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

Abstract: The disclosure is a high-power solid laser in which an emissive array of semiconductor lasers in a first stage pumps a solid YAG-type laser in a second stage. The structure of the emissive array, which is an integrated circuit, includes rods of semiconductor lasers alternating with grooves, the rods and grooves being parallel. The invention involves incrusting the material of the solid laser bars into the grooves between the rods of semiconductor lasers. This material is either placed in hybrid form or deposited to make an integrated structure.

Abstract: This invention relates to solid state lasers and more particularly to laserable rods, slabs or other configurations where thermal effects and/or ground state absorption cause a degradation in lasing efficiency and/or beam quality. The improvement in operating efficiency is achieved by using a composite of lasing and non-lasing sections. The composite is formed using diffusion bonding techniques.

Abstract: Dynamic variation in the color produced by a silicon quantum dot laser is achieved by utilizing segmented sections or patches of quantum dots of differing sizes to produce different colors of light. The amount of each color of light produced is controlled by selectively biasing the segments of quantum dots. The light is caused to resonate coherently and is emitted out by a diffraction grating. The dynamic variation in the color of light produced by such a device makes it useful as a multicolor pixel in a color display of images.

Abstract: A laser system includes a laser resonator cavity having a resonant axis and an Er:glass, Er:YAG, or other lasing element with an output of from about 1.4 to about 1.65 micrometers within the laser resonator cavity. A flash lamp optically pumps the lasing element to emit light. A Q-switch crystal lies along the resonant axis within the laser resonator cavity. The Q-switch crystal is formed of a host material having a concentration of U.sup.2+ ions therein, so as to be a saturable absorber of the light emitted by the lasing element. The Q-switch crystal is preferably a U.sup.2+ -doped fluoride such as U:CaF.sub.2, U:SrF.sub.2, or U:BaF.sub.2.

Abstract: A planar waveguide and a process for making a planar waveguide is disclosed. The waveguide has a layer of doped host material formed on a substrate. The host material is a trivalent material such as a metal fluoride, wherein the metal is selected from the Group III B metals and the lanthanide series rare earth metals of the Mendeleevian Periodic Table. The dopant is a rare earth metal such as erbium. The waveguide has an emission spectrum with a bandwidth of about 60 nm for amplification of an optical signal at a wavelength of about 1.51 .mu.m to about 1.57 .mu.m. The waveguide is made by forming the layer of doped host material on a substrate. The film is formed by evaporating materials from two separate sources, one source for the dopant material and a separate source for the host material and forming a film of the evaporated materials on a substrate.

Abstract: A laser resonant cavity defined by a set of reflective end elements positioned to together form a closed optical path, again medium positioned along the closed optical path, means for exciting the gain medium to produce a laser beam within the cavity, at least one focusing element positioned within the cavity in optical alignment with the gain medium, and a prism positioned as one of the end elements of the cavity and providing angular dispersion of the laser beam. The prism, end elements, gain medium, and focusing elements are positioned with respect to each other such that the resonant cavity supports a coexistence of several monochromatic laser modes, each mode having a distinct propagation axis. Propagation axes of modes having relatively longer wavelengths traverse more of the prism than propagation axes of modes having relatively shorter wavelengths, resulting in the addition of a negative component to the group velocity dispersion of the laser cavity.

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 laser produces laser emission at two or more wavelengths simultaneously. he laser includes at least two gain elements, and each gain element generates a different wavelength. A single optical pumping source is used for optically exciting all laser gain elements contained within the laser resonator cavity. A wavelength dispersing element such as a prism is disposed in the laser resonator cavity for dispersing the wavelengths operating simultaneously within the laser resonator cavity and to create separate regions for each laser gain element. Laser gain elements may be tunable laser gain elements or discretely emitting laser gain elements. Arbitrarily large wavelength separations between the wavelengths operating simultaneously may be achieved in this manner to produce stable cw or pulsed output, which may be Q-switched or line narrowed. Intracavity sum frequency generation can be produced efficiently by using a non-linear sum frequency generating crystal disposed at a laser resonator cavity waist.

Abstract: The invention provides a method and apparatus for generating high pulse energy, short optical pulses having relatively high contrast. The system comprises a diode laser to seed a compact diode pumped amplifier, and comprises pulse shaping and cleaning elements to achieve relatively high energies and high contrast. The system is not locked to a fixed repetition rate as it is controlled by an electronic trigger. The system of the invention comprises a selectively triggered pulse source (asynchronous) which is coupled to pulse amplifying/pulse shaping means, which is coupled to pulse cleaning means, which is further coupled to a chirped pulse amplification (CPA) system.

