Abstract: A method for selecting a semiconductor laser is provided which contributes to improved productivity of a highly reliable semiconductor laser of prolonged lifetime, and which includes the steps of: (a) measuring highest peak intensity, Ia, and next highest peak intensity, Ib, of an interference fringes pattern of laser radiation of each semiconductor laser using an interferometer to find a damping ratio of visibility of the interference fringes pattern, .gamma.=Ib/Ia; and (b) selecting a semiconductor exhibiting self-pulsation by selecting a semiconductor laser which emits laser radiation whose damping ratio of visibility, .gamma., is 0.5 or less.

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: Low power discharge preionizers, or species, are provided by a ionizable species generator that preconditions a laser gas to eliminate arcing in lasers, such as pulsed (high repetition rate) lasers. The present invention creates the species in a low power discharge and the species prevents initial arcs from occurring between high voltage electrodes of the laser. The laser comprises a pressure vessel containing the laser gas, a fan for circulating the laser gas, a heat exchanger, a catalyst, and two high voltage discharge electrodes for exciting the laser gas to create lasing. A high voltage power source is coupled to the electrodes for providing a discharge voltage thereto. A primary auxiliary discharge source is disposed adjacent to the electrodes that is used as a preionizer that creates a low density of charged particles in the main discharge volume to act as a uniform seed for the main voltage pulse derived from the electrodes.

Abstract: In a power controlling device for laser emitting apparatus, a laser diode and a photodiode are provided. Current is generated by the photodiode in accordance with the intensity of laser beam received. The current flows across a resistor to generate a voltage, which is compared with a reference voltage. There is further provided a circuit for generating the reference voltage, which includes a pulse signal generating circuit in which a duty cycle of the pulse signal is changeable, and a voltage generator which generates voltage in accordance with the duty cycle of the pulse signal. The laser diode is driven in accordance with the result of comparison of the voltage generated by the resistor with the reference voltage which is adjusted in accordance with the duty cycle of the pulse signal.

Abstract: Filtered regenerative feedback is used to modulate a laser or other source of electromagnetic radiation to generate optical pulses whose amplitudes and repetition rates are continuously tunable. The technique is in principle applicable to any source of electromagnetic radiation and is especially effective for semiconductor diode lasers.

Abstract: The present invention relates to the feedback control of the power output from a high-frequency generator for supplying a pulsed laser. During a pulsing operation, the power output is regulated by means of a controllable grid-leak resistor in the grid circuit of the valve tube of the high-frequency generator. An equivalent system is preselected for the feedback control in the pulse intervals and, consequently, transient reactions are minimized.

Abstract: An active night vision system capable of viewing a target over long distances utilizes laser illumination in eye-safe, invisible wavelength regions of about 1.52-1.76 .mu.m or about 2.03 .mu.m-2.34 .mu.m for illuminating a target; and electronically receives, intensifies and displays or stores the reflected image.

Abstract: A pulsed solid state laser system is disclosed which utilizes a plurality of individual laser rods which are sequentially pumped and whose beans are combined into a single interleaved output bean. The individual laser rods are pumped at an average power level which is below that for maximum output power from each rod, thereby obviating the need for refrigeration cooling. A compact optical system is disclosed which permits a constant beam size even at different pump levels and other advantages. A compact cooling system is also disclosed.

Abstract: Phase-locking means are provided for synchronizing the pulse timing of two (or more) passively mode-locked pulsed lasers. The phase-locking is carried out at a frequency much higher than that of the fundamental repetition rate of the lasers because it results in much higher sensitivity. The signal from the two bandpass filters is applied to a phase detector. A phase-locked loop circuit ("PLL") is employed to generate an error signal which is applied to a piezoelectric transducer ("PZT") attached to a mirror in one of the laser cavities. Corrections in the position of the mirror driven by the error signal help reduce the effects of phase noise in the relative fundamental repetition frequencies of the two lasers so that they are effectively synchronized with one another with a "jitter" of less than 1 ps.

Abstract: An amplitude stabilization circuit for a CO.sub.2 laser employing a filter for generating a Q-switched baseband video pulse representing intracavity laser flux, a comparator to detect when the video pulse and flux reach a selected level, and logic timing circuitry for timing generation of a Q-switch discharge pulse to occur at the peak of the intracavity flux. A second comparator is advantageously used to generate a sample signal for frequency locking from the baseband video pulse.

