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 object of the present invention is to provide an optical device which has obliterated, by the use of a nonlinear optical crystal, the need for a complicated adjustment operation of positions as seen in an optical device used for obtaining an output light having a frequency different from an input light. To be specific, Q switching electrodes 12A, 12B, phase adjustment electrodes 9A, 9B and periodic domain inversion part 15 are disposed in desired parts of path 2 in an optical crystal 1 having nonlinear optical character, electro-optical character and laser activity. By the action of an input light P0 supplied from an input side 3, oscillation light P1 is oscillated, harmonic is generated by nonlinear optical character and periodic domain inversion part 15, or output light P2 having a frequency different from that of input light P0 is emitted from output side 4 by optical parametric oscillation.

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: The light emitted by a laser diode 1 is entered into a beam splitter 5, and its reflected light is given to an optical band pass filter 8. The light passing through the optical band pass filter 8 is received by a photo diode PD1.The light once reflected by the optical band filter 8 and passing through the beam splitter 5 is received by a photo diode PD2. The reception ratio of the photo diodes PD1, PD2 is calculated in output ratio calculator 9. By controlling the emission wavelength of the laser diode 1 so that its ratio may be constant, laser light of high precision and stable wavelength is emitted.

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: In a laser processing machine, a laser control system includes a photo detector (21) detecting intensity of light generated by laser-induced plasma produced by applying laser beams on an object, and a control unit (30) for controlling a laser pulse signal to have an optimum pulse width and optimum pulse period effective in each pulse signal based on the detection signal, so that the optimized laser pulse signal is obtained to thereby automatically control the generation of the laser beams, where the pulse width of each pulse is controlled by the control unit (30) so that the detection signal outputted from the photo detector (21) has its peak values to be all equal to a constant level (Vp), and the pulse period of each laser pulse signal is so controlled as to have a reference threshold level (Vr) which is previously given by the material of the object, and thus the total processing time in perforating process can be remarkably reduced.

Abstract: A laser apparatus includes a laser resonator having a first reflective surface and a second reflective surface, the laser resonator further including a laser medium disposed between the first reflective surface and the second reflective surface for processing light reflected from the first and second reflective surfaces to output a laser beam to be resonated, and a resonator loss varying unit disposed between the first reflective surface and the second reflective surface of the laser resonator, the resonator loss varying unit being capable of switching a state thereof between a first state having a resonance frequency substantially coinciding with one of frequencies at which laser oscillation of the laser resonator is possible and a second state having the resonance frequency shifted to the value that is substantially different from any one of the frequencies at which laser oscillation of the laser resonator is possible to vary a loss of the laser resonator.

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: The bias point of an electro-optic modulator, such as an Mach-Zender modulator, is automatically controlled. A pilot signal, preferably two pilot tones at different frequencies, is applied to the modulator. The output of the modulator then contains various components resulting from the pilot signal. An error signal is generated, preferably coherently, based on one of these components, termed the pilot component, which preferably is located at the difference frequency of the two pilot tones. A bias signal which controls the bias point of the modulator is adjusted based on the error signal. The coherent generation of the error signal facilitates feedback loops based on phase and/or amplitude control and also supports locking the electro-optic modulator to a bias point with a preselected slope (either negatively or positively sloping).

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: A laser beam generating device which, by addition of a simplified structure, can enlarge the spectral width of the laser light and lower the coherence to a moderate value. The laser light generating device includes a first laser light source 31, a second laser light source 32, phase modulation units 34, 35 for phase-modulating the beams from the light sources with a sole frequency component or plural frequency components, and an additive frequency generating unit 33 for producing a light beam of the shorter wavelength based on the wavelength of the light phase-modulated by the phase modulation units 34, 30. The fundamental wavelength laser light generated by the first laser light source 31 is phase-modulated by the phase modulation unit 34 based on a pre-set modulation amplitude and the modulation frequency so as to be enlarged in spectral width before being incident on the additive frequency generating unit 33.

Abstract: A laser apparatus capable of emitting a laser beam upon wavelength conversion and intensity modulation, which comprises a fundamental wave resonance means comprising a light emitting part, an optical resonator comprising mirrors sandwiching the light emitting part and capable of laser resonating, and a modulation-conversion means set inside said optical resonator, said light emitting part being a semiconductor light emitting element or a laser medium, said modulation-conversion means converting, by a nonlinear optical effect, a fundamental laser resonance wavelength light, and phase modulating said light by an electro-optical effect, and a modulation part of said modulation-conversion means comprising electrodes for application of a modulation voltage.

