Abstract: Provided is a high-repetition-rate femtosecond regenerative amplification system. The regenerative amplification system includes: a laser oscillator emitting pulses; a stretcher stretching the pulses with negative dispersion; a regenerative amplifier amplifying the pulses, the regenerative amplifier comprising an acousto-optic modulator for pulse switching, a pulsed pump laser for pumping a gain medium, a resonator for reciprocating the pulses between a plurality of mirrors, and at least one chirped mirror for providing negative dispersion; and a glass compressor compressing the pulses. Accordingly, the 100 kHz-class high-repetition-rate femtosecond regenerative amplification system can produce an output energy of tens of ?J, higher than a few ?J provided by a conventional system.

Abstract: A light pulse conditioning apparatus has at least first and second curved reflective surfaces that share a common focus and a light-redirecting element disposed between the first and second curved reflective surfaces to redirect at least a portion of an incident light beam toward the second curved reflective surface as a delayed beam portion. A beam-shifting compensating element is disposed between the first curved reflective surface and the light-redirecting element and in the path of the delayed beam portion, for shifting the optical path of the delayed beam portion as it returns toward the light-redirecting element.

Abstract: A pulsed CO2 laser is Q-switched by an intracavity acousto-optic (AO) Q-switch including an AO material transparent at a fundamental wavelength of the laser. In one example the AO material is germanium.

Abstract: In the case where, e.g., because of provision of a high-gain and high-energy Q-switched laser oscillator in a laser system in a MOPA configuration, the duration ?z from the time point when oscillation-stage Q switches (13a and 13b) start the gate ON to the time point when a pulse laser beam (18) starts to grow is shorter than the fall time ?f of amplification-stage Q switches (13c, 13d, and 13e), by implementing control in such a way that the gate-ON timing of the oscillation-stage Q switches (13a and 13b) lag behind the gate-ON timing of the amplification-stage Q switches (13c, 13d, and 13e) by a predetermined time, the loss in the pulse laser beam (18) at the amplification-stage Q switches (13c, 13d, and 13e) can be prevented, while the gain deterioration due to a spontaneously amplified ray (17) produced in the amplification stage is being suppressed. Therefore, a high-energy pulse laser beam can efficiently be obtained.

Abstract: An apparatus for adjusting the wavelength of a laser capable of lasing at multiple wavelengths by using a single acousto-optical modulator and a pair of optical reflectors inside a laser cavity. By adjusting the frequency and amplitude of the radio-frequency source to the acousto-optical modulator, undesired wavelengths are suppressed in the laser cavity, leaving appreciable gain only at the desired wavelength.

Abstract: A device producing laser pulses of durations smaller than 30 ns, and including along its internal optical axis: a laser resonator of optical length smaller than 2 m including two reflecting ends and incorporating an MPF photonic fiber pumped continuously by at least one pump wave with laser diodes, the laser medium being a medium where the laser wave is guided and has a gain with very weak signal greater than 10 per passage, the resonator also incorporating an optical modulator. The optical modulator may deflect the internal laser axis via an electric control along two stable directions, the first direction corresponding to an axis along which the internal laser beam undergoes sufficient losses to prevent the laser effect, the second direction corresponding to an axis along which the laser beam is reflected towards itself at least partially by an optical return element.

Abstract: A narrow linewidth, injection seeded, Q-switched Er fiber ring oscillator, that provides over 600 ?W of average output power at 500 Hz, with 1.2 ?J per pulse, before the output appears to be significantly affected by stimulated Brillouin scattering. This laser configuration provides multiple advantages in LIDAR systems because it offers the possibility of broad and rapid tunability.

Abstract: An acousto-optic modulator for a Q-switch (300) for a laser includes a monolithic acousto-optic (a-o) medium (311), a series of at least two acoustic transducers (321, 322), bonded spaced apart on the a-o medium, which emit first and second columnar acoustic beams (331, 332). These interact sequentially with an incident optical beam (Light) passing through the modulator. The transducers are oriented so that an optical ray (342) diffracted from the first acoustic column region enters the second acoustic column region at an angle outside the “acceptance angle” of the second acoustical column, i.e. outside the range of incidence angles for which the diffraction efficiency is significant, whereas the remaining light in the zeroth order will undergo further diffraction at the second acoustic column region. This arrangement significantly reduces the amount of light diffracted by the first beam being diffracted back into the zeroth order by the second acoustic beam.