Abstract: An optical pulse generator for producing mode-locked optical pulses comprises: a beam splitter; first and second optical loops coupled together by the beam splitter so as to define a figure eight optical path in which a light beam propagating toward the beam splitter in one of the first and second optical loops is split by the beam splitter to form two light beams propagating in opposite directions around the other one of the first and second optical loops; a direction dependent loss element disposed in the first optical loop for reducing the intensity of light propagating in a predetermined direction around the first optical loop; a nonlinear element disposed in the second optical loop and having an intensity dependent nonlinear optical transmission characteristic; an optical gain medium disposed in a selected one of the first and second optical loops; coupling apparatus for coupling pump light into the selected one of said first and second optical loops having the gain medium, and for coupling mode-locked o

Abstract: A millimeter wave device. Pulses of electrons illuminate a diamond switch at rates of 1 billion to 100 billion pulses per second. The diamond switch connects a high voltage source to a millimeter wave transmitter or other load. In preferred embodiments the electron pulses are provided by a klystron or a traveling wave tube.

Abstract: A drive circuit for supplying a constant drive current to the anode terminal of a semiconductor light emitting device, includes a current supply source connected to the anode terminal for supplying a bias current to the semiconductor light emitting device. Since the drive circuit is formed so as to supply the bias current to the anode terminal of the semiconductor light emitting device, a charge current for charging a conjunction capacitance can be reduced independently on the time period of turning off the semiconductor light emitting device. As a result, a spike noise can be removed in the laser current waveform at its rise-up part, and a reduction of its rise-up speed can be restricted, both of which are due to a dependent upon the time period of turning off the semiconductor device.

Abstract: In order to obtain a weld bead having a good outer appearance with little splash of sputters or the like and a sufficient shearing force, there is provided a flash lamp control section for controlling flash lamps so as to generate two rectangular waves in a pulse wave form at every cycle of a pulse laser beam generated by a pulse YAG laser during the irradiation of the pulse laser beam on coated metal materials. The flash lamp control section is adapted to control a relationship between a peak power and a pulse width of a first rectangular wave and a peak power and a pulse width of a second rectangular wave in predetermined ranges. Under the control of the flash lamp control section, the pulse laser beam generated by the pulse YAG laser is irradiated to the coated metal materials thereby carry out the irradiating operation.

Abstract: An optical transmission system, especially useful in undersea applications, includes an optical path between two terminals with one or more repeaters located between the terminals for amplifying optical communications signals flowing in the optical path. The repeaters contain optical fiber amplifiers driven by pump lasers. The average optical power produced by the pump lasers is controlled in proportion to the magnitude of electrical line current produced by a controllable constant current source located in one of the terminals. This is achieved by regulator circuits which are responsive to a signal related to the magnitude of the line current and signals related to the actual optical output of the pump lasers. The magnitude of the line current may be conveniently set at the terminals so that the lowest bit error rate is achieved in the transmission system.

Abstract: A laser system (20) controlling laser pulse energy by feedback to the laser Q-switch (34) is disclosed. A feedback signal (40) is used to control the time duration of the high loss state of the Q-switch for automatically adjusting the output pulse energy to substantially equal an energy setpoint (84).

Abstract: A laser apparatus or system is provided including a driving mechanism for driving a pulsed semiconductor laser which injects optical energy into a lasing medium. A digital filter is employed to adjust the time duration or pulse width of drive pulses which excite the semiconductor laser. In this manner, the irradiation of the lasing medium is adjusted by pulse width modulation of the driving current in the semiconductor laser. The laser apparatus employs a sampled output, digitally filtered, negative feedback signal to drive the semiconductor laser. This structure has the effect of making the semiconductor laser responsive to changes in the laser system or to undesired degradation in the laser system. The laser apparatus compensates for the inherent time lag in laser output power energy during initial startup of the laser.

Abstract: A method and a device are provided for generating a multi-pulse laser beam including at least three laser beams, from a single pulse laser beam oscillated from a single laser beam source and a method and an apparatus using the pulse generator for laser beam machining with a two-wavelength multi-pulse laser beam suitable for fine-patterning a multi-layered circuit board formed of metal thin films and resin layers or ceramic bodies. One pulse laser beam from the laser beam source is separated into linear polarized laser beams in first and second directions by a polarization beam splitter, with the beam in the first direction being outputted as a first pulse beam of the multi-pulse beam. The beam in the second direction is incident to a combination of an optical fiber or a glass plate and a 1/4 wavelength plate, and is delayed and non-linearly polarized there to become a delayed and non-linearly polarized laser beam.

Abstract: An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90.degree. angle of incidence.