Abstract: A wavelength system for measuring and controlling the wavelength of a narrowband laser. The system includes a wavemeter for measuring incremental changes in wavelength and an atomic wavelength reference for calibrating the wavemeter. The atomic wavelength reference includes a vapor cell for providing a vapor having at least one absorption line near a desired operating wavelength. The system includes a wavelength tuning device with a tuning range sufficient to tune the laser to operate at the wavelength of the absorption line in order to calibrate the wavemeter.In a preferred embodiment, the laser is an ArF laser, and the vapor is platinum and the absorption line is either 193,224.3 pm or 193,436.9. Improvements over prior art devices include an improved etalon having a support flange to provide a low stress three-point hanging support for the etalon without use of elastomers.

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: 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: Opto-electronic oscillators having at least one Brillouin feedback loop based on the Brillouin selective sideband amplification to provide a sufficient gain for the oscillator to start and sustain an electro-optic oscillation. Such an oscillator can generate high frequency, high spectral purity, and tunable microwave signals in both optical and electrical domains.

Abstract: The invention relates to a microlaser cavity switched with the aid of an electrooptical material (54). Electrodes (84, 86) are produced on support elements (80, 82) and the latter are then applied on either side of the electrooptical element. Solid electrodes can also be applied on either side of the electrooptical material.

Abstract: A Q-switch laser apparatus includes a laser cavity formed with a pair of reflective surfaces having a laser medium mounted therebetween and a power supply operatively connected to the laser cavity to pump the laser medium. An electro-optic Q-switch is mounted in the laser cavity in a saturable absorber of less than 100% saturable transmittance is located in the laser cavity between the laser medium and the electro-optic Q-switch for suppressing prelasing in the laser. The saturable absorber may be a Cr4+:YAG used with an electro-optic Q-switch of LiNbO.sub.3. The method includes selecting the laser apparatus and selecting a saturable absorber of less than 100% saturable transmittance and attaching the selected saturable absorber in the laser cavity between the laser medium and the electro-optic Q-switch for suppressing prelasing therein.

Abstract: The invention relates to a laser cavity having an active laser medium and two mirrors forming a Fabry-Perot cavity, characterized in that the cavity is at the optical stability limit and in that there are means for varying the optical length of the cavity, so as to pass from an optically unstable state into a stable state.

Abstract: A resonator (1) for electromagnetic waves with a stabilizer can, for example, be part of a mode-coupled fiber laser. The stabilizer (2) is provided to stabilize the effective length of the resonator (1). Stabilization is accomplished in a first embodiment via two temperature controllers (3, 4) controlling the temperature of a first portion (L1) and the temperature of a second portion (L2) of the resonator (1). The temperature of the second portion (L2) is controlled as a function of an error signal generated by deviations of the resonator (1) from a nominal length. The second portion (L2) is significantly shorter than the first portion (L1).

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: A microlaser cavity to a microlaser incorporating an active solid medium (38) and means (44) for switching the cavity, whilst also having, within said cavity, at least one element (46) of an optically nonlinear material, making it possible to multiply the basic frequency of the laser cavity by a factor n (n.gtoreq.2).

Abstract: A high power laser source having a preselected broad bandwidth, including a master oscillator providing a single-mode laser beam, a resonant electro-optical modulator and a source of radio-frequency (rf) modulation voltage, to produce a modulator output beam having sidebands spaced on each side of the nominal frequency of the single-mode laser beam. The bandwidth and the number of modes may be varied by controlling the voltage applied to the modulator. At least one additional modulator in series with the first provides for the addition of other sidebands overlaying those generated with just one modulator. In another embodiment of the invention, the modulator is installed in a PC MOPA (phase conjugated master oscillator power amplifier) configuration to provide modulation only on the return path of the beam from a phase conjugation device having a stimulated Brillouin scattering (SBS) medium.

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: The invention relates to a microlaser cavity having an active laser medium and reflection means at the entrance and exit of the cavity, characterized in that the reflection means are dimensioned in such a way that, in the active medium, the size of a pumping beam is at the most equal to the size of a laser beam emitted by the cavity.

