Abstract: An array of devices for electronically steering a laser beam. A plurality of quantum well absorption modulators steer a laser beam, either reflective or transmissive, without moving parts and operable at room temperature. The foregoing is accomplished using intraband, also termed intersubband transitions in the quantum wells.

Abstract: A system is provided for passively producing at least two distinct signal patterns. The system can be used for passively identifying friend or foe in an environment and operates in a hyper spectral mode that accommodates multiple bands simultaneously. Exemplary embodiments receive radiated energy within a resonant cavity, and use an absorber and a reflector to absorb and reflect desired frequencies of the incoming energy. A controller is connected to the IFF system and controls the switching back and forth between the absorber and the reflector to produce a signal having a desired data format. The encoded data can be used to determine the status of the candidate target.

Abstract: A passive Q switch. The inventive Q switch includes a first wedge of material adapted to absorb electromagnetic energy. The first wedge has a first thickness on a first end thereof and a second thickness on a second end thereof diametrically opposite the first end. The first wedge has a first surface connecting the first and second ends and a second surface connected the first and second ends. The second surface is slanted relative to the first surface. A second wedge of material is included in the inventive passive Q switch. As per the first wedge, the second wedge has a first thickness on a first end thereof and a second thickness on a second end thereof diametrically opposite the first end. The second wedge has a first surface connecting the first and second ends and a second surface connecting the first and second ends. The second surface is slanted relative to the first surface.

Abstract: A repetitively pulsed chemical oxygen-iodine laser having a resonant cavity containing a lasing medium in the form of a flowing mixture of excited oxygen and iodine atoms and an iodine absorption region within the resonant cavity. The iodine absorption region includes a source of iodine atoms and a magnetic field associated therewith. Selectively altering the magnetic field results in changing the absorption characteristics of the iodine atoms and therefore effectively pulses the output of the laser.

Abstract: A passively mode-locked solid-state laser for emitting a continuous-wave train of electromagnetic-radiation pulses, the fundamental repetition rate of the emitted pulses exceeding 1 GHz, without Q-switching has an optical resonator, a solid-state laser gain element placed inside the optical resonator, an exciter for exciting said laser gain element to emit electromagnetic radiation having the effective wavelength, and a saturable absorber for passive mode locking. The laser gain element preferably consists of a laser material with a stimulated emission cross section exceeding 0.8×10−18 cm−2 at the effective wavelength. Typically, the laser gain element is made of Nd:vanadate. The saturable absorber is preferably a semiconductor saturable absorber mirror device. The laser is simple, robust, compact, efficient, and low-cost.

Abstract: A laser transmitter assembly of the present invention is configured for placement within a firing chamber of a user firearm and to have minimal interference with a firearm extractor during charging of the firearm. The laser assembly emits a beam of laser light toward a firearm laser training system target in response to actuation of the firearm trigger to simulate firearm operation. Further, the laser assembly is manufactured to project a concentric laser beam relative to the firearm barrel, thereby enabling use without having to align the assembly with the firearm bore sight.

Abstract: A Q-switched microlaser is provided that is capable of supporting a zig-zag resonation pattern in response to side pumping of the active gain medium so as to effectively lengthen the microresonator cavity without having to physically lengthen the microresonator cavity. As such, the microlaser can generate pulses having greater pulse widths and correspondingly greater pulse energies and average power levels than the pulses provided by conventional microlasers of a similar size. A corresponding fabrication method is also provided according to one embodiment of the present invention that permits a plurality of side pumped Q-switched microlasers to be fabricated in an efficient and repeatable manner.

Abstract: A sub-nanosecond passively Q-switched microchip laser is disclosed. It combines an optically pumped, passively Q-switched, high-frequency, microchip laser producing short pulses with an optically end-pumped amplifier producing high small-signal gain while pumped at low power. The microchip laser for emitting pulsed laser radiation is a monolithic body comprising two reflective elements defining an optical resonator for laser radiation, a laser gain medium, e.g., Nd:YAG, and a saturable absorber medium, e.g., Cr4+:YAG placed inside said resonator. The optical amplifier stage for amplifying the laser radiation comprises an amplifying medium, e.g., Nd:YVO4. The microchip laser and the amplifier are optically end-pumped, preferably by high-brightness diodes. This entirely passive laser system directly produces &mgr;J pulses at repetition rates of about 45 kHz.

