Abstract: In order to make an attempt to reduce the size of the laser and to simplify the structure, in a double wavelength laser of the invention, when an optical path switching mirror 3 is located at a position where light is not reflected, emitted light of a laser diode 1 is converted into parallel light with a collimator lens 2, light is collected to an Er: YAG crystal 6 with a collector lens 4 for pumping, light output by the pumping of the Er: YAG crystal 6 is amplified with a total reflective mirror 5 and an output mirror 7 and passes through a folded mirror 8 from the output mirror 7, and light is guided to a light guide unit 10 with a collector lens 9 to be emitted outside, and when the optical path conversion mirror 3 is located at a position where light is reflected, the emitted light of the laser diode 1 is reflected in 90 degrees direction with the optical path switching mirror 3 and is guided to the light guide unit 10 with a collector lens 11 to be emitted outside.

Abstract: An ultraviolet laser source which can stably emits ultraviolet light having a sufficient output and low coherence, as a light source for an exposure unit, for a long period of time, is compact, and allows easy maintenance. The laser source is constituted by 10.times.10 laser elements, i.e., a total of 100 laser elements. Each laser element includes a laser beam emitting section for emitting light having a long wavelength, i.e., visible or infrared light, and a wavelength converting section for converting the emitted laser beam into ultraviolet light. The laser beam emitting section includes a semiconductor laser, and a solid-state laser. The wavelength converting section contains a nonlinear crystal for converting the wavelength of incident light and outputting the resultant light.

Abstract: Disclosed is an optical amplification device comprising an amplifier medium inserted between two mirrors and an optical pumping source. The mirrors are confocal mirrors whose focal plane is located in the vicinity of the center of the non-linear medium. This medium has a match-stick shape with a large axis in one direction forming an angle alpha/2 with the optical axis of the cavity defined by the two mirrors and the amplifier medium. This architecture enables an incident optical wave to pass several times within the amplification device leading to an increase in the performance characteristics of said device.

Abstract: The present invention relates to a solid-state laser which forms a high-energy and high-power laser beam with a high repetition rate and whose overall system can be optically aligned in a simple manner. The solid-state laser of the invention can be fabricated by means of reflecting the laser beam which is reflected by a phase conjugation mirror(PCM) using stimulated Brillouin scattering(SBS) in a direction that is incidented on the PCM again, concurrently with the arrangement of directions of emission and incidence of the laser beam by the aid of polarization beam splitter(PBS).

Abstract: A solid-state laser is proposed with an emission wavelength of greater than 1.4 .mu.m to eliminate the risk of damage to human skin and eyes. The proposed laser comprises: an active medium alloyed with Er.sup.3+ ions; an optical pumping source separated from the active medium by an additional filtering layer in the form of optical elements, and/or coating applied thereto, and/or a liquid medium, which intercept and eliminate ultraviolet radiation and are transparent to light in the excitation wavelength of the active medium. The cumulative internal transmission density of the filtering layer along the path of a given beam in the laser from the pumping source to the active medium, including the path in the casing of the pumping source, must be greater than 2 in the wavelength range below 320 nm and not more than 0.1 in the excitation spectrum of the active medium with wavelengths greater than 360 nm. Filtration in the laser is accomplished with the aid of, for example, a 0.3-1.5 .mu.

Abstract: Laser annealing is performed by irradiating, while scanning, a semiconductor thin-film with laser light. The laser light that is linear on the irradiation surface is moved in its line-width direction and applied non-continuously. The laser light has, in its line-width direction, an energy density profile that assumes a step-like form in which the energy density varies in a step-like manner. In particular, the scanning pitch D and the step widths L.sub.n are so set as to satisfy a relationship L.sub.n .gtoreq.D.

Abstract: A gain-switched optical distributor, i.e., commutator, is realized by employing an optical rare earth-doped fiber optical amplifier as the switching element per se. Each of the optical rare earth-doped fiber optical amplifiers acts as an ON/OFF switch. Also, the gain-switched optical distributor of this invention is a natural fit into today's optically amplified optical communication systems. In one embodiment, this is realized by employing a pump select circuit in conjunction with a plurality of pumps and a plurality of corresponding rare earth-doped fiber optical amplifiers. The particular pump and corresponding amplifier is selected by use of a monitor arrangement to determine which signal is to be selected and routed to an output. In another embodiment, a so-called tuned pump arrangement is employed in conjunction with a plurality of filters and a corresponding plurality of rare earth-doped fiber optical amplifiers.