Abstract: A corrosion resistant fluid cooled acousto-optic (AO) device includes an AO interaction medium and a piezoelectric transducer affixed to the AO medium. A cooling arrangement is thermally coupled to the AO medium and includes a first material, and at least one cooling conduit in thermal contact within the first material formed from a second different material having an inlet and an outlet coupled thereto. The conduit provides a channel having an inner surface for flowing a coolant fluid therethrough, wherein the conduit includes a continuous corrosion resistant material layer over its entire area of the inner surface. The first material provides a specific acoustic impedance closer to a specific acoustic impedance of the AO medium as compared to the corrosion resistant material, and a bulk thermal conductivity at 25 C of at least 75 W/m·K.

Abstract: A corrosion resistant fluid cooled acousto-optic (AO) device includes an AO interaction medium and a piezoelectric transducer affixed to the AO medium. A cooling arrangement is thermally coupled to the AO medium and includes a first material, and at least one cooling conduit in thermal contact within the first material formed from a second different material having an inlet and an outlet coupled thereto. The conduit provides a channel having an inner surface for flowing a coolant fluid therethrough, wherein the conduit includes a continuous corrosion resistant material layer over its entire area of the inner surface. The first material provides a specific acoustic impedance closer to a specific acoustic impedance of the AO medium as compared to the corrosion resistant material, and a bulk thermal conductivity at 25 C of at least 75 W/m·K.

Abstract: The invention relates to a method and device for controlling the amplitude of the wavelength spectrum of ultra-short light pulses emitted by multipass laser amplifiers. According to the invention, a programmable acousto-optic device (8) is introduced into a laser cavity of a multipass amplifier (10), in order to modify slightly the amplitude of the spectrum of the light pulse with each passage, owing to a collinear or quasi-collinear interaction between the light pulse and a sound beam, the result from the filtering being used on the non-diffracted direct light beam from the acousto-optic interaction.

Abstract: Multiple laser resonators share a common acousto-optic Q-switch. The Q-switch is driven by a radio-frequency (RF) transducer that causes an acoustic wave to propagate in the Q-switch. Turning off the RF transducer discontinues propagation of the acoustic wave and causes each of the laser resonators to deliver an optical pulse. The finite velocity of the acoustic wave causes the pulses to be delivered temporally spaced apart.

Abstract: A laser for generating pulsed laser radiation is provided. The laser includes a resonator, a laser-active medium arranged in the resonator, and an acousto-optic modulator arranged in the resonator. The modulator can be put in a first and a second state so as to set the resonator quality, the resonator quality being lower in the first state than in the second state, and comprising a control unit for controlling the modulator. The control unit effects phase-locked coupling of a high-frequency signal to be applied to the modulator in one of said two states, in order to generate a predetermined sound field in the modulator, and a switching signal designed to switch the modulator periodically between the two states.

Abstract: An end face structure of an optical fiber includes a coreless fiber fused to an emitting end face of the fiber optical fiber and a coating material disposed around at least the coreless fiber, a refractive index of the coating material being higher than a refractive index of the coreless fiber.

Abstract: A non-linearly frequency-converted Q-switched laser is “injection seeded” with short pulses from another laser, called a seed laser. Radiation produced by the Q-switched laser is frequency converted in a non-linear process. The injection seeding can enhance peak power and frequency conversion efficiency while reducing damage to a non-linear medium used to frequency convert radiation generated by the Q-switched laser.

Abstract: All optical clock recovery includes a transmitter for generating an optical timing signal. The transmitter includes a semiconductor laser for the production of a dynamically synchronizable timing signal, the laser having an external resonator for feedback of the timing signal to the laser, the feedback having a delay time greater than a relaxation oscillation time for the laser, and the laser outputting an optical timing signal having a characteristic dynamic. The transmitter supplies the optical timing signal to a receiver configured to receive the timing signal and to synchronize to the laser on receipt of the timing signal, such that the receiver outputs a recovered timing signal having the characteristic dynamic.