Abstract: A laser apparatus is provided in which a laser diode is driven with a plurality of drive pulses to generate a plurality of first laser pulses. Each first laser pulse occurs during a respective window and has a predetermined pulse width determined by a corresponding drive pulse. An electronic shutter which intercepts the laser beam is then opened in response to a trigger signal to permit a second laser pulse to be emitted from the laser rod during each window. The laser energy output of each of the second laser pulses from the laser rod is continuously monitored on a window by window basis to determine if the energy output of each of the second laser pulses exhibits a predetermined desired value. The energy output of the second laser pulse observed during each of the windows is then reported as a respective energy report signal set for each of the windows.

Abstract: A high-Q, gainless external resonant ring cavity for generating high peak power pulses from semiconductor laser diodes and other low-power, continuous-wave laser sources. The resonant ring cavity stores laser energy from a continuous-wave laser source and periodically dumps the stored laser energy in pulses having peak power levels many times greater than that of the laser source.

Abstract: A pulse compression and prepulse suppression apparatus (10) for time compressing the output of a laser (14). A pump pulse (46) is separated from a seed pulse (48) by a first polarized beam splitter (20) according to the orientation of a half wave plate (18). The seed pulse (48) is directed into an SBS oscillator (44) by two plane mirrors (22, 26) and a corner mirror (24), the corner mirror (24) being movable to adjust timing. The pump pulse (46) is directed into an SBS amplifier 34 wherein SBS occurs. The seed pulse (48), having been propagated from the SBS oscillator (44), is then directed through the SBS amplifier (34) wherein it sweeps the energy of the pump pulse (46) out of the SBS amplifier (34) and is simultaneously compressed, and the time compressed pump pulse (46) is emitted as a pulse output (52). A second polarized beam splitter (38) directs any undepleted pump pulse 58 away from the SBS oscillator (44).

Abstract: A wavelength monitor/stabilizer for narrowly controlling the bandwidth of laser; the monitor/stabilizer uses parameters Q, F or G derived by measuring diameters of interference fringes given by the beam of the wavelength-controlled narrow bandwidth laser e.g. excimer laser and those given by the reference light e.g. of a mercury lamp. The controlling is made by controlling the parameter to be in a predetermined range. An image sensing unit for detecting the interference fringes are splitted into plural image sensors with adjustable distance for enabling more rapid measurement by skipping the in-between part.

Abstract: A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations.

Abstract: Method and apparatus for stabilization of pulse energies produced by a continuously pumped, Q-switched, solid-state or gas laser, through control of the optical power delivered by an optical pump to the laser, in order to limit the energy emitted in any single laser pulse as a result of Q-switching. The laser pump is driven at full strength for a selected initial refresh time t.sub.r. If a Q-switch trigger signal is received by the laser before the elapsed time .DELTA.t has reached the refresh time t.sub.r, the laser emits a pulse with the reduced energy stored in the laser at that time. If the elapsed time reaches or exceeds the refresh time t.sub.r, the optical pump power subsequently delivered to the laser is reduced to a lower level, which may be time-dependent, that is sufficient to maintain the net energy stored in the laser at a predetermined value so that the energy in a subsequently emitted laser pulse does not exceed a selected limit.

Abstract: A light pulse generator is provided comprising, a first and a second semiconductor laser diodes, each having a highly reflective surface and a non-reflective surface arranged opposite to each other, an optical system arranged between the highly reflective surfaces of the first and the second semiconductor laser diodes with the two non-reflective surfaces being confronted by each other, and a current supply for feeding the first and the second semiconductor laser diodes with discrete high-frequency currents respectively. The high-frequency currents repeat at intervals of a period equal to n times (n being an integer) the duration of light traveling one cycle within the optical resonator and have a phase difference of .pi./n from each other. Accordingly, the light pulse generator can produce a series of short-width light pulses while minimizing the generation of unwanted sub pulses.

Abstract: A processless phototool generator uses a pulsed excimer laser to image a deformable mirror spatial light modulator onto a thin ablateable coating on a quartz substrate. The light pulse ablates and clears the coating from selected areas according to the data pattern in the deformable mirror array. Exposure uniformity is enhanced by a two dimensional overwriting method. The high image reduction ratio enables high power densities on the substrate without exceeding the permissible power density on the deformable mirror array. Since the recording is processless (i.e. no development required) the generated image can be verified immediately after writing. The last feature is of particular importance in phase-shift masks.

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

Abstract: An optical pulse generating apparatus having a semiconductor laser medium and an external resonator comprising an optical waveguide path. A reflecting element in the optical guide path is given such a reflection wavelength characteristic as to suppress other components than the component of an oscillation main longitudinal mode, so that the level of the main longitudinal mode component is raised and optical pulses with a narrower spectrum width and pulse width are produced.