Abstract: An optical device includes a semiconductor optical modulator element (46) which is connected to an end of a signal line (42) in form of a microstrip high-frequency line and whose other electrode is connected to a ground electrode (48) by a bonding wire (50). The signal line (42) includes first and second line portions (42a, 42b). The first line portion (42a) nearer to the entrance of a high-frequency signal has a width W1 determined to adjust its characteristic impedance to 50.OMEGA. and a length L1 equal to an integer multiple of 1/4 of its own guide wavelength. The second line portion (42b) has a width W2 determined to adjust its impedance to an intermediate value between the impedance of the optical modulator element 46 and the impedance of the first line portion (42a), and a length L2 equal to an integer multiple of 1/4 of its own guide wavelength.

Abstract: The invention relates to a microlaser cavity, with active Q switching, characterized in that it comprises:an active laser medium (20), an input mirror (22) and an output mirror (24, 87) defining the cavity,a micromodulator with frustrated total internal reflection, comprising two microprisms (32, 34) made of a certain material of index n.sub.1 each having at least one planar face (36, 38), the two planar faces being approximately parallel to each other and inclined on the microlaser cavity axis, thereby defining a plate (30) of a certain material of index n.sub.2 less than n.sub.1.means (44, 46, 48, 50, 52, 54) for varying the thickness of the plate.

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: The laser diode (11) of the electro-optical device (10) is frequency-controlled with the aid of a control module (40) comprising a rubidium cell (41) and an optical sensor (42), as well as a further module (43) for controlling the injection current and/or the temperature of the laser diode. A controlling light beam (18) is conveyed by means of a multi-mode optical fiber (14) to the rubidium cell. The optical sensor measures the intensity of the light beam transmitted by the rubidium cell and supplies a signal used by the further module for regulating the injection current and/or the temperature of the laser diode so as to stabilize the frequency of the light (16) emitted. The optical fiber is coupled to the laser module in such a way as to collect part of the light (16, 21) emitted by the front face of the laser diode and reflected by a lens (12) in front of the laser diode. The diode-lens assembly is heat controlled.

Abstract: A folded Q-switched laser cavity uses total internal reflections of prisms to fold the intracavity beam. The index of refraction and the orientation of the prisms are selected to induce a predetermined phase delay between the two orthogonal polarization components of the linearly polarized intracavity beam. The predetermined phase delay rotates the intracavity beam polarization to an orthogonal direction such that an intracavity polarizer rejects the beam and the laser is held off from lasing. An electro-optic Q-switch cell is intermittently turned "on" whereby a second predetermined phase delay is induced onto the intracavity beam. The combination of the two predetermined phase delays results in a beam polarization orientation that is not rejected by the polarizer and the laser is not held off from lasing.

Abstract: Generally and in one form of the invention this is a periodic surface filter comprising at least one element at a surface of the filter and electronic controls to change the optical characteristics of the element. The surface filter is used as a switchable filter in a cavity for a Q-switch.

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 continuous-wave ultraviolet laser light generating apparatus includes a laser light source unit (1) for generating laser light from visible light to near-infrared light, a wavelength converting means (4) which includes an optical resonator (2) and a wavelength convertor (3) disposed in the optical resonator (2) for converting a wavelength of incident laser light and which converts the laser light from the laser light source unit (1) into continuous-wave ultraviolet laser light L.sub.UL to emit the latter, a locking means (5) for adjusting the optical resonator (2) so as to have a predetermined cavity length, and an electrooptic phase modulator (6) for modulating a phase of the laser light from the laser light source unit in response to a resonance frequency of the optical resonator. The electrooptic phase modulator (6) is made of an electrooptic crystal (11) having a composition of ATiOXO.sub.4 where A depicts any one of K, Cs and Rb and X depicts any one of P and As.

Abstract: A system for generating a pulsed laser beam includes a laser source and a mode locker which are mounted in a housing that defines a beam path for light from the laser source. An electro-optical crystal is positioned on the beam path to selectively polarize light traveling along the beam path. In operation, the crystal is repetitively advanced through a three period working cycle. At the beginning of the no-lase period which initiates each working cycle, the electro-optical crystal is partially activated. After a predetermined period, pumping of the laser source begins. Next, in the pulse shaping or pre-lasing period, the mode locker becomes active to produce a single compressed pulse in the laser cavity. After pulse-shaping the system for approximately two-hundred and fifty to three-hundred microseconds, the electro-optical crystal is fully activated to start the amplification period to create an amplified laser pulse. The amplification period lasts for approximately two-tenths of one microsecond (0.2 .mu.