Abstract: An optical tunable laser design (100) for the optic telecommunication industry is disclosed in this invention. This new design is economical, reliable, robust and with superior optical performances. The design offers broadband tunability, high output power, narrow laser line-width and high SMSR. And in addition, the tunable laser is distinguishable from conventional designs by the mere facts that there are no moving parts, therefore, making it very reliable, and the tuning method of this invention is non-thermal and non-mechanical making its tuning very fast in the sub-millisecond range. In the manufacturing front, it is low cost and easy to produce. It can be achieved with automation equipment like those used in the IC placement and PC assembly industry, therefore, the products as that disclosed in this invention can be provided with significantly reduced production costs and marketed with very competitive price.

Abstract: In a first embodiment, the invention makes use of a Neodymium doped YAG (Nd: YAG) gain medium placed in an optical resonant cavity formed by two mirrors. Power extraction is maximized for a specific laser cavity. In particular the concave curvature on the rod ends contributes a negative lensing component to modify the strength of the thermal lens. In a second embodiment the present invention uses an amplifier rod medium with curved ends to act as lensing elements to collect emission from the laser gain medium and/or oscillator described in the first embodiment of the invention. The combination of thermal lens and curved rod ends produces a lensing effect which allows light to be directly coupled from a laser. In addition, variation of the input pump power allows for control of the thermal lens formed within the amplifier rod.

Abstract: A laser apparatus for generating optical pulses is disclosed, said laser apparatus has a reflecting gain element preferably including a fiber gain medium. The reflecting gain element is coupled to a controllable reflecting/transmitting module having a reflecting state and a transmitting state, wherein the controllable reflecting/transmitting means are operable to switch from the transmitting state to the reflecting state to initiate a build-up of an optical pulse, and to switch back to the transmitting state for outputting the optical pulse before it reaches the reflecting/transmitting means after a cavity roundtrip. In a preferred embodiment, the controllable reflecting/transmitting module includes an acousto-optic switch at an output end of a laser operable to output the optical pulse in zeroth diffraction order.

Abstract: A laser system for generating at least one pulse and/or pulse sequence(s) of pulses having at least one specified property, such as pulse energy, duration, peak intensity, pulse form and/or timing includes an amplifying cavity. The amplification process is monitored in the amplifying cavity to obtain data about at least one property of the pulse sequence and/or the single pulse(s). The system also compares the obtained data with reference data and it controls at least one switching means for inputting, outputting and/or retaining the pulse(s) in the amplifying cavity such that at least one property of the pulse sequences and/or the pulses at an output of the laser system has substantially a specified value.

Abstract: All optical clock recovery includes a transmitter for generating an optical timing signal. The transmitter includes a semiconductor laser for the production of a dynamically synchronizable timing signal, the laser having an external resonator for feedback of the timing signal to the laser, the feedback having a delay time greater than a relaxation oscillation time for the laser, and the laser outputting an optical timing signal having a characteristic dynamic. The transmitter supplies the optical timing signal to a receiver configured to receive the timing signal and to synchronize to the laser on receipt of the timing signal, such that the receiver outputs a recovered timing signal having the characteristic dynamic.

Abstract: A laser output beam is directed into an acousto-optic cell. The acousto-optic cell is driven by RF voltages at a plurality of different frequencies. Portions of the laser output beam are diffracted by the acousto-optic cell at a plurality of different angles corresponding the different drive frequencies. The different portions of the output beam define a plurality of secondary beams. The magnitude of the RF voltages applied to the acousto-optic cell and the power in the laser output beam may be cooperatively varied to provide a predetermined power in each of the secondary beams.

Abstract: A pulsed laser system includes a laser pump, a laser rod, a reflector interposed between the laser pump and the laser rod, through which energy from the laser pump enters the laser rod, an output reflector through which energy is emitted from the laser rod, a switch interposed between the laser rod and the output reflector, and a control device. The switch, when closed, causes energy to be stored in the laser rod and, when opened, allows energy to be emitted from the laser rod during an emission period. The control device allows a primary laser pulse emitted from the laser rod during the emission period to impinge on a workpiece and blocks from the workpiece secondary laser emission occurring during the emission period after emission of the primary pulse. The pulsed laser system is operated over a range of repetition rates, so as to cause laser energy to be emitted during a plurality of emission periods at each repetition rate.