Abstract: The present invention is an integrated, diode laser-pumped, solid state lr which can be fabricated entirely with semiconductor fabrication techniques. The laser includes a substrate, a semiconductor light source grown over the substrate to provide pump light and a solid state laser grown over the substrate. The semiconductor light source produces pump light at a wavelength useful for pumping the solid state laser. The solid state laser includes a pump mirror transparent to the pump light, an output mirror, and a doped semiconductor layer deposited between the pump and output mirrors, the semiconductor, dielectric or polymer layer being doped with active metal ions. The pump light from the semiconductor light source is closely coupled to the solid state laser and passes through the pump mirror to pump the active metal ions.

Abstract: A rare-earth doped, lithium niobate, diffusion Bragg reflector laser having a simplified structure and improved efficiency is disclosed. The laser has a pump source, a wavelength division multiplexer, a substrate of lithium niobate doped with at least one rare earth element and having a feedback element, and a grating reflector. The grating reflector is formed from portions of an optical fibre and abuts one end of the doped substrate, such that the grating reflector and the feedback element of the doped substrate form a cavity for the laser. The doped substrate may include phase or amplitude modulators for FM or AM mode-locking operation.

Abstract: At least one narrow-band emitting pump radiation source is provided in a laser arrangement having a laser medium to be pumped. The supplied pump radiation includes at least two pump radiation components which are different with respect to power. The component with lower power functions to generate a visible target beam. Such a laser arrangement is especially suitable in a medical laser system.

Abstract: A p-Ge laser operating at submillimeter wavelengths in Voigt configuration using a regular permanent magnet. The invention is improvement over prior art Ge Lasers which use superconducting magnets that require liquid helium to cool the magnets along with the Ge crystal. Although the subject invention requires cooling(refrigerant) of the Ge crystal itself, it does not need liquid helium. The permanent magnet can be Nd.sub.2 Fe.sub.14 B. The emissions using the novel invention were observed over a wider range of electric-field magnitude in Voigt configuration at a given magnetic field as compared to that of the prior system. The free space beam profile of the subject invention is Gaussian. The emission-strength of the subject invention is sufficient between 4 and 10K that a closed-cycle refrigerator can be used to cool the crystal rather than the liquid helium used in all prior p-Ge lasers.

Abstract: An optical parametric oscillator or OPO (20) includes an elongated resonant cavity (22) for signal light, having a parametric gain medium (28) disposed therein for converting pump light to signal light. The resonant cavity has a output coupling device (26) at one end thereof and a Porro prism (24) at the opposite end thereof. The OPO includes an optical arrangement (30, 39 and 40) for directing pump light to make counterpropagating initial and return passes longitudinally through the gain medium at an angle (36) to the axis (23) of the resonant cavity.

Abstract: A transverse pumping system for a laser rod uses symmetrically arranged banks of laser diodes which create overlapping patterns of illumination inside the rod. Cooling is provided by a symmetrically constructed circulation system which directs a turbulent flow of cooling water against the laser rod and against a heat sink for the diode banks. Cooling water for the laser rod flows through a glass tube surrounding the rod. This enables the cooling water to perform an auxiliary function in focussing the illumination generated by the pumping diodes.

Abstract: A solid-state laser in which a rod (10) of lasing material is held within an optical cavity formed within a cooling block (40) having a highly surface facing the rod. A longitudinal slit (44) formed in the block from the optical cavity to the outside allows the pumping light from an emission line (36) of semiconductor stripe lasers (30) fabricated on a laser bar (28) to irradiate the laser rod and multiply reflect within the optical cavity. Thereby, pump light is efficiently absorbed by the laser rod, and the laser rod is thermally controlled. Alternatively, cooling liquid (124) can flow axially along the laser rod and within an axially extending optical cavity formed by a reflective coating (125) deposited on a tube (122) enclosing the cooling liquid and having a slit (126) through which pump light is irradiated.

Abstract: An NDR diode (103) having a first electrical contact (105) and second electrical contact (111) is formed. A laser diode (113) having a third electrical contact and a fourth electrical contact is formed. The second electrical contact (111) of the negative differential resistance diode (103) is electrically coupled with the third.