Abstract: Currently laser diode pump redundancy for an optical fiber amplifier is obtained by selectively connecting one of two diode pumps to an optical amplifier via an optical switch. When the diode laser pump which is connected to the amplifier becomes defective, the optical switch is activated, either remotely or automatically, and the good laser diode is substituted for the defective laser diode pump. In another arrangement, two laser diodes are coupled to an optical fiber amplifier via a polarization-dependent optical coupler. In each instance, a second laser diode is required to provide pump redundancy for an optical fiber amplifier.In this invention, at least, two laser diodes are coupled via a 3 dB optical coupler to supply pump power to each of the two optical fiber amplifiers simultaneously. If one of the laser diode pumps fails, the other laser diode pump provides pump power to each of the optical fiber amplifiers.

Abstract: A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter.

Abstract: An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

Abstract: A laser output radiation with reduced energy noise components is produced which is also usable for the formation of short, stable laser pulses in the pico- and sub-picosecond ranges. The low noise components are obtained by superposition of the resonator wave in the active medium with its fed back output radiation lying on the order of magnitude of the spontaneous radiation emission of the oscillating resonator wave.

Abstract: Stabilized pulsed laser apparatus including pulsed laser means providing an output beam including a plurality of pulses, a pulse controller providing control instructions to the laser, and an attenuator for selectably performing attenuation of the output beam of the pulsed laser means in response to at least the time interval between a given pulse and the pulse preceding it, for maintaining at least one desired energy characteristic notwithstanding changes in at least the time interval.

Abstract: A low noise pulsed light source using a laser diode for generating a short pulsed light of a high repetitive frequency. The low noise pulsed light source includes a laser diode drived by an electric pulse generator for emitting repetitive pulsed light; a current source for supplying a bias current to the laser diode; and a photodetector for detecting the repetitive pulsed light emitted from the laser diode; and control means. The control means modulates at least one of the bias current from the current source and the amplitude of a pulse signal generated from the electric pulse generator in accordance with an output signal from the photodetector such that the intensity of the pulsed light is kept unchanged and any noise involved in the same is reduced.

Abstract: The invention, a method and circuit for controlling the evolution time interval of a laser output pulse, comprises means for pumping a laser medium 13 in a resonator 10 that includes a Q-switch 22 and polarizer 26 that act in combination to control the loss in the resonator 10. A photodiode 11 senses the resulting fluorescence 12 which is applied to a two level Q-switch driver 27 the output of which selectively adjusts the level of loss in the Q-switch 22 and polarizer 26 from high to intermediate to substantially zero loss states to control the evolution time interval of the resulting laser output pulse.

Abstract: The present invention is a laser system that includes an acousto-optic device (24B) having an optical medium (40B) that maintains a substantially uniform index of refraction even when subjected to nonuniform thermal or mechanical stress. The acousto-optic device provides substantially distortion-free polarized output light that can be directed accurately to strike an intended target.

Abstract: An antiresonant nonlinear mirror to replace one mirror of a laser for passive modelocking of the laser, the antiresonant nonlinear mirror comprising: a beam splitter for coupling the mirror to a laser cavity; a mirror arrangement for defining an optical ring with the beam splitter in which two light beams produced by the beam splitter in response to a light beam from the laser cavity can counterpropagate around the ring; an intensity dependent anisotropic nonlinear element disposed within the ring; and a polarization sensitive element disposed within the ring for adjusting the birefringence thereof to produce spontaneous modelocking in the coupled laser cavity.

Abstract: Disclosed is a laser source with beam scanning, of the type comprising: a pump laser source emitting a pump beam with a determined wavelength; a pressurized gas cell receiving the pump beam and emitting, by Raman effect, an output beam with a wavelength called a Stokes wavelength; a control light source transmitting a control beam to the gas cell, this control beam having a wavelength that is substantially equal to the Stokes wavelength; wherein said light source includes means for the spatial and/or temperal modification of the injection of the control photons of the control beam into said cell constituted by a multiple-laser strip structure, forming a power slave laser and cooperating with means for modifying the radiation pattern of said multiple-laser strip structure, so as to prompt the emission of the output beam in a variable direction.

Abstract: A fast rise time optical pulse generator is provided which utilizes a laser cavity having a gain medium with a pair of cavity arms extending therefrom, each cavity arm having a feedback element at its distal end. The gain medium has the property that if optical waves enter the gain medium from the two arms simultaneously, the gain is reduced. This will generally occur as a result of a gain saturation effect such as spatial hole burning. Since the gain reduction does not occur for pulses of a length equal to the length of the laser cavity or for odd submultiples of such pulses, outputs are obtained at one of these pulse lengths. Various means are provided for tuning the system to the desire harmonic.

