the laser medium is coincident with an optical axis direction of laser beam and so that the laser medium is capable of expansion or contraction in the said optical axis direction, thereby preventing the breakage of the laser medium and the deviation of the optical axis of laser beam.

Abstract: Laser emissions are stabilized at a plurality of frequencies by passage tugh an absorbing medium pumped by light, merged therewith, to an excited energy state corresponding to pumping light frequencies. Error signals are generated in response to detection of intensity of radiation exiting the absorbing medium which deviates from that of the laser emissions at the stabilizing frequencies to correctively adjust resonant cavity length of the laser generator being frequency stabilized.

Abstract: A laser that is capable of producing light from a chosen group of frequencies not adequate or available using a single gas laser is provided. The laser is capable of producing selected and well defined light wavelengths. The laser is also capable of eliminating unwanted frequencies in order to prevent such frequencies from competing with (robbing power from) the desired wavelengths. The laser constitutes a multiple gas laser. A combination of argon and krypton is used. Argon is known to produce a good blue laser beam in the area of 488 nm. Mixed with the argon is krypton. Krypton also produces a blue output at 482 nm and 476 nm. In addition, krypton produces strong outputs in red, yellow, and green wavelengths (647 nm, 568 nm, and 529 nm respectively). Accordingly, access to each of these colors is provided by the argon-krypton in the mixture. Certain light frequencies are unnecessary and undesirable. Elimination of undesirable wavelengths is accomplished primarily through the optics used.

Abstract: A pulse forming and delivery system 10 is disclosed for forming and deliverying a pulse of electrical energy to a flashlamp 38. System 10 includes a capacitor 14 which is adapted to selectively store electrical energy from a power supply 16 and to transfer this electrical energy to flashlamp 38 when the gate portion of thyristor 12 is open. This gate portion is opened by controller 28. The total amount of light energy emanating from the laser and/or provided to flashlamp 38 is monitored by detector 42 and communicated to controller 22 by means of bus 44. When this total amount has exceeded a desired energy level, controller 22 prevents further electrical energy to be impressed upon switch controller 28 thereby, closing the gate portion of thyristor 12 and preventing any further transfer of energy to flashlamp 38.

Abstract: A system is described for automatically maintaining the group velocity dispersion (GVD) of a Gires-Tournois interferometer (GTI) as the wavelength of incident light is varied. In the system, the transmission through the GTI is monitored by a photodiode as the wavelength is varied. The transmission through the GTI provides a measure of its GVD. Thus, the output of the photodiode can be used as a control signal for adjusting the GTI in a manner to maintain its GVD at the desired level. The subject system is illustrated in conjunction with a pulsed, tunable, Ti:sapphire laser which is passively mode locked with the optical Kerr effect. The system allows the wavelength of the laser to be tuned over the bandwidth of the gain medium while maintaining a selected level of GVD from the GTI which in turn maintains the desired duration of the pulses. In addition, the GTI is used to compensate for the dispersion effects created by broad band optics in the resonator.

Abstract: A laser cavity is formed from two mirrors and an erbium fiber gain medium. One mirror is a dichroic mirror and the other is formed by a grating. The grating period determines the wavelength of light that is reflected, and can be changed by physically stretching or constricting the substrate to which the grating is attached. In one embodiment, the laser is tuned by adjusting the dimensions of the grating using a heating element. In another embodiment, the dimensions of the grating are adjusted using a piezoelectric ceramic material to which the grating is mounted.

Abstract: The invention provides a laser medium having improved photodynamical properties. The medium includes the condensed phase, namely solid or liquid phase, of a mixture of one or more rare gases and a halogen donor. The gases are first combined and then condensed to form the laser medium. A solid state rare gas crystal laser is also provided.

Abstract: Post-growth gas-impregnation of an ionic crystal is provided to achieve a high level of caged neutral diatomic species or charged diatomic species, where all other internal degrees of freedom of the species, except the vibrational, are frozen. In the former case, the neutral diatomic species (molecules) enter interstitially, while in the latter case, the charged diatomic species (anions) substitute for anions on the crystal lattice. Such a system provides an efficient mid-infrared, solid-state laser that can be pumped by a laser diode. Other uses include magnetic (Faraday) rotators, electro-optic switches, and Q-switches. The impregnation process introduces the species into the host lattice at a temperature below the melting point of the host crystal, and preferably at a phase transition of the crystal, followed by slow cooling.

Abstract: A resonantly photo-pumped x-ray laser (10) is formed of a vanadium (12) and titanium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state neon-like titanium ions (34) are resonantly photo-pumped by line emission from fluorine-like vanadium ions (32).

