Abstract: A tunable, solid state laser device with both visible and infrared laser emission is developed with a trivalent ytterbium-doped yttrium calcium oxyborate crystal as the host crystal. The Yb:YCOB crystal generates an infrared fundamental light over a wide bandwidth, from approximately 980 nanometers (nm) to approximately 1100 nm. The bandwidth generated by the Yb:YCOB crystal is approximately 100 nm wide and supports the generation of pulsed infrared light or when self-frequency doubled provides a compact, efficient, source of tunable, visible, blue or green laser light in wavelengths of approximately 490 nm to approximately 550 nm.

Abstract: The present invention relates to apparatus for providing orthogonally polarized light beams for use in precision metrology applications such as in the measurement of length or length changes using interferometric techniques. An input beam is introduced to a multifaceted anisotropic optically active acousto-optical crystal for travel through an interactive region where it experiences two acoustic beams that diffract it via small angle Bragg diffraction to form two orthogonally polarized internal beam components that are separated by a small angle of divergence and subsequently become external beam components available outside of the acousto-optical crystal for use in anticipated downstream applications. The acousto-optical crystal preferably is a uniaxial crystal comprising TeO.sub.2.

Abstract: A laser to produce pulses of light having predetermined spectral shapes, comprising a waveguide, an optical pump source, a gain medium to produce seed radiation, and a modulator and an array of Bragg gratings to modify the properties of the seed radiation. Once generated by the gain medium, the seed radiation propagates in the waveguide where it is first pulsed by the modulator. The resulting pulses are then selectively reflected by the Bragg gratings, which separates different spectral components of the reflected beam. This reflected beam then travels back to the modulator, which is timed to let only the desired spectral components go through. In this manner the laser is self-seeded and allows spectrum and wavelength selection from pulse to pulse.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for producing three-dimensional objects by selectively subjecting a liquid or other fluid-like material to a beam of prescribed stimulation. In a preferred embodiment a source of prescribed stimulation is controlled to reduce or inhibit the production of the prescribed stimulation during at least some periods when the prescribed stimulation is not needed to expose the material. In another preferred embodiment, the source of stimulation is controlled to vary the quantity of prescribed stimulation that is produced and allowed to reach the material. In an additional preferred embodiment, control of laser output occurs based on a combination of supplying a regulated amount of voltage to an AOM in conjunction with temporary sensing of laser power and a known desired power to attain.

Abstract: A programmable acoustooptic device including an elastooptic medium configured to receive an input optical pulse and an acoustic wave; an acoustic transducer configured to generate the acoustic wave in the elastooptic medium along a defined direction; and a programmable circuit coupled to the acoustic transducer and configured to program at least one of a frequency modulation and phase modulation of the acoustic wave, whereby the acoustic transducer generates a modulated acoustic wave, wherein an output optical pulse is generated and is a convolution of the input optical pulse with the modulated acoustic signal.

Abstract: An electroluminescent solid state device includes an active body member that is formed of a single crystalline metal oxide, such as aluminum oxide, that is doped with a rare earth element, such as erbium and/or terbium and an activator atom such as oxygen and/or fluorine. The metal oxide body member is electron excited by kinetic electrons that are emitted by a cold cathode. The ends of the metal oxide body member are polished to form a Fabry-Perot resonator, thus providing for coherent radiation from the device. As an alternative to the use of a Fabry-Perot cavity, an acoustic wave generator is associated with the metal oxide body member in order to launch acoustic waves into the body member. The frequency of energization of the acoustic wave generator operates to select a radiation wavelength from one or more emission wavelengths that are produced by doping the metal oxide body member with one or more rare earth elements.

Abstract: A digital circuit for counting the number of zeroes or ones in a data word comprising a plurality of series paths leading to one-hot encoded outputs. Each one-hot encoded output indicates a different number of like signals in the input data word. One of the plurality of series paths is activated by connecting the series path from an input power rail to the one-hot output. A series path is connected through a plurality of transfer gates, each controlled by either a single bit of the input data word or its complement. The series paths may be optimized to share transfer gates by interconnecting them in a tree or lattice structure. Subsections of the input data word may be counted separately in independent tree or lattice structures, then combined in subsequent combinational stages of the circuit. The resulting one-hot encoded count of like signals may then be binary encoded by a final stage of the counting circuit.