Abstract: A semiconductor optical pulse compression waveguide with a novel structure that can greatly reduce its size, and be simply fabricated. The semiconductor optical pulse compression waveguide is composed of a semiconductor optical waveguide which guides an optical signal and includes an optical pulse compression region. The optical pulse compression region includes at least one saturable amplifier region that loses its amplification characteristic after amplifying a fixed amount of optical energy, and at least one saturable absorber region that loses its absorption characteristic after absorbing a fixed amount of optical energy, where the saturable amplifier region and the saturable absorber region are disposed alternately in series in the optical pulse compression region.

Abstract: The invention is a frequency stabilized passive Q-switch laser, which has the advantages of small volume, simple structure, no need for high power voltage, etc. It has been a long time that timing jitter in conventional lasers is so large that they can not be applied to fields such as distance measurement. This invention utilizes an optical external modulation method to stabilize the repetition rate of the passive Q-switch, and thus to decrease its timing jitter. At the same time, the repetition rate of the Q-switch laser can be controlled by the same technology to meet various application needs.

Abstract: An eyesafe, Q-switched, laser system for target identification, ranging, and gated viewing purposes features a Resonant Pumped Erbium (RPE) laser, which exhibits a longer storage lifetime that minimizes the number of diodes needed to pump optical parametric oscillators (OPOs) or Raman converters. The RPE laser is in band to I2 devices.

Abstract: A laser utilizes a cavity design which allows the stable generation of high peak power pulses from mode-locked multi-mode fiber lasers, greatly extending the peak power limits of conventional mode-locked single-mode fiber lasers. Mode-locking may be induced by insertion of a saturable absorber into the cavity and by inserting one or more mode-filters to ensure the oscillation of the fundamental mode in the multi-mode fiber. The probability of damage of the absorber may be minimized by the insertion of an additional semiconductor optical power limiter into the cavity.

Abstract: A Q-switched laser, which is pumped by at least one pump source (8), providing pulses. The laser comprises two mirrors (3,5) providing a laser cavity, in which a gain medium (2), a saturable absorber (4) and a controllable active modulator (6) is situated. Loss can be introduced in the modulator (6) by a control device (10). In a first phase, said control device (10) introduces loss in the active modulator, setting a threshold inversion density band to a level (B) high enough to be above the actual inversion density in the gain medium means. In a second phase, the control device lowers said loss instantly, which will lower the threshold inversion density band to a level (A) lower than the actual inversion density in order to activate emission of said Q-switched pulse.

Abstract: An intracavity resonant Fabry-Perot saturable absorber (R-FPSA) induces modelocking in a laser such as a fiber laser. An optical limiter such as a two photon absorber (TPA) can be used in conjunction with the R-FPSA, so that Q-switching is inhibited, resulting in laser output that is cw modelocked. By using both an R-FPSA and a TPA, the Q-switched modelocked behavior of a fiber laser is observed to evolve into cw modelocking.

Abstract: A Q-switched semiconductor laser is supposed to facilitate high-frequency laser modulation with low currents or voltage ranges. According to the invention, a laser of this type consists of at least one continually pumped active medium and two optically coupled resonators at least one of which is passive, both resonators having different mode combs corresponding to the Nonius principle, at least one resonator mirror taking the form of a reflector with strongly dispersive reflection characteristics in the laser wavelength range selected by the double resonator, the index of refraction of the passive resonator and/or reflector capable of being adjusted electronically.