Abstract: An improved high average power, high brightness laser system. The laser system comprises an XeCI excimer amplifier, an XeCI excimer preamplifier, a means for generating a picosecond seed pulse tailored for the XeCI preamplifier and the XeCI amplifier and a means for focusing the output pulse laser beam onto a spot smaller in area than 100.times.10.sup.-6 cm.sup.2. We first produce a seed laser beam consisting of a series of bunches of short duration pulses with a bunch frequency in excess of 100 pulses per second. These seed laser pulses are produced by a Nd:YAG pumped dye laser oscillator with a cavity dumper. The pulses in the beam are preamplified in a multipass preamplifier and the pulses are then multiplexed in a pulse train generator into a larger number of lower power pulses.

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: There is described a semiconductor microcrystallite doped glass that exhibits SHG, and a method of preparing, or encoding, a semiconductor microcrystallite doped glass by the simultaneous injection of fundamental and second harmonic fields, such as 1.06 .mu.m and 532 nm. More specifically, the disclosure pertains to a structure that exhibits SHG, the structure being comprised of, by example, borosilicate glass that contains CdS.sub.x Se.sub.1-x microcrystallites. Also disclosed are embodiments of devices having an optical waveguide structure formed within a glass substrate that contains semiconductor microcrystallites. The optical waveguide structure guides and contains injected radiation and also converts a portion thereof to the second harmonic. Also disclosed are optoelectronic devices that include frequency doublers, self-doubling lasant material, bichromatic optical switches, and a volume holographic medium, all of which include a glass host having semiconductor microcrystallites embedded within.

Abstract: A host acting as an optical emitter and a process of making the same for the .sup..about. 1.3 .mu.m to .sup..about. 1.55 .mu.m spectral region utilized in optical communications is disclosed. The host is Cr-activated willemite (Zn.sub.2 SiO.sub.4). Efficient band-emission at room temperature, with peak at 1.42 .mu.m, is observed on exiting the material in the near infrared, typically at 730 nm and 829 nm.

Abstract: A fiber laser for producing high energy ultrashort laser pulses, having a positive-dispersion fiber segment and a negative-dispersion fiber segment joined in series with the positive-dispersion fiber segment to form a laser cavity. With this configuration, soliton effects of laser pulse circulation in the cavity are suppressed and widths of laser pulses circulating in the cavity undergo large variations between a maximum laser pulse width and a minimum laser pulse width during one round trip through the cavity. The fiber laser also provides means for modelocking laser radiation in the laser cavity, means for providing laser radiation gain in the laser cavity, and means for extracting laser pulses from the laser cavity.

Abstract: An optical amplifier having an amplification medium which comprises a complex of a rare earth ion and a ligand, said complex being dissolved in a polymeric matrix, as well as an optical communications network comprising one or more optical amplifiers of the above-described polymeric type.

Abstract: Apparatus and method for generating prompt X-radiation from gas clusters. The present invention includes the excitation of inner-shell electrons in the atoms comprising gas clusters using intense ultraviolet laser radiation, thereby producing intense, prompt X-ray emission from the ensemble. Clusters enable atomic excitation rates to achieve the high values characteristic of condensed matter while simultaneously eliminating, through local rapid expansion to low particle density, undesirable collisional interactions that would establish equilibrium conditions in the excited material, and effectively destroy the inner-shell specificity of the excitation. By choosing the atomic species in the cluster, the laser intensity and wavelength, and the cluster size, one can determine the wavelength of X-radiation emitted from the clusters. Moreover, by selecting the energy levels involved in the excitation process, one can produce a population inversion having significant gain and suitable for lasing.

Abstract: A fiber optical source of stimulated optical radiation comprises an optical fiber which includes a core doped with laser material having optical gain in two wavelength regions, the fiber additionally including a material in optical communication with said laser material in such a manner as to absorb radiation emitted from said laser material within one of said wavelength regions.

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: By growing semi-insulating CaF.sub.2 films (296) on a silicon substrate (240), forming superlattice structures (260) made of CaF.sub.2 :Nd and other semiconductor layers (294) and by associating a co-dopant with Nd in the CaF.sub.2 films photoluminescence efficiency of CaF.sub.2 films is increased. This permits using electrons to produce photons and controlling optoelectronic devices using CaF.sub.2 films through voltage variation.