Abstract: A two-step, diode-pumped solid-state laser is disclosed. A diode laser source pumps a first solid-state laser. The first solid-state laser in-turns pumps a second solid-state laser. The second solid-state laser contains all the parameters suitable for efficient deep UV generation. A direct application of the diode-pumped solid-state cascade laser is for deep UV generation for photo-refractive surgeries.

Abstract: Electro-optical devices comprising a multifaceted anisotropic acousto-optical crystal for transforming a single-frequency beam comprising two individual linearly-orthogonally, polarized input beams into an output beam having two linearly-orthogonally, polarized principal output beams having frequencies that differ from each other and the input beam where the input beam preferably is a laser of frequency, f.sub.L. While the directions of propagation of the individual input beams are preferably parallel, and the directions of propagation of the principal output beams are preferably parallel, they need not be and instead the individual input beams and the principal output beams may beneficially have their own predetermined angle of divergence or convergence, respectively.

Abstract: An object of the present invention is to provide a wavelength selectable laser oscillator in wavelength tunable laser by which the rate of repetitive pulse oscillation of laser beam in a laser resonator can be markedly increased in comparison with that of conventional ones, besides excitation input can be decreased, and in addition, speed-up of wavelength tuning speed can be achieved, whereby flexibility is remarkably elevated in case of practicing the wavelength selectable laser oscillator.

Abstract: A master radio-frequency signal output from a master oscillator is input to a frequency converter. The frequency converter generates and outputs a multiplied signal having a frequency higher than that of the master radio-frequency signal by using the master radio-frequency signal. A loss of light reciprocating in an optic resonator of a laser oscillator is controlled by both the master radio-frequency signal output from the master oscillator and the multiplied signal output from the frequency converter. It is possible to highly precisely synchronize a pulse laser beam and a radio-frequency signal.

Abstract: An object of the present invention is to provide a wavelength selectable laser oscillator in wavelength tunable laser by which high-speed tuning of wavelength can be achieved while utilizing continuous-wave laser beam as the excited laser beam.

Abstract: Electro-optical devices for transforming a single-frequency, linearly polarized input beam from a light source introduced into a multifaceted anisotropic acousto-optical crystal into an output beam having two orthogonally polarized, output beam components that differ in frequency from each other and may be parallel or have a predetermined angle of divergence between them. The energy flux profiles of the output beam components may be spatially separated, partially coextensive, or substantially coextensive in accordance with the birefringence, acoustical, and optical properties of the acousto-optical crystal and/or the use of external elements for particular device embodiments.

Abstract: An electro-optical apparatus transforms a single frequency, linearly polarized laser input beam (18) from a light source (10) into an output beam (36) having two collinear orthogonally polarized output beam components (32,33) differing in frequency from each other by the frequency of a stabilized electrical signal (40) provided from an electronic oscillator (38). The output of the oscillator (38) is provided to a power amplifier (42) which is used to drive a piezoelectric transducer (46) affixed to an acousto-optical Bragg cell (52) through which the input beam (18) passes and is transformed into the output beam (36) composed of two beam components (32,33). The electrical output (44) of the power amplifier (42) is adjusted so that each of the output beam components (32,33) has approximately a preselected fraction of the intensity of the input beam (18).

Abstract: An object of the present invention is to electrically tune and control an oscillating wavelength of a laser at high rate having a good reproducibility without providing any mechanically movable section in the laser resonator. To achieve the object, a laser oscillator is provided comprising a laser resonator composed of a mirror on the output side and a total reflection mirror, a Ti:Al.sub.2 O.sub.3 laser crystal disposed in the laser resonator, an acousto-optic crystal disposed in the laser resonator and to which are inputted the outputting light rays from the Ti:Al.sub.2 O.sub.3 laser crystal, a piezoelectric element mounted on the acousto-optic crystal to input acoustic waves thereto, and a diffraction light ray correcting prism disposed in the laser resonator and for correcting an angle of deflection of the diffraction light rays outputted from the acousto-optic crystal.