Abstract: An optical tunable laser design for the optical telecommunication industry is disclosed in this invention. This new design is economical, reliable, robust and with superior optical performances. The design offers broadband tunability, high output power, narrow laser line-width and high SMSR. And in addition, the tunable laser is distinguishable from conventional designs by the mere facts that there are no moving parts, therefore, making it very reliable, and the tuning method of this invention is non-thermal and non-mechanical making its tuning very fast in the sub-millisecond range. In the manufacturing front, it is low cost and easy to produce. It can be achieved with automation equipment like those used in the IC placement and PC assembly industry, therefore, the products as that disclosed in this invention can be provided with significantly reduced production costs and marketed with very competitive price.

Abstract: The present invention is a method of determining formation horizontal shear wave velocity, formation transverse isotropy and an effective logging tool modulus. The method comprises determining an effective logging tool modulus by modeling the logging tool as a fluid filled cylindrical shell. Measured Stoneley-wave slowness values are acquired for a formation. A horizontal formation shear wave velocity, Vsh, is calculated as a function of the measured Stoneley-wave slowness and an estimated Stoneley-wave slowness wherein the estimated average Stoneley-wave slowness is computed using the effective tool modulus. A difference between the measured Stoneley-wave slowness and the estimated Stoneley-wave slowness is minimized and the horizontal shear-wave velocity value for the minimized difference is output. Transverse isotropy may be then be calculated as a function of the determined Vsh and vertical shear wave velocity, Vsv, determined from standard logging techniques.

Abstract: A broadband laser source comprising: a resonant cavity (1) containing a medium (2) which emits optical energy (3) in a continuum of wavelengths in response to application of pump energy (4) to the medium (2); a source of pump energy (5) for producing said optical energy (3); a frequency shifter (6) within the resonant cavity (1); and a tuneable spectral filter (7) within the resonant cavity (1), and the apparatus being such that in use the tuneable spectral filter (7) has a peak wavelength which is repeatedly swept in a substantially resonant fashion over a wavelength range equal to, or a fraction of, a linewidth of the broadband source such that the rate of change of the peak wavelength of the tuneable spectral filter (7) is substantially equal to the rate of change of the frequency of the optical energy (3) as it is frequency shifted within the resonant cavity (1) by the frequency shifter (6).

Abstract: A tunable laser device produces a laser energy over a range of frequencies. A property of an ultrasonic transducer or, more specifically, the frequency of an ultrasonic wave created by the ultrasonic transducer is altered to change the laser frequency of the tunable laser device. The ultrasonic transducer may couple its ultrasonic wave directly into the laser source or may form a tunable acousto-optic modulator external to the laser source. In both cases, the ultrasonic wave creates an index of refraction perturbation in an optical substrate, through which the laser energy of the laser source passes. Changes in the ultrasonic wave cause changes in the perturbation through which the laser energy passes, which in turn, changes the frequency of the laser energy, thereby enabling the frequency of the laser to be tuned.

Abstract: An electro-optic device for use with a laser beam. A crystal has a first face and a second face. Means are provided for applying a voltage across the crystal to obtain a net phase retardation on the polarization of the laser beam when the laser beam is passed through the crystal. In one embodiment the crystal is composed of a compound having the chemical formula ReAe40(BO3)3 where: RE consists of one or more of the following elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and two other elements Y and Sc; and where Ae is from the list of Ca, Sr, or Ba.

Abstract: A pulsed laser system includes a laser pump, a laser rod, a reflector interposed between the laser pump and the laser rod, through which energy from the laser pump enters the laser rod, an output reflector through which energy is emitted from the laser rod, a switch interposed between the laser rod and the output reflector, and a control device. The switch, when closed, causes energy to be stored in the laser rod and, when opened, allows energy to be emitted from the laser rod during an emission period. The control device allows a primary laser pulse emitted from the laser rod during the emission period to impinge on a workpiece and blocks from the workpiece secondary laser emission occurring during the emission period after emission of the primary pulse. The pulsed laser system is operated over a range of repetition rates, so as to cause laser energy to be emitted during a plurality of emission periods at each repetition rate.