Abstract: Disclosed is an x-ray laser system comprising a laser containing generating means for emitting short wave length radiation, and means external to said laser for energizing said generating means, wherein when the laser is in an operative mode emitting radiation, the radiation has a transverse coherence length to width ratio of from about 0.05 to 1. Also disclosed is a method of adjusting the parameters of the laser to achieve the desired coherence length to laser width ratio.

Abstract: A low threshold resonator for an alexandrite laser receives a 680 nm pumping beam from at least one laser pump to provide alexandrite laser emission at around 751 nm. An alexandrite crystal or rod receives the 680 nm beam and has an exterior face provided with a dichroic coating highly transmissive to the 680 nm beam and highly reflective to the 751 nm emission and has an interior face provided with an AR coating antireflective to the 751 nm emission. A mirror, provided with a HR coating that is highly reflective to the 751 nm emission, has an appropriate radius of curvature and is appropriately spaced from the exterior face of the alexandrite rod to focus reflected 751 nm emission in a resonator mode on the exterior face of the alexandrite rod to assure low threshold pumping thereof. The mirror has a radius of curvature which is the same as the spacing between the exterior face of the alexandrite rod and the mirror to focus the reflected emission in the resonator mode in a spot size on the exterior face.

Abstract: A room temperature solid state laser for producing a laser emission at a wavelength of substantially 2.09 microns is disclosed. In a preferred embodiment, the laser includes: a laser cavity defined by first and second reflective elements opposing each other on a common axis to form a path therebetween; a laser crystal disposed in the laser cavity, the laser crystal having a host material capable of accepting Cr.sup.3+ sensitizer ions, Tm.sup.3+ sensitizer ions and Ho.sup.3+ activator ions; an amount of Cr.sup.3+ sensitizer ions between about 0.3% and about 2% dispersed within the host material; an amount of Tm.sup.3+ sensitzer ions between about 3% and about 12% dispersed within the host material; and an amount of Ho.sup.3+ activator ions between about 0.1% and about 0.7% dispersed within the host material; and flashlamp and means for exciting the laser crystal to produce a laser emission at substantially 2.09 microns with a slope efficiency of at least 4%, and preferably of at least 5%.

Abstract: A laser medium for use in a composite slab type laser, wherein laser active layers are divided in the longitudinal direction of the laser medium by removing at least a part of a region, which is deviated from a zigzag path and a laser beam to be extracted therefrom does not pass through. Thereby amplified spontaneous emission can be weaken and parasitic oscillation can be effectively suppressed, and further laser oscillation and light amplification can be performed for a long period of time.

Abstract: A laser medium for use in a slab laser having a light absorbing member provided in a region, wich is deviated from a zigzag path to be followed by a laser beam to be extracted therefrom and thus the laser beam does not pass through. Thereby, parasitic oscillation can be effectively suppressed, and laser oscillation and light amplification can be performed for a long period of time.

Abstract: A method of converting the laser radiation of a pump laser into another wavelength range by stimulated Raman scattering in which the laser radiation of the pump laser is conducted through a Raman medium, thus generating Stokes radiation in the other wavelength range, and an arrangement for implementing the method. The laser radiation from the pump laser leaving the Raman medium and the generating Stokes radiation are fed together to an amplifier for the laser radiation of the pump laser, and the thus amplified laser radiation of the pump laser is conducted together with the accompanying Stokes radiation through a further Raman medium for conversion of the amplified laser radiation of the pump laser into Stokes radiation.

Abstract: A miniature solid state laser is optically pumped by ultraviolet radiation produced by a surface or corona discharge. The device is monolithic in that both the optical pump and the active medium are contiguous to a base material which is optically transparent in the ultraviolet range. The disclosed device consists of a substrate, a thin metal halide or crystalline or amorphous film deposited on the bottom of the substrate and a pair of spaced electrodes on the top of the substrate. When a high voltage pulse is applied across the spaced electrodes, discharge occurs between the electrodes and produces strong ultraviolet emissions which propagate through the substrate and dissociates the metal halide molecules in the film. This causes laser emission to occur on an atomic transition of the metal atom. The active laser medium may also be a crystalline platelet or amorphous thin film containing an impurity atom or molecule (an example would be YAG doped with Nd or LiYF.sub.4 (YLF) doped with cerium).

Abstract: A laser oscillator at 535 nm produced by a chemical process yielding stimulated emission of visible radiation via fast near resonant intermolecular energy transfer comprising the steps of reacting a reaction with a first metal vapor to form metastable states of metal oxides or metal halides, transferring the energy from the metastable states to receptor metal atoms by means of near resonant energy transfer to form electronically excited receptor metal atoms in an inverted configuration, and, through multiple reflection, allowing for the repeated passage of light through the inverted gain medium so as to produce oscillation.