Abstract: A two-step solid state optical switch system includes an electro-optical material positioned between a first electrode and a grounded second electrode. A voltage source is electrically connectable to the first electrode by an ON switch. When the ON switch is closed, a plurality of field effect transistors establish electrical contact between the voltage source and the first electrode to charge the first electrode and change the optical characteristics of the electro-optical material. An OFF switch, which is also electrically connectable to the first electrode, includes a plurality of field effect transistors, which establish electrical contact between ground and the first electrode when the OFF switch is closed. With the closing of the OFF switch, any voltage on the first electrode is removed to restore the optical characteristics of the electro-optical material.

Abstract: A laser cavity configuration employs a mode reshaping structure in a solid state waveguide. The mode reshaping may be by means of an adiabatic taper. Polarization switching may be employed in connection with the mode reshaping to obtain a high output power in a single transverse spatial mode from an integrated external cavity multiple-mode diode laser device. The structure provides stabilization and rapid tuning of the frequency of the diode laser, as well as use substantially all of the available power of the diode laser operating multimode. Various configurations and combinations are described. An advantage is that an integrated structure can provide output of the laser in a waveguide with single mode for subsequent applications. The external cavity diode laser according to the invention is consistent with a planar manufacturing process such that high volume, low cost products can be achieved.

Abstract: A laser cavity configuration employs polarization switching to obtain a high output power in a single transverse spatial mode from an integrated external cavity diode laser device. The structure provides stabilization and rapid tuning of the frequency of the diode laser. An advantage is that an integrated structure provides output of the laser in a waveguide with the correct polarization for subsequent applications while supporting optimal polarization in a solid state active medium. The external cavity diode laser according to the invention is consistent with a planar manufacturing process such that high volume, low cost products can be achieved.

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

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: 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: A semiconductor laser diode is optically coupled to an electro-optic phase modulator and an electrical control signal is applied to the phase modulator to modify its optical gain or loss and its real refractive index, to in turn alter the optical length of the modulator and shift its resonant wavelengths. The result is to tune the laser diode. A facet of the laser diode is anti-reflection coated to minimize interface loss between the laser diode and the phase modulator.

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 light shutter array to be employed in an optical head for a color display, a color printer or the like. The light shutter array has at least three lines of shutter elements which are made of a material having an electrooptic effect. In tile lines, shutter elements which have conductor-filmed windows and shutter elements which have bare windows are staggered. The shutter elements with bare windows function as light shutters, and the shutter elements with conductor-filmed windows function as electrodes. The shutter elements with bare windows in each line are driven in accordance with red, green or blue image data.

Abstract: The short optical pulse generator is provided with a semiconductor laser which oscillates continuously at a single wavelength, a semiconductor electro-absorption type optical modulator which performs the intensity modulation of the output light from the laser, and a sinusoidal voltage generator and a DC voltage generator for driving the electro-absorption type optical modulator. A DC voltage is applied to the electro-absorption type optical modulator so that the output light from the laser is sufficiently extinguished. By applying a sinusoidal voltage to the optical modulator, short optical pulses are generated.

Abstract: The optical modulator of the invention comprises an electro-optic material or magneto-optic material EOD which modulates optical energy in accordance with an applied electromagnetic waveform. The electromagnetic waveform impressed in the EOD is controlled by a light activated switch, or switches, which varies the magnitude of the electromagnetic waveform to the EOD by switching portions of a transmission line (of which the EOD forms all or at least a part of the dielectric) in or out. The switch, or switches, may be configured between segments of one of the conductors of the transmission line and may overlay the electro-optic dielectric material. The transmission line may include a plurality of sections, each charged to a selected voltage, so that when switched by said light activated switches, the electromagnetic waveform to the EOD is controlled. When used in a laser cavity, the optical modulator can control the output of the laser cavity in response to optical input control signals.

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

Abstract: An optical modulator comprises a crystal (15) of material exhibiting the pyroelectric effect, and charge-dissipating means for dissipating any charge built up on the optical faces of the prism. The charge-dissipating means may comprise point electrodes (30) positioned adjacent to the optical faces (21) of the crystal and connected to an alternating-current high-voltage power supply (31). The electrodes produce charged ions which neutralize any charge on the optical faces of the crystal. The crystal may be used as the Q-switch in a laser.