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: Disclosed is the use of Sc.sup.2+ based active crystalline luminescent media for laser systems, tunable in the UV-visible spectral range. The crystalline media are Sc-doped alkali-earth-halide crystals such as: (1) alkali-earth-halide combinations, such as MeF.sub.2, MeCl.sub.2,crystals; (2) mixed alkali-earth metal fluorides and chlorides, such as MeFCl, M.sub.x Me.sub.1-x F.sub.2 and M.sub.x Me.sub.1-x Cl.sub.2 crystals; and (3) complex fluoride crystals; wherein M and Me are Ca, Sr, Ba or Mg. These crystals have Sc.sup.2+ ion impurities providing stable optical centers that yield advantageous luminescent properties. The base crystal structure utilized determines the luminescent emission spectrum for the Sc.sup.2+ optical centers. By manipulating the base crystal, the maxima of the absorption and emission bands may be altered from UV-blue to red in the optical spectrum. The Sc.sup.2+ active crystalline luminescent media are initially doped with trivalent Sc.sup.3+ ions during crystal growth.

Abstract: A solid-state laser comprises a pump diode for generating pump radiation and transmitting the pump radiation into a laser cavity. The pump radiation passes through an entrance mirror and enters a laser gain chip which lases to produce fundamental laser light. The fundamental laser light passes through a harmonic reflector and a first dispersive element and is frequency doubled by a frequency doubler chip to produce harmonic laser light. The harmonic laser light passes through a second dispersive element and impinges on a mirrored surface. A portion of the harmonic laser light passes through the mirrored surface to form the output beam of the laser. The remaining portion of the harmonic laser light is reflected back into the laser cavity. First and second dispersive elements control the phase of the harmonic laser light in the laser cavity such that substantially all of the harmonic laser light is in-phase when the harmonic laser light impinges upon the mirrored surface.

Abstract: A gain medium is comprised of a multi-phase system wherein: a first phase is an electromagnetic radiation emission phase; a second phase is an electromagnetic radiation scattering phase; and a third phase is a transparent matrix phase. By example, the emission phase may consist of dye molecules, the scattering phase may consist of high contrast particles, and the matrix phase may consist of a solvent such as methanol. In some embodiments of this invention the emission and scattering phases may be the same phase, as when semiconductor particles are employed. A smallest dimension of a body comprised of the gain medium may be less than a scattering length associated with the scattering phase. It is shown that nearly thresholdless laser behavior is observed in strongly scattering optically pumped dye-methanol solutions containing colloidal TiO.sub.2 or Al.sub.2 O.sub.3 ruby nanoparticles.

Abstract: The optical fiber is doped at the core thereof with Tm ions and Nd ions. When light at a wavelength in a 800-nm band for exciting the Nd ions, is incident upon the optical fiber through an incident portion thereof, the Nd ions emit light at a wavelength in the vicinity of 1,012 .mu.m. Through three excitations by absorption of light emitted from the Nd ions and/or energy transfer from the Nd ions, the Tm ions experience three excitation transitions and reach a third high energy level through first and second high energy levels. Thereafter, the Tm ions experience a radiative transition from the third high energy level, thereby to emit blue light at a wavelength of 480 nm.

Abstract: An optically-pumped or electron-beam-pumped solid-state laser employing as the phosphor material doped nanocrystal particles which as a result of quantum confinement can be caused to exhibit discrete levels in its conduction band that can overlap with the corresponding levels in the doping activator such that resonant energy transfer of excited carriers from the conduction band of the phosphor host to that of the activator will occur. The energy levels in the activator are such as to allow very fast carrier transitions to an intermediate level and a slower radiative transition to a ground state. The result is an energy level structure similar to that of a four-level laser but capable of more efficient conversion of the pumping energy to photon generation.

Abstract: A laser capable of generating polychromatic or whim light radiation is realized by employing a diffraction grating and reflecting element as the ends of a simple laser resonator cavity. The dispersive element either solely or in combination with an intracavity lens is arranged such that each wavelength component of the white light radiation is amplified by a different portion of the active medium. Forced oscillation or positive feedback for each wavelength component is achieved by operating the diffraction grating in an auto-collimation configuration.