Abstract: An electroluminescence apparatus in which voltage is applied to a lamination of a fluorescent material layer and a dielectric layer through a pair of electrodes one of which is light-transmissible to extract fluorescence. A reflecting mirror layer is provided on the lamination while a particular relationship is established between the refractive index and the thickness of the lamination, thereby improving the efficiency with which the fluorescence is extracted.

Abstract: A laser-medium in the form of a dielectric crystal or glass doped with tetravalent chromium. The dielectric crystals are of olivine-like structure such as germanates of formula (A) (RE)GeO.sub.4 where (A=Na or Li, RE=Y, Lu or Gd), crystals of willemite structure Zn.sub.2 (Si or Ge)O.sub.4 tetrahedral sites, or any other single-crystal or polycrystalline compound containing the (Si.Ge)O.sub.4 tetrahedra in its crystal lattice, such as Ca.sub.3 La.sub.2 (SiO.sub.4).sub.6 and crystals such as YAG (Y.sub.3 Al.sub.5 O.sub.12).

Abstract: A resonantly photo-pumped X-ray laser (10) that enhances the gain of seve laser lines that also lase because of collisional excitations and recombination processes, is described.The laser comprises an aluminum (12) and erbium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like erbium ions (34) are resonantly photo-pumped by line emission from hydrogen-like aluminum ions (32).

Abstract: A room-temperature, laser-pumped, Q-switched, thulium-doped, solid state laser for producing pulses of laser emission at substantially 2 microns is disclosed. In a preferred embodiment, the laser comprises: a laser cavity defined by first and second reflective elements opposing each other on a common axis to form a reflective path therebetween; a laser crystal disposed in the laser cavity, the laser crystal having a host material doped with an amount of thulium activator ions sufficient to produce a laser emission at substantially 2 microns from the .sup.3 F.sub.4 to .sup.3 H.sub.

Abstract: An erbium-doped fiber laser amplifier (1), characterized by the fact that said fiber (3) is doped to a concentration lying in the range 5 ppm to 50 ppm, that the length of said fiber lies in the range 250 m to 30 m depending on the selected concentration of doping, and that the radial position of the doped zone substantially coincides with the energy maximum of the set of propagation modes in said fiber at the pumping wavelength.

Abstract: A chemical process yielding stimulated emission of visible radiation via fast rear resonant intermolecular energy transfer comprising the steps of reacting a first metal or semimetal vapor with a reactant to produce a metastable excited state reaction product and transferring energy stored in the metastable excited state of the reaction product to a second metal or semimetal vapor by means of near resonant energy transfer to form electronically excited receptor atoms in a population inversion relative to a lower level of excitation of the receptor atoms. In the preferred form of the process, the first metal or semimetal vapor is a group IIIA or IVA element. The second metal or semimetal vapor is of a group IIA or IVA element and the reactant is either ozone, nitrogen oxide, nitrogen dioxide or a halide.

Abstract: A method andan apparatus for producing a photopumped VUV laser in an Mo.sup.6+ ion-containing plasma comprise photopumping the Mo.sup.6+ ion-containing plasma with radiation from Mo.sup.11+ ions. In one embodiment, the Mo.sup.6+ ion-containing plasma has an electron density of less than about 10.sup.18 cm.sup.-3 and the Mo.sup.11+ ions are contained in a plasma having an electron density greater than about 10.sup.20 cm.sup.-3.

Abstract: The present invention relates to an analog frequency modulatable laser. The radiation of the lasing medium is analog frequency modulated by change of the optical path length by movement of reflective mirrors forming the resonant cavity at the frequency of radiation of the laser in a manner corresponding to an information signal. In one embodiment, a magnetostrictive material is deposited on and bonded to the outer periphery of an active lasing medium having appropriate mirrors on the ends thereof. The magnetostrictive material is exposed to an information encoded magnetic field and physically expands or contracts the physical length of the lasing medium along the optical axis of the lasing medium corresponding to the modulated information of the magnetic field.

Abstract: Apparatus for providing self-organized, phase-matched harmonic generated radiation which includes a single-mode fiber doped with ytterbium or ytterbium-aluminum which is placed in a laser cavity having a mode-locking and a Q-switching apparatus.