Abstract: A virtual coherent signal controlled laser oscillator for use in optical phase locked coherent receivers. The present invention employs a fixed laser oscillator in combination with a signal controlled microwave oscillator. A single sideband mixer processes the signals output by the laser oscillator and microwave oscillator to generate a single controlled optical frequency signal.

Abstract: A method and apparatus for accurately and precisely controlling the frequency (wavelength) and periodic frequency modulation of a laser are provided. An ADC (Analog to Digital Converter) is used to sample the output of a modified interferometer used as a delay line discriminator, and quadrature components of the sampled output are generated. An arctangent function (e.g., atan2) is applied to convert the quadrature components to a phase measure that is proportional to the laser frequency. Correlator circuits (e.g., cost-efficient correlator circuits) are provided to extract average frequency, modulation peak deviation, and modulation phase error signals. Control-loop feedback using the extracted signals is used to adjust the average frequency, modulation deviation, and modulation phase to respective set points.

Abstract: An acousto-optical add/drop multiplexer includes an acousto-optical switch including a first optical port coupled to a first polarization splitter, at least one polarization converter coupled between the first polarization splitter and a second polarization splitter, and second and third optical ports coupled to the second splitter. A first circulator is coupled to the first optical port, a mirror is coupled to the second optical port, and a second circulator is coupled to the third optical port. A wavelength selective optical cross-connect may be realized by coupling two such acousto-optical add/drop multiplexers by a single optical fiber to their respective third optical ports.

Abstract: A passively mode-locked optically pumped semiconductor vertical-external-cavity surface-emitting laser (OPS-EXSEL) is disclosed. The laser is mode locked by a semiconductor saturable absorber mirror (SESAM) which forms part of an external cavity. Both the beam-quality limitations of edge-emitting lasers, and the power restrictions of electrically pumped surface-emitting lasers are overcome. The laser uses a semiconductor wafer in which a stack of quantum wells is grown adjacent to a single Bragg-mirror structure. Light from one or more multi-mode high-power diode lasers is focused onto the face of the wafer and pumps the wells by absorption in the barrier regions. The area of the laser mode on the active mirror can be about 104 times larger than the mode area on the facet of an edge-emitting laser, offering scope for the generation of high average power and large pulse energy. At the same time the external cavity enforces fundamental mode operation in a circular, near-diffraction-limited beam.

Abstract: An acousto-optic tunable filter that includes a polarization beamsplitter, a multi-segment interaction region and a polarization beam combiner is described. The polarization beamsplitter generates a first and a second polarized optical signal. The multi-segment optical interaction region includes a first optical interaction region and a first acoustic wave generator that generates acoustic waves in the first optical interaction region. The multi-segment optical interaction region also includes a second optical interaction region that is non-collinear relative to the first optical interaction region and a second acoustic wave generator that generates acoustic waves in the second optical interaction region. Optical signals that are phase-matched to the acoustic waves are mode-converted in response to the acoustic waves. The acousto-optic tunable filter also includes a polarization beam combiner that generates both a mode-converted optical signal and a non-mode-converted optical signal.

Abstract: The present invention has applications in high-bandwidth communications systems and other applications that utilize modulated optical energy. In one aspect of the invention, a short cavity diode-pumped laser generates optical energy that may be modulated over a wide range of frequencies. In one embodiment, the short cavity diode-pumped laser may be modulated at rates up to 15 GHz. The short cavity diode-pumped laser may include a laser diode modulator and a laser coupled to the laser diode modulator having a cavity lifetime of less than about 100 picoseconds.