Abstract: A laser system which generates pulses with a duration in the range of about 60 to 300 ps at an energy level of up to a few milli-Joules per pulse (mJ/p) with near diffraction limited beam quality. A laser crystal is pumped (excited) by diode lasers. A resonator having at least two mirror surfaces defines a beam path passing through the laser crystal. The beam path in the resonator is periodically blocked by a first optical shutter permitting pump energy to build up in the laser crystal, except for a short period near the end of each pumping period. While the first optical shutter is open a second optical shutter blocks the light in the resonator except for periodic subnano-second intervals, the intervals being spaced such that at least one light pulse traveling at the speed of light in the resonator is able to make a plurality of transits through the resonator, increasing in intensity by extracting energy from the excited laser crystal on each transit.

Abstract: A laser system is provided with a plurality of light emitting diodes arranged to energize the laser source. The individual diodes have separate controls so that they may be turned on separately from one another for different periods of time and to produce different amounts of illumination. A controller such as a CPU may be programmed to actuate the controllers in a desired manner to achieve to a controlled light profile upgrading versatility and accuracy of laser systems. In addition to sequencing individual light emitting diodes in various combinations, the diodes may be energized simultaneously in various combinations. A first combination may be illuminated for a relatively long time and a second combination energized to overlap part or all of the period of that first combination, or even to extend beyond the period of the first. Thus, in addition to adjusting pulse width time, time spacing between pulses and overlap of pulses may be adjusted as well as light amplitude of individual diode light sources.

Abstract: A temperature controlled mounting package for a fiber optic communication laser, mounted within an adapter, which is in thermal contact with a heat exchange element. The heat exchange element may be a thermoelectric cooling element or a resistance heater which maintains the laser within a temperature band. By keeping the temperature bandwidth to 40 degrees Centigrade, the signal variations are held to within 1 dB in fiber-optic applications.

Abstract: A laser system is described in which two laser elements are configured as an oscillator and an amplifier in a common optical pumping section. Oscillator element is in a resonator and a divergent oscillator output beam is steered by a steering arrangement back to the amplifier element. The divergence of the beam from the resonator is adjusted, by moving output coupler element or selecting particular curvatures of resonator mirrors for example, to match the thermal lensing power of the amplifier element so that a substantially collimated output beam is produced.

Abstract: A multi-axial mode frequency conversion system includes two resonators. At least two resonator mirrors define a first resonator cavity. A gain medium is positioned in the first resonator cavity. A pump source supplies energy to the gain medium. The first resonator cavity produces a first beam with a plurality of axial modes that are incident on a doubling crystal in the first resonator and produce a frequency doubled output beam. The first resonator cavity provides a sufficient number of axial modes to oscillate so that the doubled output beam has a noise of less than 3% RMS. At least two resonator mirrors define a second resonator cavity coupled to the output beam from the first resonator cavity. The second resonator is configured to provide resonant enhancement of at least a portion of the plurality of axial modes. A non-linear optical material is positioned in the second resonator and configured to produce a harmonic output beam.

Abstract: Apparatus performs a method of generating one output laser pulses in a range of 2 to 5 microns using an intracavity feature. When a plurality of the output laser pulses are generated, a first output pulse may have any selected wavelength within the range and a second output pulse is temporally closely spaced relative to the first output pulse and may have a chosen wavelength differing from the selected wavelength. A pump laser cavity is provided with a tunable rod and an intracavity Raman device (in the pump cavity) to shift the wavelength of initial pump laser pulses. The intracavity Raman device generates radiation at first and second Stokes wavelengths, and the pulses at each wavelength are separated and are in separate paths for permitting separate operation thereon. The Raman device in the pump cavity increases the pump intensity inside the Raman cell and gives a much longer effective interaction length between the pump laser beam and the Raman medium.

Abstract: A laser assembly includes a lasing medium (12), associated reflector components (14, 16) defining a resonance cavity, and means (16) for outputting laser pulses therefrom. Means (18) is provided to pump the lasing medium with pulses of predetermined energy. There is a pumping circuit (20) for activating the pump means, and control means (22, 34, 35) associated with said pumping circuit for determining the energy of the pumping pulses.