Abstract: A compound planar waveguide comprising multiple confinement structures that provides independent containment of pump and laser radiation. The waveguide may be formed of multiple layers of laser-active and laser-inactive materials to provide step changes in refractive index. The planar waveguide may include a central laserable core layer substantially sandwiched by at least two non-laserable cladding layers to provide an interface between the inner surfaces of the cladding layers and the gain medium core to define a first waveguide by virtue of an index of refraction discontinuity for containing developed laser radiation, and wherein the outer surfaces of the cladding layers define a second waveguide by virtue of an index of refraction discontinuity for containing pump radiation within the waveguide. The second waveguide may be also defined by an interface formed between the cladding layers and additional non-laserable external layers which sandwich the cladding layers.

Abstract: The present invention is an improved modelocked laser comprising an optical gain medium and an optical cavity including a self-tuning saturable reflector incorporating one or more quantum wells. In the improved laser, the self-tuning saturable reflector comprises a first Bragg grating having a reflection spectrum broader than the spectrum of desired lasing and an additional Bragg reflector for light in the spectral region of lasing to provide self-starting and stable operation without mechanical tuning. The Bragg reflectors are preferably semiconductor quarter wave reflector stacks, and the saturable absorber is one or more quantum wells within the outer stack. The invention also encompasses the new saturable reflector used in such lasers.

Abstract: An optical functional amplifying device suitable for use in an optical gate which operates at a very high repetition frequency such as a frequency exceeding 100 GHz. The device has a semiconductor laser amplifier having a gain section and a saturable absorber section, a first optical coupler for coupling an input signal optical pulse train having a wavelength whose value is set near the absorption edge of the saturable absorber section in the semiconductor laser amplifier, a second optical coupler for coupling a gate optical pulse train having a wavelength shorter than that of the input signal optical pulse train to the semiconductor laser amplifier, and a selector for separating and extracting a signal optical pulse train emitted from the semiconductor laser amplifier from the gate optical pulse train.

Abstract: A method and apparatus for inducing a loss or gain grating in a saturable medium, and the application of this induced grating to provide optical signal processing functions to a lightwave communications signal. The method and apparatus provides self-tuning noise filtering and self-adjusting channel equalization of lightwave communication signals using a single-mode guided wave structure including a saturable medium, the medium having a first and second end, a reflector at the first end of the medium, and an input/output port at the second end of the medium such that light entering the input port interferes with light reflected off said reflector to create an interference induced grating.

Abstract: Stable operation of an ultra-compact modelocked fiber laser generating short optical pulses generally without use of any non-fiber, intra-cavity polarization-manipulating elements is obtained by employing a saturable absorber coupled to one end of a highly-birefringent fiber serving as the laser cavity. Once the laser is modelocked in one of the polarization axes of the highly-birefringent fiber, the degeneracy of the polarization axis is eliminated and cw oscillation along the other polarization axis is also prevented. Without a polarization-dependent loss in the cavity, the modelocked polarization axis is indeterminate, i.e., modelocking can occur on either of the polarization axes. However, the introduction of only a small polarization dependent loss is sufficient to ensure the reliable start-up of modelocking on only the low-loss axis.

Abstract: The object of the present invention is to provide a variable wavelength semiconductor laser which is large in ontinuous variable wavelength width, simple and convenient in structure, easy to produce, monolithic and small in size, and easy to handle. The variable wavelength semiconductor laser includes an optical gain region formed from two-dimensional or three-dimensional carrier confinement structures having sizes approximately of a thermal de Broglie wavelength whose size dispersion is controlled so that a gain spectrum covers a required variable wavelength region for generating and amplifying light when current is injected, a light absorption control region having a light absorption coefficient which varies depending upon a current injection amount, an optical resonator including the optical gain region and the light absorption control region, and control means for controlling current amounts or voltage values to be injected to the optical gain region and the light absorption control region.

Abstract: A high powered solid-state laser apparatus that is small in size and low in cost. The solid-state laser apparatus includes a semiconductor laser, a laser crystal, an etalon element, a non-linear wavelength converting element, and an output mirror, which are used to reduce the number of the fundamental wave length mode pieces, thereby raising an efficiency of the Q-switch. Thus, an output power of the laser is increased.