Abstract: The present invention relates to an integrated light source having first and second optical waveguides defining a first optical coupling region for coupling light therebetween. At least one of the optical waveguides includes a gain medium configured to emit light upon irradiation. The light source also includes a first acoustic wave source to subject the first optical coupling region to acoustic waves having a longitudinal frequency &ohgr;AC1, whereby a frequency of light propagating along one of the first and second waveguides differs from a frequency of light propagating along the other waveguide by an amount by an amount &ohgr;AC1.

Abstract: For the sake of no needing to provide a mechanically actuating section such as a rotating mechanism thereby to be capable of realizing stable ultrashort pulse laser oscillation, an ultrashort pulse laser oscillator comprises a laser resonator composed of a mirror on outgoing side, and a total reflection mirror; a continuous wave oscillation laser for inputting excitation laser beam; a tunable laser medium capable of laser oscillation; a photoacoustic optical crystal having birefringent property as a crystal for selecting wavelength to which is input outgoing light from the tunable laser medium; a piezoelectric element inputting an acoustic wave having a frequency in response to a distortion upon application of voltage; a power source for applying the voltage; and a control means for controlling a frequency of voltage to be applied to the piezoelectric element by the power source wherein a frequency of voltage to be applied to the piezoelectric element by the power source is controlled by means of the control

Abstract: An intracavity frequency converted, Q-switched laser and method for operating such laser to obtain high output power in secondary pulses at a converted frequency. The secondary pulses are generated by a intracavity frequency conversion element from primary pulses at the fundamental wavelength. In accordance with the invention, after the primary and secondary pulses are generated the Q-switch is turned back on before the gain is fully depleted in the generation of the primary pulse. In particular, the Q-switch is turned back on such that a certain amount of energy of the primary pulse is retained in the laser, but late enough so that a majority of the secondary pulse is out-coupled from the laser. The Q-switched laser is well-suited for use at pulse repetition rates larger than 1/&tgr;, where &tgr; is an upper state lifetime (fluorescence lifetime) of the laser. Specifically, the laser can be operated at repetition rates of 10 kHz and higher, e.g.

Abstract: An optical channel monitor (OCM) or filter for analyzing an incident light carrying a number of narrow band signal channels such as WDM or DWDM channels. The OCM or filter use an acousto-optic tunable filter to receive and refract from an incident light a refracted light such that the refracted light contains a test channel with a center frequency &ngr;0. A first birefringent element is provided for filtering from the refracted light a first polarized light and a second polarized light orthogonal to the first polarized light. The transmission curves are engineered such that the transmissions of the first and second polarized light are substantially equal at the center frequency &ngr;0 of the test channel. The OCM or filter has a second birefringent element for filtering from the first polarized light a first polarized portion and a second polarized portion.

Abstract: A method and apparatus for accurately and precisely controlling the frequency (wavelength) and periodic frequency modulation of a laser are provided. An ADC (Analog to Digital Converter) is used to sample the output of a modified interferometer used as a delay line discriminator, and quadrature components of the sampled output are generated. An arctangent function (e.g., atan2) is applied to convert the quadrature components to a phase measure that is proportional to the laser frequency. Correlator circuits (e.g., cost-efficient correlator circuits) are provided to extract average frequency, modulation peak deviation, and modulation phase error signals. Control-loop feedback using the extracted signals is used to adjust the average frequency, modulation deviation, and modulation phase to respective set points.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A Q-switched solid state laser is disclosed comprising a pump radiation source, whose pump radiation is focused through focusing elements in the laser crystal, a resonator formed by reflecting surfaces in which at least one laser crystal, an acousto-optic switch for Q-switching, and, if desired, a freqency-doubling crystal (KTP) are arranged. The acousto-optic Q-switch is connected with an electronic unit generating a high-frequency wave which can be modulated. The Q-switch is controlled by the high-frequency wave in such a way that laser pulses with pulse lengths on the order of magnitude of several microseconds (&mgr;s) and with an energy content on the order of magnitude of several millijoules can be generated by controlling the steepness of the edge of the modulation function of the high-frequency wave.