Abstract: A monolithic self-Q-switched laser generates laser pulses with short duration, high peak power, a single longitudinal mode, and extremely small pulse-to-pulse intensity fluctuations. The laser comprises of a length of solid-state laser material with a plurality of dopants, so that the material can generate coherent radiation for laser action and, in the same material, provide saturable absorption at the wavelength of the laser emission necessary for Q-switching. The distributed saturable absorber in the material provides a spectral stabilization mechanism that ensures single longitudinal-mode operation. The laser cavity is formed by the two end surfaces of the solid-state laser material with appropriate reflectivity coatings. When the laser material is pumped above the threshold condition, the laser device produces short pulses having high peak power in a single longitudinal mode and single transverse mode.

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: A method of producing collimated x-radiation by suitably subjecting metallic ions in the presence of lower Z ions to a pulse of laser energy from a conventional laser. An improvement on said conventional laser in order to increase the reliability of production of said collimated x-radiation. An alternative improvement on said conventional laser for similar improvement of said collimated x-radiation. An example of the application of the use of said collimated x-radiation to the art of producing micro-circuitry.

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 12 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: Power laser includes a non-linear medium (NL1) within which a first beam of fixed direction (I1) and a second beam of orientable direction interfere with each other, an amplifying medium (2) placed along the direction of the first beam for amplifying the received light for transmitting an amplified beam towards the non-linear medium (NL1), which retransmits this bean in the direction of the second beam, and therefore in an orientable direction.

Abstract: A laser is capable of working at a wavelength L.sub.2 from an active material capable of generating radiating emissions at at least two wavelengths L.sub.1 and L.sub.2, through the presence of a semiconductor plate in the laser cavity. Notably, the laser can generate wavelengths ranging from 1.4 .mu.m to 2 .mu.m, a range in which the optical damage threshold of the eye is high, from an Nd.sup.3+ doped YAG having numerous radiating emission wavelengths ranging from 0.946 .mu.m to 1.8 .mu.m.

Abstract: By growing semi-insulating CaF.sub.2 films (272) on a silicon substrate (240), forming superlattice structures (260) made of CaF.sub.2 :Nd and other semiconductor layers (294) and by associating a co-dopant with Nd in the CaF.sub.2 films photoluminescence efficiency of CaF.sub.2 films is increased. This permits using electrons to produce photons and controlling optoelectronic devices using CaF.sub.2 films through voltage variation.

Abstract: A Q-switched laser having a gain medium disposed within a first resonant cavity and a second resonant cavity, sharing a common mirror with the first cavity, whose optical length is adjustable such that the quality Q of the first resonant cavity is affected. One aspect of the invention is the selection of the cavity lengths and the reflectivities of the mirrors of the first and second cavity such that Q-switched pulses of less than 100-ps duration can be obtained. Another aspect of the invention is the ability to generate said pulses with peak powers in excess of 100 kW for applications in high-precision optical radar, nonlinear optics, micromachining, microsurgery, and other applications where short pulses with high peak powers are required.

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

Abstract: A silicon-based microlaser formed of rare-earth-doped CaF.sub.2 thin films has a semiconductor substrate material (240) and a CaF.sub.2 film layers (234) grown on semiconductor substrate material (240), The CaF.sub.2 film layer (234) is doped with a predetermined amount of rare-earth-dopant that is sufficient to cause a spectral emission from the CaF.sub.2 film layer (234) having a narrow linewidth when the CaF.sub.2 film layer (234) is optically or electrically pumped.

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

Abstract: A solid state laser apparatus is provided to generate a high quality and high power laser beam, and a laser machining apparatus is provided to perform laser machining by a laser beam generated from the solid state laser apparatus. In the solid state laser apparatus, a laser resonator includes a solid state component cooled in a cylindrical pipe by contacting liquid which is introduced through an inflow opening and discharged through an outflow opening, the solid state component having larger refractive index than that of the liquid, a light source turned ON by a power source to excite the solid state component, and an optical system transmitting light from the light source to the solid state component. Further, a surface roughness of the solid state component is adjusted so as to adjust an excitation distribution in a section of the solid state component.

Abstract: A method for forming microilluminants, which comprises the steps of irradiating laser beam to microparticles doped with a laser pigment in a liquid medium, trapping the microparticles and causing these microparticles to emit light.According to this method, it is possible to form microilluminants, permitting application to new physical and chemical processes and to processing and modification of microparticles, and new developments such as optical STM.