Abstract: A laser comprises an upconversion laser gain element made of a crystalline xide host doped with activator ions for emitting output radiation at an output wavelength. The gain element is pumped by pumping radiation at a pumping wavelength that is longer than the output wavelength. A laser resonator comprising a reflective element and an output coupler is arranged with the gain element to resonate the output radiation. The reflective element is spaced from the output coupler by a distance approaching the radius of curvature of the reflective element or the output coupler. The pumping radiation has a waist that is substantially coincident with the waist of the output radiation within the active region of the gain element.

Abstract: A tunable source of narrowband coherent radiation comprises a pulsed pump laser (10), an optical parametric oscillator or amplifier (12) and a so-called master oscillator (14). The narrowband output radiation of the master oscillator serves as seed radiation which is injected into the optical parametric oscillator or amplifier (12). In order to obtain a beam profile of the emitted output radiation as homogeneous as possible, optically imaging elements (28) are arranged in an optical delay line (24) for the partial pulses which pump the optical parametric oscillator or amplifier, which transform the spatial beam profile at the output (30) of the pump laser (10) with respect to amplitude, phase and, preferably, the divergence, too, into the crystal of the optical parametric oscillator or amplifier.

Abstract: A tunable narrowband source of a coherent radiation, comprisinga first optical parametric oscillator (OPO1) which includes at least one first optical parametric amplifier medium (K.sub.1) in a resonator (18, 20; 20, 34) or an optical parametric generator;at least one second optical parametric oscillator (OPO2) which includes at least one second optical parametric amplifier medium (K.sub.

Abstract: A solid-state lasers 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. Further described is an excimer lamp that has the capability of provided illumination at varying wavelengths. In one embodiment an excimer is selected in a desire to maximize light absorption in plants. This is accomplished by tuning the lamp to provide an output compatible with plant chlorophyll.

Abstract: This invention encompasses generating electromagnetic solitary waves in two-transverse spatial dimensions. These wave beams propagate without diffraction and are equivalent to the normal modes of propagation of a nonlinear system governed by second order optical nonlinearities. The wave beams can be generated using optical techniques and will impact a wide variety of geometries and operating conditions whenever second order nonlinear optical processes are implemented for harmonic and parametric optical conversion. A preferred embodiment covers the generation of solitary waves from nonlinear materials such as KTiOPO.sub.4 (KTP) crystals. Other types of nonlinear optical device crystals can also be used such as KH.sub.2 PO.sub.4 (KDP), (NH.sub.2).sub.2 CO(Urea), LiNbO.sub.3, KNbO.sub.3, and the borate crystals BaB.sub.2 O.sub.4 (BBO) and LiB.sub.3 O.sub.7 (LBO).

Abstract: A stabilized atomic clock system uses a stabilized 780.2 nm pump laser for exciting rubidium-85 atoms fluorescing to optically pump rubidium-87 atoms both contained in a gas cell enclosed in a resonant microwave cavity for broadcasting a 6834.7 MHz microwave signal matched to Rb87 hyperfine ground states which are insensitive to pump laser wavelength fluctuations of the pump laser providing the fluorescence optical pumping of the Rb87 atoms to create a population imbalance sensed by a stabilized 794.7 nm probe laser transmitting a probe beam through the cell to a probe laser photodetector generating a probe laser signal used to stabilize the microwave signal to the atomic system and used to generate a constant frequency tick rate signal that is consequently insensitive to pump laser frequency drift due to reduced light shift coefficient.

Abstract: A high power diode pumped laser is disclosed which has at least one resonator mirror and an output coupler. At least one laser crystal with strong thermal focussing properties is included. The laser includes at least one diode pump source supplying a pump beam to the laser crystal, producing a thermal lens in the laser crystal. The combination of the laser crystal, thermal lens, resonator mirrors and output coupler create a confocal-to-concentric resonator. An output beam is generated, which may be polarized. Further, a Q-switch may be included in the resonator, particularly when the laser crystal is Nd:YAG.