Abstract: The invention relates to a microlaser cavity (10) having:a solid active medium (2) emitting at least in a wavelength range between 1.5 and 1.6 .mu.m, anda saturable absorber (4) of formula CaF.sub.2 :Co.sup.2+ or MgF.sub.2 :Co.sup.2+ or SrF.sub.2 :Co.sup.2+ or BaF.sub.2 :Co.sup.2+ or La.sub.0.9 Mg.sub.0.5-x Co.sub.x Al.sub.11.433 O.sub.19 or YAlO.sub.3 :Co.sup.2+ (or YAl.sub.5-2x Co.sub.x Si.sub.x O.sub.3) or Y.sub.3 Al.sub.5-x-y Ga.sub.x Sc.sub.y O.sub.12 :Co.sup.2+ (or .sub.-3 Al.sub.5-x-y2z Ga.sub.x Sc.sub.y Co.sub.z Si.sub.z O.sub.12) or Y.sub.3-x Lu.sub.x Al.sub.5 O.sub.12 Co.sup.2+ (or Y.sub.3-x Lu.sub.x Al.sub.5-2y Co.sub.y Si.sub.y O.sub.3) or Sr.sub.1-x Mg.sub.x La.sub.y Al.sub.12-y O.sub.12 :Co.sup.2+ (or Sr.sub.1-x Mg.sub.x-y Co.sub.y La.sub.z Al.sub.12-z O.sub.12, with o<y<x).

Abstract: A monolithic, non-planar ring laser having Q-switched single-frequency operation comprises a diode laser as the pumping light source of which the pumping light is coupled to a ring laser crystal (2) that comprises at least three total reflection faces B, C and D and a dielectrically coated crystal face A designed as a coupling and decoupling mirror. To obtain high-power laser pulses in the highly stable single-frequency mode and further to achieve compactness, the following design solutions are offered: 1. A switching crystal (20) having an appropriate index of refraction which can be moved to a distance of about one laser beam wavelength to one of the total reflection faces B, C, D of the ring laser crystal (2) to decouple the evanescent wave field and thereby to suppress laser oscillation, said switching crystal being displaceable away from the total reflection face to generate laser pulses, 2.

Abstract: An eyesafe laser (10) transmitter having a single resonator cavity (16) for both the pump laser and the optical parametric oscillator (22). A Nd:YAG rod (24) provides gain for light at a first wavelength. A combined Q-switch/Brewster plate (26) Q-switches the light to increase its intensity and polarizes the light so that its polarization plane is perpendicular to the Z-axis of a KTP crystal functioning as the optical parametric oscillator, thereby providing type II phase matching conditions. The optical parametric oscillator transforms the light at the first wavelength to light at a second wavelength which is output thorough a partially reflective outcoupler at a wavelength which will not harm the eyes.

Abstract: A solid state saturable absorber (SSSA) is formed from a slab of solid state material, such as Cr.sup.4+ : YAG. Optical distortion caused by the absorption process can be minimized by confining absorption to portions of the solid state slab which can be cooled efficiently. In accordance with an important aspect of the invention, the use of the SSSA in accordance with the present invention allows the repetition rate, pulse width, and energy level of the laser output pulses to be controlled by way of optical pump sources, such as a diode array. The solid state slab material allows for zig-zag propagation and thus, averaging of the thermal gradients caused by absorption, optical pumping and cooling which results in relatively low thermal lensing with virtually no birefringence and therefore allows for passive Q-switching applications in relatively high brightness laser systems.