Abstract: A pulsed laser system for visually detecting faults in optical waveguides. A laser operating at a duty cycle of less than fifty percent (50%) produces visible light pulses at a frequency sufficiently high as to visually appear to be continuous. The laser is coupled to an optical waveguide by a connector. Faults are located due to a visible glow at a defective point on the waveguide.

Abstract: In this invention an optical fiber doped with a rare earth element and coupled to be pumped with a laser is coupled to an optical feedback loop. The feedback loop couples the output signal of the fiber amplifier to the input of the fiber amplifier. A narrow bandwidth filter coupled to the feedback loop allows a selected wavelength of the amplified spontaneous emission to pass from the output of the fiber amplifier to the input of the fiber amplifier. The feedback signal has a wavelength which is different from that of the pump signal and the wavelengths of the signals to be amplified. In operation, when bursts of optical signals from at least two discrete word or frequency division multiplexed channels are amplified in the fiber amplifier, the undesired fluctuations of gain of the output signals normally due to transient saturation of the erbium-doped filter amplifier are substantially eliminated.

Abstract: A laser structure utilizes air cooling and RF induction excitation of a gaseous active medium. A means for exciting the active medium is provided including a switching power supply utilizing pulse width modulated switching to provide an RF energy output. The RF output is coupled to a tank circuit which comprises a capacitor, an inductor, and at least one coupling structure. A means for generating a magnetic field-along the axial length of the laser bore is provided and can comprise either permanent magnets or a DC source coupled to the coupling structure. The laser further includes means for dissipating heat from the laser bore by utilizing the coupling structures as convective cooling fins with forced air circulated thereabout.

Abstract: An improved nitrogen laser includes two oppositely disposed discharge electrodes contained within a resonant chamber that is supplied with a mixture of nitrogen gas and a substantially small amount of electronegative gas. The mixture used within the chamber makes it possible to operate the nitrogen laser at a high voltage output and a higher frequency rate.

Abstract: A bistable semiconductor laser device has reset light irradiation means for irradiating a reset light for stopping the delivery of a lasing light from the laser. The laser comprises an active layer comprising a gain region in which stimulated emission occurs to attain a optical gain and a saturable absorption region in which no optical gain is attained at the lasing wavelength, resetting of the laser being carried out by irradiating onto the gain region of the laser a light having a wavelength in accordance with which the irradiated light is amplified by stimulated emission thereby to reduce carriers in the gain region of the laser.

Abstract: In an optical communication system, in order to reduce simultaneously both second and third harmonic distortion in a light beam from a modulated semiconductor laser, a nonlinear interferometric deivce--such as a Fabry-Perot etalon--is inserted in the path of the beam. The parameters of the interferometric device--such as its phase and finesse--are selected such that, for a suitable laser bias current, the second and third harmonics produced by nonlinearities of the laser (plus nonlinearities of the transmission medium such as an optical fiber, if any, through which the beam propagates from source to receiver) are significantly compensated by nonlinearities of the interometric device.

Abstract: A high power fast switch for generating pulses of current to a load from a high voltage power source. A laser beam illuminates a cathode which simulates the emission of pulses of electrons which illuminate a diamond target. The pulses of electrons cause the diamond target to become conductive permitting high power pulses of electric current to pass through the diamond target from a high voltage source to a load. In a preferred embodiment a Klystron buncher compresses the electron pulses onto the diamond target.

Abstract: The invention is a method and circuit for shaping laser pulses 17' in which a laser medium 12' in a laser resonator 10' that includes a Q-switch 14' and polarizer 13' which act in combination to control the loss of the resonator 10' and provide the laser output 17' representative of such loss. An optical diode 22' senses the level of the output pulse 17' and provides an output signal 23' that when amplified is used with a control voltage from a supply 29' provide a control signal 19' which is applied to Q-switch 14' to control the shape of the output pulse 17' by adjusting its length.

Abstract: A low-power, continuous wave laser beam is injected into the optical cavity of a high gain, high power, short pulsed laser. The output beam features excellent power and wavelength stability.

Abstract: Laser apparatus is disclosed which comprises a compact pulsed dye laser for high pulse repetition frequency operation. The pulsed dye laser includes a resonator cell having a passageway through which dye solution is circulated and a pump laser for optically pumping the resonator. In order to provide laser apparatus which is capable of very high performance, the dye solution is circulated through a narrow passageway at high flow rate and the pump laser is operated at a high pulse repetition frequency.