Abstract: A substantially rectangular slab of laser material has a pair of opposing concave edge faces to reduce parasitic oscillations. The concavities can be curved in either the transverse or longitudinal directions or both, i.e., they are toroidal sections. The slab can be Nd:YAG. Brewster ends and chamfered corners can be provided for the slab as well as tapered portions for the concavities. In a laser, the concave portions have a length slightly greater than that of the pump lamps. A pair of siderails are over the concave portions to reduce optical distortion.

Abstract: A laser gain medium has a diamond coating in order to strengthen it and reduce parasitic oscillations. The medium can be a slab with chamfered corners with the coating on the edge faces and the corners, or a rod with the coating going all the way around it to eliminate stress corrosion and provide a compressive stress. The medium can be Nd:YAG and the coating can have a parasitic absorbing dopant. In a laser, the length of the coating preferably is the same as the length of the medium. For the slab, siderails can be used with a length slightly shorter than that of the coating.

Abstract: A fiber laser differential sensor measures changes in a selected parameter by means of several single fiber laser sensors which are sensitive to both changes in the selected parameter and changes in other parameters which are not of interest. Each single sensor is comprised of two fiber lasers which are each optically coupled to a third fiber so that energy is exchanged between each of the laser fibers and the third fiber. The single sensor structure is arranged so that it operates with least loss when the two lasers oscillate at a common frequency. The common frequency is, in turn, sensitive to changes in the optical path length of either of the fiber lasers. The single sensors are arranged so that their optical path lengths change in response to changes in the selected and other parameters. The outputs of the sensors are beat together to eliminate variations due to parameters other than the desired parameter.

Abstract: An intercalation compound obtained by intercalating a halide of sodium or an element belonging to the group IV of the periodic table such as NaBr, SiCl.sub.4, etc., in a layer crystal substance such as graphite is suitable as an optical resonator in a device for emitting coherent radiation together with an exciting energy supplying means which can radiate synchroton radiation or plasma focus X-rays, particularly in an X-ray laser for emitting X-rays having a wavelength of 10 .ANG. or less.

Abstract: The method of producing a coherent boson beam causing a coherent light to be incident on dense matter.

Abstract: A neodymium or other rare earth doped solid state laser is pumped by a matched high efficiency laser diode, including a diode array and a multi-spatial mode extended emitter diode, resulting in a compact, high efficiency and long lifetime laser assembly. The cavity mode volume is matched to a region of absorption in the pumping volume formed by the focused diode beam. Output is in the near infrared range, but can be converted to the visible spectrum by an intra-cavity frequency doubler. A doubling crystal, e.g., KTP, is placed in an optimum location in the laser cavity. Polarization of the beam for frequency doubling may be achieved by using a birefringent material for the rod or by stressing a non-birefringent rod. An amplitude noise suppression etalon may also be placed at an optimum position in the laser cavity. A folded cavity configuration produces a pair of beam waists in the cavity. Pulsed operation can be produced by means of a Q-switch.

Abstract: In a transverse-pumped, solid-state laser, a nonabsorptive cladding surrounds a gain medium. A single transverse mode, namely the TEM.sub.00 mode, is provided. The TEM.sub.00 mode has a cross-sectional diameter greater than a transverse dimension of the gain medium but less than a transverse dimension of the cladding. The required size of the gain medium is minimized while a threshold for laser output is lowered.

Abstract: A broadly wavelength-tunable laser is provided which comprises as the laser medium a single crystal of MBO.sub.3 :Cr.sup.3+, where M is selected from the group of Sc, In and Lu. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.

Abstract: An operational X-ray laser (30) is provided that amplifies 3p-3s transition X-ray radiation along an approximately linear path. The X-ray laser (30) is driven by a high power optical laser. The driving line focused optical laser beam (32) illuminates a free-standing thin foil (34) that may be associated with a substrate (36) for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the X-ray laser gain medium. The X-ray laser (30) may be driven by more than one optical laser beam (32, 44). The X-ray laser (30) has been successfully demonstrated to function in a series of experimental tests.

Abstract: Chromium doped colquiriite, LiCaAlF.sub.6 :Cr.sup.3+, is useful as a tunable laser crystal that has a high intrinsic slope efficiency, comparable to or exceeding that of alexandrite, the current leading performer of vibronic sideband Cr.sup.3+ lasers. The laser output is tunable from at least 720 nm to 840 nm with a measured slop efficiency of about 60% in a Kr laser pumped laser configuration. The intrinsic slope efficiency (in the limit of large output coupling) may approach the quantum defect limited value of 83%. The high slope efficiency implies that excited state absorption (ESA) is negligible. The potential for efficiency and the tuning range of this material satisfy the requirements for a pump laser for a high density storage medium incorporating Nd.sup.3+ or Tm.sup.3+ for use in a multimegajoule single shot fusion research facility.