Abstract: A pulsed solid-state laser comprises an optical resonator and a solid-state laser medium placed inside the optical resonator. A saturable absorber, such as a semiconductor saturable absorber mirror device for passive mode locking is placed inside the optical resonator, and a pumping source is provided for exciting the laser gain medium to emit electromagnetic radiation. The pumping source emits pump radiation which impinges on the laser gain medium in the form of a non-diffraction-limited focused pumping beam. The product of the stimulated emission cross section times the spontaneous fluorescence lifetime is low for the laser medium, e.g., 0.1.multidot.10.sup.-23 cm.sup.2 s for Ti:sapphire; nevertheless, the laser yields a high output power of a few Watt even if pumped with a non-diffraction-limited pumping beam. Pumping with a non-diffraction-limited pumping beam makes feasible solid-state lasers with remarkably smaller sizes and lower costs, but with the same performance as known lasers.

Abstract: Microlaser cavity and externally controlled, passive switching, pulses solid microlaser including a saturable absorber 46 and a device (60, 62) for introducing a beam 56 into the microlaser cavity initiating or starting saturation of the saturable absorber.

Abstract: An eyesafe laser (10) transmitter having a single resonator cavity (16) for both the pump laser and the optical parametric oscillator (22). A Nd:YAG rod (24) provides gain for light at a first wavelength. A combined Q-switch/Brewster plate (26) Q-switches the light to increase its intensity and polarizes the light so that its polarization plane is perpendicular to the Z-axis of a KTP crystal functioning as the optical parametric oscillator, thereby providing type II phase matching conditions. The optical parametric oscillator transforms the light at the first wavelength to light at a second wavelength which is output thorough a partially reflective outcoupler at a wavelength which will not harm the eyes.

Abstract: An eyesafe laser system includes a Q-switch crystal formed of a semiconductor host material having noncentrosymmetric tetrahedral substitutional sites doped with transition metal ions in concentrations from about 0.001 to about 0.10 atomic percent, which functions as to be a saturable absorber of light at eyesafe wavelengths with a relatively long relaxation lifetime. Co.sup.2+ :ZnSe has been demonstrated to have advantageously high absorption cross section and advantageously high relaxation lifetime at both 1.54 .mu.m (Er:glass laser) and 1.6 .mu.m (Er:YAG laser). Other candidate host materials include other zinc chalcogenides, cadmium chalcogenides and zinc oxide.

Abstract: A laser system includes a laser resonator cavity having a resonant axis and a lasing element within the laser resonator cavity. The lasing element emits, under stimulation, light at a wavelength of from about 1.6 to about 2.3 micrometers. There is a flash lamp, laser diodes or other pumping devices, which optically pump the lasing element to emit laser 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 Ho.sup.3+ ions therein, so as to be a saturable absorber of light of a wavelength of about 2.0-2.1 micrometers. The Q-switch crystal is preferably Ho.sup.3+ -doped yttriumlithium-fluoride, or Ho.sup.3+ -doped yttrium-vanadate. In another embodiment, the Q-switch crystal is preferably Cr.sup.2+ :fosterite (Mg.sub.2 SiO.sub.4).

Abstract: The mode-locked laser with improved pulse power output can be realized by combining an optical oscillator with a flared CW or modulated gain amplifier. An optical filter or isolator may be disposed between the oscillator and amplifier to avoid feedback of spontaneous noise. A two-segment laser is devised by providing a flared gain section between a modulated gain section and an absorber section within the integrated semiconductor laser. The flared section may taper from a larger modulated gain section to a smaller cross section absorber section or vice versa. Various combinations of absorber sections coupled to modulated gain sections by CW gain or passive flared gain sections may be combined with various arrangements of reflectors and tapered CW gain amplifiers are cascades of such amplifiers and modulated gain pairs.

Abstract: A tunable laser whose lasing frequency can be changed by varying the absorbance of absorber layers that are preceding a standing wave of the laser cavity. Changes in the absorbance of the layers are accomplished by varying the strength of the absorber layers through application of voltage to the layers.

Abstract: A laser system includes a laser resonator cavity having a resonant path and an Er,Yb:glass lasing element with an output of from about 1.5 to about 1.6 micrometers within the laser resonator cavity. A diode array optically pumps the lasing element to emit light. A Q-switch lies along the resonant path within the laser resonator cavity. The Q-switch is formed of a host material having a concentration of uranium ions therein, so as to be a saturable absorber of the light emitted by the lasing element. The Q-switch is preferably a uranium-doped fluoride such as U:CaF.sub.2, U:SrF.sub.2, or U:BaF.sub.2.