Abstract: The wavelength tunable mode-locking optical fiber laser comprises non-linear amplifying loop mirror part having a light pumping lase diode, a gain medium doped optical fiber having the gain medium for oscillating the rambling light wave sequentially, a dispersion shifted optical fiber, and first polarization controller for making the continuous oscillation light wave to be maximized by adjusting the polarization of said propagating light. All elements of the non-linear amplifying loop mirror part are combined to each other in loop type on the above clock direction.

Abstract: A high average power, high brightness solid state laser system. We first produce a seed laser beam with a short pulse duration. A laser amplifier amplifies the seed beam to produce an amplified pulse laser beam which is tightly 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 may be steered rapidly to simulate a larger spot size. Alternately, a kHz system with several (for example, seven) beams (from amplifiers arranged in parallel) can each be focused to 20 .mu.m and clustered to create effective spot sizes of 100 to 200 .mu.m. These beams are useful in producing X-ray sources for lithography.

Abstract: An intracavity modulated pulsed laser and methods of using the same. In one preferred form, an intracavity modulated pulsed laser comprises an amplification medium, a pulsed pumping source, a beam modulator, and two mirrors, one totally reflective and one partially reflective for generating at least one laser output burst comprising a plurality of sub-pulses having variably controllable peak powers. In another preferred form, a non-linear crystal is utilized to double the frequency of each laser output burst. In still another preferred form, a fluorescence feedback control circuit is utilized to control the beam modulator.

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: In order to eliminate a mechanically movable section, such as a rotation mechanism of a diffraction grating, to achieve a compact fabrication of the whole apparatus, and to realize stable action for selecting a wavelength, a laser oscillator selecting a wavelength in a wavelength-tunable laser is composed of a laser resonator consisting of a mirror on the input side and a mirror on the output side; a laser medium which is placed in the laser resonator and can oscillate in a predetermined range of wavelengths; a crystal to which is piezoelectric element is attached, the crystal receiving acoustic waves from the piezoelectric element in accordance with a desired wavelength; and a polarizing plate which is placed in the laser resonator and transmits only the output light beam having a prescribed plane of polarization or having a prescribed direction of light propagation among the output light beams from the laser medium. The apparatus thereby outputs only the desired wavelength.

Abstract: A tunable laser that includes a laser amplifier and an acousto-optic filter (AOTF). The AOTF includes a waveguide having first and second ports. A first polarization filter passes light of a first polarization state, the first polarization filter being located between the laser amplifier and the first port of the AOTF. The laser also includes a first asymmetrical polarization rotator located between the first port of the AOTF and the first polarization filter. The first asymmetrical polarization rotator rotates the polarization of light traveling from the first port of the AOTF to the first polarization filter by 90.degree. while leaving unchanged the polarization of light traveling from the first polarization filter to the first port of the AOTF. A mirror reflects light leaving the second port of the AOTF back into the second port of the AOTF.

Abstract: A method and apparatus for controlling the form and timing of pulses emitted by a high-power solid-state laser, without the need for complex feedback circuits. The width and peak intensity of relaxation pulses emitted by the laser are controlled by use of an acousto-optic modulator (14) installed in the laser cavity, to lock the relaxation pulses to the frequency of radio-frequency (rf) control signals applied to the modulator. The number and average rate at which the pulses are emitted from the laser are independently controlled by varying the duty cycle of diodes (20) used to pump solid-state amplifiers (18) installed in the laser cavity. Short pump pulses can be selected to deliver only a few relaxation pulses from the laser, or longer pump pulses can be selected to deliver large numbers of relaxation pulses during each pump pulse.

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 high power diode pumped, acousto-optically Q-switched Nd:YVO.sub.4 laser includes at least one resonator mirror and an output coupler defining a resonator cavity. At least one acousto-optic Q-switch device and at least one laser crystal, with strong thermal focussing properties, are positioned in the resonator. One or more diode pump sources supply a pump beam to the laser crystal or crystals to generate an output beam. A power source supplies power to the diode pump source.

Abstract: An intracavity modulated pulsed laser and methods of using the same. In one preferred form, an intracavity modulated pulsed laser comprises an amplification medium, a pulsed pumping source, a beam modulator, and two mirrors, one totally reflective and one partially reflective for generating at least one laser output burst comprising a plurality of sub-pulses having variably controllable peak powers. In another preferred form, a non-linear crystal is utilized to double the frequency of each laser output burst. In still another preferred form, a fluorescence feedback control circuit is utilized to control the beam modulator.