Abstract: The invention relates to an optical modulation device for coupling an entering radiation field (12), with which an incident radiation field (40) is divided into a transmitted branch (40T) and a diffracted branch (40B) by means of a first acousto-optical modulation and a diffracted and a transmitted branch are respectively generated by means of a second acousto-optical modulation so that the transmitted branch (40BUT) resulting from the deflected diffracted branch (40BU) and the diffracted branch (40TUB) resulting from the deflected transmitted branch (40TU) propagate in approximately the same direction and form a first radiation field (46) as a result of essentially constructive interference and, in addition, the transmitted branch (40TUT) resulting from the deflected transmitted branch (40TU) and the diffracted branch (40BUB) resulting from the deflected diffracted branch (40BU) propagate in the same direction and form a second radiation field (48) as a result of essentially destructive interference.

Abstract: A Q-switch modulator for a high power laser having a randomly polarized output beam and large divergence angle employs a cascaded arrangement of longitudinal mode acousto-optic modulators, each of which has a Raman Nath or near Raman Nath interaction length. The modulators are optically cascaded such that the distance the randomly polarized laser beam travels through the modulators is effectively confined to the sum of the non coherent interaction lengths thereof. Due to the substantial power level of the laser output, there is heating of the bulk material, which usually results in a shift in the Bragg angle. This has minimal if any effect on the shorter interaction length of the Q-switch modulator of the invention. Also, heating of the bulk material is countered by the incorporation of cooling fluid channels in a heat sink support block coupled in thermal communication with the bulk material.

Abstract: A quasi-CW diode- or lamp-pumped, A-O Q-switched solid-state UV laser system (10) synchronizes timing of the quasi-CW pumping with movement of the positioning system (36) to reduce pumping while the positioning system (36) is moving from one target area (31) to the next target area (31) to form multiple vias in a substrate at a high throughput. Thus, the available UV power for via formation is higher even though the average pumping power to the laser medium (16), and thermal loading of the laser pumping diodes (14), remains the same as that currently available through conventional CW pumping with conventionally available laser pumping diodes (14). The quasi-CW pumping current profile can be further modified to realize a preferred UV pulse amplitude profile.

Abstract: A double-passage acousto-optical device including an acousto-optical switch having a first polarization conversion region connected between first input and output ports, and a second conversion region connected between second input and output ports; and an optical combination connected between the first output port and the second input port via optical fibers and including an optical isolating element. The double-passage acousto-optical device may alternately include an acousto-optical switch including a single polarization conversion region connected between first input and output ports and also connected between second input and output ports. A bandpass filter, a notch filter, and add/drop and a tunable laser generator may be formed using the acousto-optical device.

Abstract: A pulsed laser system includes a laser pump, a laser rod, a reflector interposed between the laser pump and the laser rod, through which energy from the laser pump enters the laser rod, an output reflector through which energy is emitted from the laser rod, a switch interposed between the laser rod and the output reflector, and a control device. The switch, when closed, causes energy to be stored in the laser rod and, when opened, allows energy to be emitted from the laser rod during an emission period. The control device allows a primary laser pulse emitted from the laser rod during the emission period to impinge on a workpiece and blocks from the workpiece secondary laser emission occurring during the emission period after emission of the primary pulse. The pulsed laser system is operated over a range of repetition rates, so as to cause laser energy to be emitted during a plurality of emission periods at each repetition rate.

Abstract: A Q-switched solid state laser is disclosed comprising a pump radiation source, whose pump radiation is focused through focusing elements in the laser crystal, a resonator formed by reflecting surfaces in which at least one laser crystal, an acousto-optic switch for Q-switching, and, if desired, a freqency-doubling crystal (KTP) are arranged. The acousto-optic Q-switch is connected with an electronic unit generating a high-frequency wave which can be modulated. The Q-switch is controlled by the high-frequency wave in such a way that laser pulses with pulse lengths on the order of magnitude of several microseconds (&mgr;s) and with an energy content on the order of magnitude of several millijoules can be generated by controlling the steepness of the edge of the modulation function of the high-frequency wave.

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 laser writing system includes a high reflector and an output coupler that define an oscillator cavity. A gain medium and a mode locking device are positioned in the oscillator cavity. A diode pump source produces a pump beam that is incident on the gain medium and an output beam is produced. A support holds a workpiece. Means are provided for directing the output beam across the workpiece.