Abstract: The generation of ultrashort pulses with adjustable repetition rates from passively modelocked fiber lasers is demonstrated. By inserting semiconductor saturable absorbers with life-times of the order of 10 nsec into fiber lasers with cavity round-trip times of the order of 100 nsec, passive harmonic modelocking is obtained, leading to the stable generation of pulses at integer multiples of the fundamental cavity frequency. For polarization states that allow for optical limiting of the lasers, pulses are obtained in a frequency range between 20 and 500 MHz., where different repetition rates can be simply selected by changing the pump power level to the cavity. The pulse jitter within one cavity round-trip time is measured to be between 300 psec and 50 psec, where side bands in the frequency domain may be suppressed by up to 70 dB.

Abstract: A wavelength-conversion solid-state laser capable of generating a ultraviolet laser beam with high efficiency. The wavelength-conversion solid-state laser is made up of a phonon-based solid-state laser crystal, a semiconductor laser which emanates pump light to pump the phonon-based solid-state laser crystal, a laser resonator, a wavelength selection element which selects an oscillation wavelength, and a nonlinear optical crystal which generates a sum frequency of a solid-state laser beam, whose wavelength is selected by the wavelength-selection element, and the pump light. The phonon-based solid-state laser crystal is pumped with pump light emitted from the semiconductor laser, as a result of which a solid-state laser beam is emitted. A sum frequency of the solid-state laser beam and the pump beam is produced by enabling them to pass through the nonlinear optical crystal.

Abstract: A laser resonant cavity employs a dye sheet Q-switch disposed to receive the output of a laser and a Cr.sup.4+ :YAG Q-switch disposed adjacent the dye sheet Q-switch. Disadvantageous aspects of either Q-switch when used alone are eliminated, resulting in higher output energy and overall efficiency. A new Q-switch employing a dye sheet sandwiched between a pair of Cr.sup.4+ :YAG plates is also disclosed.

Abstract: A laser system includes a laser resonator cavity having a resonant axis and a lasing element within the laser resonator cavity. The lasing element emits, under stimulation, light at a wavelength of from about 0.95 to about 1.65 micrometers. There is a flash lamp which 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 Co.sup.2+ ions therein, so as to be a saturable absorber of light of a wavelength of from about 0.95 to about 1.65 micrometers. The Q-switch crystal is preferably Co.sup.2+ -doped yttrium-scandium-gallium garnet or Co.sup.2+ -doped yttrium-aluminum garnet.

Abstract: A glass fiber laser system includes a laser resonator cavity having a resonant path and an erbium-doped glass fiber lasing element with an output of from about 1.5 to about 1.6 micrometers within the laser resonator cavity. A light source directed into an input end of the glass fiber lasing element optically pumps the lasing element to emit light. A passive Q-switch lies along the resonant path within the laser resonator cavity. The Q-switch is formed of a host material having a concentration of uranium ions therein, so as to be a saturable absorber of the light emitted by the lasing element. The Q-switch is preferably a uranium-doped fluoride crystal such as U:CaF.sub.2, U:SrF.sub.2, or U:BaF.sub.2.

Abstract: A method of using a distributed saturable absorber added to a laser cavity, which by nonlinear wave-mixing of the counterpropagating beams (or spatial hole-burning) promotes a reduction of the linewidth and a single mode operation.

Abstract: A technique for the generation of picosecond (psec) and femtosecond (fsec) pulses from modelocked double-clad fiber lasers cladding pumped with broad area diode laser arrays is disclosed. Using an erbium/ytterbium fiber oscillator, 560 fsec pulses with pulse energies up to 40 pJ are generated at a wavelength of 1560 nm. In a dispersion-compensated cavity, pulses as short as 170 fsec with pulse energies up to 50 pJ are obtained. By adding a negatively chirped fiber Bragg grating for additional intracavity dispersion control, pulse widths of 3 psec with pulse energies up to 1 nJ are obtained. A saturable absorber is used for pulse start up, whereas nonlinear polarization evolution is exploited for steady-state pulse shaping. An environmentally stable design is ensured by employing birefringent fibers and a compensation scheme for linear and nonlinear polarization drifts in the cavity.