Abstract: A room temperature solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG host material doped with a concentration of about 0.35% Ho ions, about 5.57% Tm ions and at least about 1.01% Cr ions. A broadband energizing source such as a flashlamp is disposed transversely to the laser crystal to energize the Ho ions, Tm ions and Cr ions.

Abstract: This invention is an optical device for laser sources, particularly for injection-seeded laser sources. The invention is an acousto-optic element used within a laser cavity to satisfy three functions--injection-seeding, frequency-shifting, and Q-switching. Use of this device rather than separate devices for each function increases reliability and lowers cost, while providing a large injection-signal into the laser cavity.

Abstract: An optical modulator device comprised of a semiconductor laser acoustically coupled to a thin film resonator is disclosed herein. The thin film resonator includes a piezoelectric crystal layer having first and second opposing surfaces, with the first opposing surface being in contact with a metallic electrode. The semiconductor laser is interposed between an acoustically reflective surface and the second surface of the thin film resonator. In a preferred implementation the acoustically reflective surface is defined by a submount underlying a substrate upon which is mounted the semiconductor laser.A frequency modulator exhibiting an improved modulation index may be achieved by integrating a superlattice structure within the active region of the semiconductor laser.

Abstract: An acousto-optic tunable filter ("AOTF") with a pair of electrodes on opposite sides of the waveguide. A voltage source applies a potential across the electrodes, thereby creating an electric field through the waveguide. The electric field controls an optical property of the waveguide by altering the birefringence of the waveguide. Suitably adjusting the potential applied by the voltage source results in suppression of sidelobes, correction of asymmetric sidelobes, and compensation for physical variations in the waveguide. The AOTF can be tuned very rapidly by a tuning voltage applied to the electrodes. In combination with a thermistor, the control voltage can compensate for changes in temperature. A spatially-varying electric field is generated by using a set of electrodes at different potentials, or by using a resistive element as an electrode, or by shaping the electrodes according to the desired field. A rapidly-varying control voltage can modulate a light beam in the filter.

Abstract: Deleterious feedback reflections from a power amplifier into a laser master oscillator are eliminated by interposing a nonreciprocal frequency shifter between the oscillator and amplifier, which shifts the laser frequency by more than twice the bandwidth of the laser oscillator resonant cavity.

Abstract: The invention relates to modelocked lasers including highly dispersive optical elements. The dispersive optical elements increase the oscillation pulse width inside the laser oscillators, which reduces the nonlinearity of the laser cavity for a given oscillating pulse energy. Compared to conventionally designed modelocked lasers, an increase in output pulse energy by one to three orders is achieved. As way of example, the technique is applied to an erbium fiber laser, where a chirped fiber Bragg grating is employed as the dispersive element. By using a Kerr-modelocking technique, a high nonlinearity may be sustained inside the fiber laser cavity, which leads to the generation of pulses with psec widths and energies up to 2 nJ. The large bandwidth of the chirped fiber Bragg grating allows a wavelength tuning range in excess of 10 nm, which is achieved by polarization control and a control of the gain spectrum of the laser.

Abstract: A high average power, high brightness solid state laser system. A laser produces a first pulse laser beam with a high pulse frequency. A pulse spacing selector removes from the first pulse laser beam more than 80 percent of the pulses to produce a second pulse laser beam having a series of periodically spaced short pulses in excess of 1,000 pulses per second. A laser amplifier amplifies the second pulse train 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. A preferred embodiment produces 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.

Abstract: A polychromatic or white light laser arrangement for changing the dimensions of the pumped portions of the active medium is realized by employing an optical divider for dividing the pump radiation into at least two beamlets, and one or more lenses for focusing the pump radiation onto the active medium. In one preferred embodiment, the optical divider includes a system of mirrors and lenses, or an acousto-optic deflector.