Abstract: This invention relates to a diode pumped slab laser in the form of a slab where two opposite faces are adapted to receive pumping radiation with the faces being cut at the Brewsters angle at one end to provide entrance/exit faces for the lasing radiation. The laser radiation beam follows a zig-zag path in the slab and is contained within the slab by total internal reflection. The laser slab is contained within an optical cavity which results in the laser beam completing a double zig-zag beam path. The design results in good pump/mode matching, mitigates thermally induced birefringence problems, overcomes amplified spontaneous emission problems, requires no coatings or curved surfaces, and is easy and relatively inexpensive to make. The slab can be used within both Quasi-CW and CW modes.

Abstract: A low noise optical fiber Raman amplifier with integral Raman laser (FRA) is disclosed. The FRA typically comprises a fiber ring with at least two amplifier stages, with strictly counter-propagating pump radiation. Relatively short wavelength (e.g., 1060 nm) pump power is provided to the Raman laser portion of the fiber ring. Appropriately selected and placed Bragg gratings provide one or more optical cavities in the fiber ring, such that the input pump radiation is converted to the desired amplifier pump radiation (e.g., 1240 nm, suitable for amplification of 1310 nm signal radiation). The FRA can, for instance, advantageously serve as power amplifier in digital or analog fiber communication systems, or it can serve as pre-amplifier or in-line amplifier.

Abstract: An conversion laser design for the generation of blue light incorporates fiber Bragg gratings, mode-matching fibers, pump noise reduction, pump combining, and a self-oscillating pumping scheme, allowing the use of a single wavelength pump laser to pump through a cross-relaxation method of Yb.sup.3+ to Pr.sup.3+, as well as a self-oscillating pumping method. The use of narrowband mirrors, such as FBGs, is also disclosed for the upconversion laser to allow suppression of parasitic oscillators.

Abstract: An apparatus and method for energy conversion of laser light with optical paramedic oscillation with reduced threshold and improved efficiency. A laser and an optical parametric oscillator are combined so that they share the same optical cavity. The laser field in the cavity is used as the seeding wave for the optical nonlinear material in converting the input pump wave into signal and idler waves, the idler wave having a frequency substantially identical to the laser frequency.

Abstract: A dual wavelength pumped low noise fiber laser includes a fiber laser 10 comprising a pair of Bragg gratings 14,16 at opposite ends of a fiber laser cavity 18 which is co-doped with two rare-earth dopants, Er.sup.+3 Yb.sup.+3, so as to allow lasing to occur at a lasing wavelength .lambda..sub.L. A first pump signal 20 efficiently pumps the Yb to the excited state and the Yb energy is transitioned to the Er atoms which ultimately lase at the desire lasing frequency. Because Yb is pumped so efficiently, high pump absorption is achieved, thereby providing high laser output power and, consequently, reduced RIN. Simultaneously, a second pump signal 52 directly pumps the Er at a different wavelength .lambda..sub.P2 which populates the lasing transition more quickly, thereby allowing sufficient bandwidth of a closed loop control on the second pump signal 52 to control low frequency RIN spiking due to relaxation oscillations in the laser.

Abstract: A gas laser consisting of a single elongated piece of dielectric material (1), with two hermetically sealed parallel elongated chambers (2) and (3), and an opening (4) connecting the two chambers. One of the elongated chambers (2) is of a cross section suitable for confining a laser gas discharge. The other elongated chamber (3) is a reservoir for laser gas, which also functions to dampen the unwanted acoustic waves generated by the laser gas discharge and as a means of extending the operating lifetime of the laser gas. The opening connecting the two elongated chambers serves to dampen the acoustic waves generated by the laser gas discharge traveling the length of the elongated laser chamber and to stop unwanted low angle wall reflections of laser light energy traveling at a slight angle to the length of the laser chamber.

Abstract: The present invention is a laser with a high reflector mirror and an output coupler mirror defining a laser resonator having an optical axis and optical path length. A gain medium, with a first refractive index and a first Verdet constant, is positioned in the resonator. The laser also includes an apparatus to excite and cause a population inversion in the gain medium to produce an output laser beam. An optically transparent medium is positioned in the laser resonator. The optically transparent medium has a second refractive index and a second Verdet constant. The second Verdet constant is typically larger than the first Verdet constant. One or more permanent and electromagnets are positioned at least partially around the exterior of the laser resonator.

Abstract: A compact fission reactor generates a flux of fission fragments, fission neutrons, and gamma-ray photons. The flux excites a noble element converter medium which produces light. Optical means are provided for focusing the light onto an array of photovoltaic cells. The photovoltaic cells convert the light radiation into electrical energy for various load applications.