Abstract: The present invention relates to a dye laser including a highly porous, consolidated silica sol-gel monolith having incorporated therein at least one laser dye, wherein the dye laser is substantially solvent free. The dye laser is prepared by immersing a highly porous, consolidated silica sol-gel monolith in a solution of at least one laser dye and at least one solvent until the solution enters the pores of the monolith to a significant degree to form an impregnated silica sol-gel monolith, and then drying the impregnated silica sol-gel monolith to vaporize substantially all the solvent present within the pores of the monolith.

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 thin absorbing film is bonded onto at least certain surfaces of a solid state laser gain medium. An absorbing metal-dielectric multilayer film is optimized for a broad range of incidence angles, and is resistant to the corrosive/erosive effects of a coolant such as water, used in the forced convection cooling of the film. Parasitic oscillations hamper the operation of solid state lasers by causing the decay of stored energy to amplified rays trapped within the gain medium by total and partial internal reflections off the gain medium facets. Zigzag lasers intended for high average power operation require the ASE absorber.

Abstract: A periodic dielectric structure which is capable of producing a photonic band gap and which is capable of practical construction. The periodic structure is formed of a plurality of layers, each layer being formed of a plurality of rods separated by a given spacing. The material of the rods contrasts with the material between the rods to have a refractive index contrast of at least two. The rods in each layer are arranged with their axes parallel and at a given spacing. Adjacent layers are rotated by 90.degree., such that the axes of the rods in any given layer are perpendicular to the axes in its neighbor. Alternating layers (that is, successive layers of rods having their axes parallel such as the first and third layers) are offset such that the rods of one are about at the midpoint between the rods of the other. A four-layer periocity is thus produced, and successive layers are stacked to form a three-dimensional structure which exhibits a photonic band gap.

Abstract: A pulse format for a laser system is disclosed for maximizing the energy delivered to a target immersed in an absorbing liquid. A first pulse is generated having an energy sufficient to initiate the formation of a vapor bubble in the liquid medium adjacent the end of the delivery device. A second, high energy pulse is generated after the vapor bubble initiated by the first pulse has expanded an amount sufficient to displace the liquid between the delivery device and the target. In this manner, the second pulse is delivered directly to the target and little energy is lost to the liquid medium.

Abstract: An integrated optical component structure designed to operate at a rare earth ion fluorescence wavelength .lambda..sub.1 comprises at least a thin layer of a mixed rare earth fluoride solid solution having the formula (1-x)(M.sub.1-y M'.sub.y F.sub.2)-x TRF.sub.z deposited on a substrate of a monocrystalline semiconductor material where M and M' denote an alkaline earth ion, TRF.sub.z denotes a rare earth fluoride, x is in the range ]0,1[ and y is in the range [0,1]. The component structure finds applications in telecommunications using optical waveguides.

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: The scalable and stable, cw photolytically excited atomic iodine laser operates at 1.315 nm. An initial power level of 55 watts/liter was obtained via the cw photolysis of an alkyl-iodide gas like C.sub.3 F.sub.7 I. The greatly enhanced laser performance was achieved using a microwave excited, electrodeless Hg plasma lamp excited with a d.c., low ripple cw microwave radiation. Both high flow, air cooling and liquid dimethyl polysiloxane cooling of these high pressure Hg lamps provided long lifetime operation with the latter promoting, stable laser operation. Transverse flow of the above gas for the removal of the quenching by-product I.sub.2 is incorporated into the laser. To insure good laser amplitude stability, both the high power magnetrons and the lamps are liquid cooled. The scalable, prolonged and stable operation of this laser system is possible via use of a closer cycle, condensative/evaporative fuel system coupled to a high flow, internal blower for heavy gases.

Abstract: Four-fold and higher order lasers pumped by multiphoton absorption, avalanche mechanisms, or other means of internal upconversion for continuous-wave and continuous-wave mode-locked lasers. A solid-state laser system is contained within an astigmatically compensated cavity containing first and second mirrors. The gain medium is formed of a crystal of lithium yttrium fluoride heavily doped (5%) with trivalent erbium, or another form of crystal, such as CaF.sub.2 where the dopant atoms are clustered in quartets. The crystal, in a lithium yttrium fluoride embodiment, is approximately 3 mm thick with both sides thereof being polished flat to a laser grade finish. A pumping source supplies a pumping energy having a wavelength of 1.5 .mu.m to the gain medium, which wavelength is considerable longer than the output wavelength (701.5 nm) of the laser system. The gain medium may additionally be an alkali vapor formed of Cesium or Rubidium.