Abstract: An apparatus for preparing a medium for use in a printing process supports the medium (2) for rotation about an axis. A head (6) is mounted for movement parallel to the axis and includes means to direct a laser beam onto the surface of the medium. The laser beam engraves or exposes the series of cell sites (c) around the medium and an acousto-optic modulator (12) positioned in the path of the laser beam deflects the beam substantially in the direction of rotation of the medium (2). In a preferred example the beam tracks the surface of the medium at a speed matched to that of the medium so as to keep the beam stationary on the cell site while that site is being engraved or exposed. The beam may also be deflected to skip backwards or forwards over immediately adjacent cell sites.

Abstract: An intracavity modulated pulsed laser comprising an amplification medium, a pulsed pumping source, a beam modulator, and two mirrors, one totally reflective and one partially reflective for generating at least one laser output burst comprising a plurality of sub-pulses having variably controllable peak powers.

Abstract: Process for the production of an acoustooptical cell for a switched laser, the cell obtained, process for the production of microchip lasers having acoustooptical switching means and the microchip lasers obtained. A wafer is etched in order to bring about the appearance of a particular cristallographic plane (40) and on said plane are deposited piezoelectric means (86) able to create an acoustic wave. This wave makes it possible to switch the laser.

Abstract: Method and arrangement for locking a laser to an external cavity that is electronically tunable to provide an optical source that is highly coherent and which is frequency stabilized over a variable frequency range. Preferably, an injection laser is tightly coupled to an external acousto-optic cavity having a reflective mirror on its back facet and carried on an electro-optic crystal substrate. A transducer is coupled to the external cavity and converts an electrical sinusoidal input signal into an acoustic wave which travels along the electro-optic crystal substrate to modulate the refractive index of the material along the optical waveguide. The periodicity of the refractive index along the waveguide is accordingly determined to be equal to one half wavelength of the acoustic frequency propagating in the waveguide which locks the laser at a particular optical frequency determined by the refractive index profile. The arrangement is particularly desirable for frequency division multiplexing applications.

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 laser source which operated under the principals of cooperative unconversion produces controllable optical pulses at wavelengths which are shorter than the wavelength of the laser energy which pumps the gain medium. The source is a solid-state laser which employs a five percent Er:LiYF.sub.4 crystal which is arranged in an astigmatically-compensated 3-mirror cavity. Pumping is achieved at 1.5 microns in the infrared, and the system operates in a continuous-wave, mode-locked fashion in the green spectral region at approximately 544 nm. The cooperative inversion mechanism involves energy pooling by trios of excited rare earth dopant ions in the laser medium. Q-switching is achieved with the use of intracavity amplitude modulation so as to achieve three-fold upconversion. A 3-mirror astigmatically-compensated cavity with the gain medium permits modulation of losses in a manner which cannot be achieved with known systems and achieves high stability.

Abstract: An acousto-optical laser modulator includes an X-cut crystal quartz block. A transducer, such as a piezoelectric device, is coupled to the block. An electrical signal provided to the transducer causes the transducer to vibrate. The vibrations propagate through the block as acoustic waves. A laser beam incident on the block may be refracted or diffracted by the acoustic waves. X-cut crystal quartz has various properties such as high thermal conductivity, low acoustic attenuation, high loss modulation efficiency, high drive power efficiency, and low angular sensitivity which make it well suited for applications in acousto-optical devices.

Abstract: There is disclosed a harmonic light source which comprises: a laser light source for radiating a pumping laser beam; a laser active medium for performing a laser oscillation by receiving the laser beam from said laser light source, a resonator being formed between a reflecting surface and said laser active medium; and a harmonic generating medium provided in said resonator for generating a harmonic, and which serves to modulate the harmonic by applying a supersonic wave to one of said laser active medium and said harmonic generating medium.

Abstract: An electrically tunable optical oscillator. An acoustooptically tunable filter is located in a feedback path of an optical oscillator. The filter non-collinearly diffracts the light signal to selectively tune the oscillator. In one embodiment the light signal passes twice through a single filter in a single transit around the feedback path. In another embodiment the light passes through a pair of filters which are arranged such that any frequency shift created by one is cancelled by the other.

Abstract: A laser system is provided with a multi-function intra-resonator loss modulator to generate laser output having selectable amplitude within a relatively wide amplitude range and selectable duration within a relatively wide duration range while preserving mode quality, waist position, and divergence of the laser output.