Abstract: A source of coherent blue light comprises a diode laser for pumping a Nd.sup.3+ doped member of lasant material disposed within an optical resonator for exciting the .sup.4 F.sub.3/2 -.sup.4 I.sub.9/2 laser transition of a wavelength within the range of 0.870 to 0.960 .mu.m. The laser radiation within the optical resonator is doubled by means of a doubler crystal of a non-linear, electro-optic material to produce blue light which is then extracted from the optical resonator as an output beam. A thermo-electric cooler is coupled in heat-exchanging relation with the Nd.sup.3+ doped laser material to improve the efficiency and the doubler crystal is temperature controlled for phase matching to the laser radiation within the range of 0.870 to 0.960 .mu.m. The diode pump laser is preferably either a GaAlAs or GaAs diode laser producing pumping radiation of a wavelength of approximately 0.810 .mu.m.

Abstract: There are provided chemical lasers which provide pulsed radiation in the visible or near visible (denoted hereafter as short-wavelength) range. The novel pulsed short-wavelength chemical lasers are operated by detonating an explosive mixture which contains fuel and lasants, the detonation resulting in electronically excited molecules. Lasing can be brought about by energy transfer within such molecules, or by energy transfer from such excited molecules to other molecules or to atoms resulting in the desired short-wavelength laser emission. The lasers can be operated at high pulse energies.

Abstract: A number of ordered colloidal suspension Bragg reflection optical devices are disclosed each of which comprises a receiver for receiving incident electromagnetic radiation, a modulator, responsive to at least one characteristic of the received radiation, for modulating the received radiation and an emitter for emitting the modulated radiation. The receiver, modulator and the emitter comprise a crystalline colloidal suspension having a lattice structure comprised of a plurality of parallel planes of ordered, electrically charged spheres suspended in an optically active medium, adjacent ones of the planes having a substantially uniform spacing therebetween. The optically active medium comprises molecules selected to have a predetermined index of refraction, radiation absorption, radiation emission or a nonlinear optical response property at a wavelength substantially equal to twice the spacing between the planes.

Abstract: The congruently melting composition of gadolinium scandium gallium garnet comprisesGd.sub.2.96.+-.0.03 Sc.sub.1.90.+-.0.05 Ga.sub.3.14+0.05 O.sub.12.The composition may be used as the substrate for magnetic bubble domain devices or, when doped with a suitable activator (e.g., Cr.sup.+3 or Nd.sup.+3 or both), may serve as the active medium of a solid state laser.

Abstract: A solid state laser in which molecules containing transition metal ions form the lasing medium. More particularly, the electronic states of molecular complexes containing transition metal ions, which are in closed shell configurations, are pumped by an ultraviolet source to emit coherent radiation.

Abstract: A laser system which includes a solid state fluorescent converter having fluorescent converter particles distributed in a glass support. The fluorescent particles are selectively distributed in the glass matrix permitting concentration of the fluorescent particles in the vicinity of laser.

Abstract: An opto-electronic device has an atomic layer superlattice semiconductor comprising different semiconductor materials periodically piled up, each material having an atomic layer thickness. The superlattice semiconductor has a bandgap different from an alloy semiconductor having equivalently the same composition as the former. In a semiconductor laser, as clad layers, the atomic layer superlattice semiconductor having equivalently the same composition as a Zn.sub.0.42 Cd.sub.0.58 S alloy semiconductor and a larger bandgap than the later is used, and a ZnSe.sub.0.94 S.sub.0.06 alloy semiconductor as an active layer is located between the cladding layers. The double-hetero structure semiconductor laser thus provided can perform the lasing at 470 nm at room temperature.

Abstract: A laser has been made using a Nd.sup.3+ -doped fluoro-zirconate heavy metal fluoride (HMF) glass multimode fiber which lases in a range equal to or greater than 1.32 micrometers. The fiber laser was made for forming a glass fiber from a core glass composition comprising 52.8 mole % ZrF.sub.4, 19.9 mole % BaF.sub.2, 2.5 mole % LaF.sub.3, 3.0 mole % AlF.sub.3, 19.9 mole % NaF, 0.4 mole % InF.sub.3, and 1.5 mole % NdF.sub.3 the active dopant and the composition of the cladding glass comprises 39.6 mole % ZrF.sub.4, 17.9 mole % BaF.sub.2, 4.0 mole % LaF.sub.3, 3.0 mole % AlF.sub.3, 21.9 mole % NaF, 0.4 mole % InF.sub.3, and 13.2 mole % HfF.sub.4.