Abstract: A broadband thermal optical limiter disposed between a laser oscillator and laser amplifier system for protecting optical components in the laser oscillator from damage due to amplified optical feedback from the laser amplifier system at all near ultraviolet, visible and near infrared wavelengths is disclosed.

Abstract: A laser including a resonant cavity having a solid amplifier medium (1, 7, 8), an inlet mirror (2, 9, 10), an outlet mirror (3, 11, 12, 21), and an optical pumping device (5, 13, 16) to emit at least one pumping beam from the amplifier medium. The laser is operable to vary the direction of the pumping beam in the amplifier medium, and the cavity possesses a geometry enabling a laser beam to be generated, irrespective of the direction of the pumping beam.

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 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: Apparatus for extracting heat from objects such as a slab laser having an accessible flat surface subject to being heated and including a flat strip of material, preferably made from wafer grade semiconductor, such as silicon or gallium arsenide, and mounted in close proximity to the surface so as to leave a small gap therebetween of uniform thickness over an area of said surface to be cooled. A still gas fills the volume of the gap which is sufficiently small that the gas serves as an effective heat transfer medium from said surface to said strip from which heat is transferred to a medium mounted in thermal contact with the strip on the side away from said surface being cooled. The invention has particular application to the cooling of slab lasers.

Abstract: A laser cavity with passive switching by a saturable absorber and a laser incorporating the cavity. The laser cavity has a solid, active material saturable absorber, an entrance mirror and an exit mirror. The saturable absorber is a thin film of saturable absorber material directly deposited on the solid, active medium. The laser incorporates such cavity and a mechanism for pumping the cavity.

Abstract: A passively mode-locked laser and method for generating a coherent pseudo random pulse train is disclosed. The laser comprises an optical resonant cavity that is capable of sustaining the oscillation of a plurality of resonant modes having respective phases. A saturable absorber is positioned in the resonant cavity and has an optical intensity threshold beyond which multiple mode-locked pulses with random starting times are generated in the resonant cavity and periodically emitted by the laser. A pump injects power into the resonant cavity at a level at which the optical intensity that is incident on the saturable absorber exceeds the optical intensity threshold.

Abstract: An ultracompact array of microlasers in which Q-switching is performed by intracavity electroabsorptive modulators, to provide an array of relatively high-power beams with good beam quality and other beam characteristics. The microlasers are optically pumped by light beams from an array of semiconductor diode lasers, each of which is individually controlled by a separate electrode. Light from the diode lasers is coupled directly into a slab of solid-state crystal material, such as Nd:YVO.sub.4 (neodymium:yttrium vanadate), in which laser action takes place. The solid state material in part defines an array of laser cavities and an array of individually controllable Q-switching elements is integrated into the cavities, permitting Q-switching of each of the array elements. The Q-switching elements are electroabsorptive modulators that permit extremely rapid switching of the microlaser elements and provide output pulses of relatively high peak powers.

Abstract: A laser system and processing method exploits the absorption contrast between the materials from which a link (12) and an underlying substrate (22) are made to effectively remove the link from the substrate. Laser output in a wavelength range of 1.2 to 3 .mu.m (30) optimizes the absorption contrast between many materials (e.g., metals, polysilicon, polycides, or disilicides) and integrated circuit substrates (e.g., silicon, gallium arsenide, or other semiconductors) and permits the use of laser output in a wider range of energy or power levels, pulse widths, and spot sizes without risking damage to the substrates or adjacent circuit structures. Existing link processing laser systems can be readily modified to operate in the 1.2 to 3 .mu.m range.