Abstract: A Q-switched solid state laser provided with a laser medium, a pump source for generating pumping light used to pump the laser medium, a pair of laser resonance mirrors respectively placed at both sides of the laser medium and a Q-switching acousto-optical element intervening between the pair of laser resonance mirrors for controlling Q-switching oscillation by abruptly changing a loss of resonant laser light passing therethrough. Further, the Q-switching acousto-optical element satisfies a predetermined condition .vertline.Ms.vertline..gtoreq.1.times.10.sup.-12 S.sup.3 /g..degree.C. where Ms denotes a parameter defined as Ms=M/(ds/dt) by letting (ds/dt) designate a thermal change in optical path of the Q-switching acousto-optical element and also letting M represent a performance index of an acousto-optical material of the acousto-optical element. Thereby, the Q-switched solid state laser excels in what is called a "beam pointing stability" and "pulse-to-pulse stability".

Abstract: The CAVITY REFERENCED ACOUSTO-OPTICAL LASER FREQUENCY STABILIZATION shown here locks the frequency of a laser 10 to that of a reference cavity 26. It frequency modulates the input 24 to the cavity 26 with an acouto-optical modulator 18 which operates on a sample 16 extracted from the output beam 14 of the laser 10 rather than on the output beam 14 itself. The cavity 26 can be tuned to any convenient frequency, and the operator is not limited to any specific reference absorption material. Since dithering is done on the sample 16 rather than on the output 14, no contamination of spectral purity takes place.

Abstract: A laser based accelerometer system uses small motion induced shifts in frequency to measure the motion of an object without contact thereof. This technique is particularly useful for determining the vibratory and velocity characteristics of objects that are otherwise inaccessible for direct motion measurement by contact sensors.

Abstract: A single frequency solid state laser has been designed for generation of a high power Q-switch pulse followed by a quasi-CW low power tail by properly controlling the laser resonator transmission via an intracavity Q-switch. The generation of a stable single frequency pulse is accomplished by a primary feedback control system containing a central timing and prelase control unit. Generation and smoothing control of a quasi-CW pulse tail is accomplished through a secondary feedback control system.

Abstract: A acousto-optic Fabry-Perot optical modulator (10) has a crystalline body (12) having a first partially reflective electrode (14) for receiving radiation, including laser radiation having a wavelength or wavelengths of interest, and a second, oppositely disposed partially reflective electrode (14) for emitting the received radiation including the laser radiation. The modulator is driven by an alternating source (16) at a resonant frequency of the crystalline body and intensity modulates at the resonant frequency only the emitted laser radiation. A detector (18) is positioned for receiving the emitted radiation, including the intensity modulated laser radiation, and has an output signal expressive of the intensity of the emitted radiation. Signal processing circuitry (20,34) is coupled to the detector output signal and is responsive thereto for identifying the intensity modulated laser radiation for indicating when laser radiation is received by the modulator.

Abstract: A miniaturized Q-switch is added to the resonant cavity of a compact laser diode pumped solid state laser to produce short high peak power pulses. Q-switching the compact diode pumped solid state lasers takes advantage of the relatively high gain and short cavity length to provide a desirable combination of pulsewidth and pulse energy. Nd:YAG or Nd:YLF are useful solid state laser materials for Q-switching, or other longer lifetime rare earth ions such as erbium or holmium for greater energy storage. The Q-switch is formed of a material such as TeO.sub.2, SF.sub.10, or LiNbO.sub.3 with an acoustooptic figure of merit substantially greater than fused silica. Pulsewidths of 10-50 ns are achieved at pulse energies of 10-20 microjoules. TEMOO output is easily produced by the compact laser pumped solid state resonator. Applications include materials processing, link blowing in semiconductor memories, marking and scribing, and optical time domain reflectometry.

Abstract: An improved dynamic moire interferometer comprised of a lasing medium providing a plurality of beams of coherent light, a multiple q-switch producing multiple trains of 100,000 or more pulses per second, a combining means collimating multiple trains of pulses into substantially a single train and directing beams to specimen gratings affixed to a test material, and a controller, triggering and sequencing the emission of the pulses with the occurrence and recording of a dynamic loading event.