Abstract: Apparatus performs a method of generating one or more output laser pulses in a range of 2 to 6 microns. When a plurality of the output laser pulses are generated, a first output pulse has any selected wavelength within the range and a second output pulse is temporally closely spaced relative to the first output pulse and has a chosen wavelength differing from the selected wavelength. An oscillator laser cavity is provided with a tunable oscillator rod capable of generating initial laser pulses within a range of from 750 to 1000 nm, and a tuning element is coupled to the rod. A flashlamp is operable to pump the rod. For two pulse operation, the flashlamp has a given duration. A Q-switch provides the initial laser pulses upon operation of the tuning element and the flashlamp. A Raman device coupled to the rod shifts the wavelength of such initial laser pulse into the range of from 2 to 6 microns to form the output laser pulse having a wavelength within the range.

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: 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 pulsed laser comprises an oscillator (10), a laser medium (14), a wavelength selective member (12) for tuning the wavelength of a beam pulse (18) emitted by the oscillator, and means for pulsed excitation of the laser medium (14). The laser medium (14) is excited at least twice at consecutive times to generate a single beam pulse (18).

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: An optically pumped bistable laser (LAS) with an active laser condition and an excited inactive condition is presented. The bistable laser (LAS) comprises an erbium-doped fiber (ER), a resonator (RES), a pumping light source (PUMP), and optical isolator (ISO), a wavelength-dependent coupler (WDM) and an asymmetrical fiber coupler (FC). Excitation from the excited condition is created by pumping light from the pumping light source (PUMP) into the erbium-doped fiber (ER), to place the bistable laser into the excited inactive condition. Optical pulses, which are coupled in through input (IN), activate the bistable laser (LAS) and enable it to operate both as a pulse generator and a trigger circuit, as a function of pulse duration and/or pulse frequency.

Abstract: The improved metal vapor laser capable of cold operation performs plasma etching on a vaporizing metal within a laser tube in the presence of a reactive gas so that the metal is vaporized at temperatures below its boiling point to effect laser oscillation. The laser can be operated at much lower temperatures than a conventional hot-operating version which produces metal vapors by thermal evaporation; in addition, the laser will experience a smaller heat loss while undergoing limited thermal damage to its structural members; further, laser light can be oscillated to produce high output power and, at the same time, the warmup time can be shortened significantly.

Abstract: High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes.

Abstract: A laser device includes a laser rod; a dielectric coolant tube around the laser rod, forming an annular rod coolant channel; a segmented conductive ring around the coolant tube with laser diodes between adjacent ring segments; the ring segments and laser diodes together forming a current path around the ring; and a sleeve around the ring, forming an annular diode coolant channel.

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: An immersion cooled semiconductor laser assembly includes an electrically activated semiconductor laser device, such as a two-dimensional laser diode array, and liquid coolant flowing thereabout which directly contacts the emitting facet of the semiconductor laser device. The semiconductor laser assembly also includes first and second electrodes for supplying electrical energy to the semiconductor laser device such that the semiconductor laser device emits a laser output through its emitting facet. During the emission of the laser output, however, the semiconductor laser device generates heat, thereby increasing the temperature of the semiconductor laser device. In order to protect the semiconductor laser device, the circulating liquid coolant draws heat from the semiconductor laser device, thereby cooling the semiconductor laser device.

Abstract: A high average power, high brightness solid state laser system. We first produce seed laser beam with a short pulse duration and frequency in excess of 1,000 pulses per second. A laser amplifier amplifies the seed pulse beam to produce an amplified pulse laser beam which is focused to produce pulses with brightness levels in excess of 10.sup.11 Watts/cm.sup.2. Preferred embodiments produce an amplified pulse laser beam having an average power in the range of 1 kW, an average pulse frequency of 12,000 pulses per second with pulses having brightness levels in excess of 10.sup.14 Watts/cm.sup.2 at a 20 .mu.m diameter spot which is steered rapidly to simulate a larger spot size. These beams are useful in producing X-ray sources for lithography.In one preferred embodiment, the seed beam is produced in a mode locked Nd:YAG oscillator pumped by a diode array with the frequency of the pulses being reduced by an electro-optic modulator.