Abstract: A Ramsey spectrometer is provided with an optical path, an optical path length stabilization circuit configured to stabilize a length of the optical path, a modulator optically connected to the optical path, the modulator being configured to generate resonant laser light of a first frequency f1 that causes a resonance of an atom, a molecule, or an ion as a spectroscopic target in pulses a plurality of times and generates non-resonant laser light of a second frequency f2 that does not cause the resonance, and a spectroscopic unit configured to spectroscope the spectroscopic target. The spectroscopic unit detects a state change of the spectroscopic target corresponding to the first frequency f1, the state change being caused by irradiating the resonant laser light to the spectroscopic target.

Abstract: An electric field measuring apparatus includes an electrostatic chuck with a through hole and holding a wafer, a lift pin picking up the wafer, a driver vertically moving the lift pin along the through hole, a probe in the lift pin and having a refractive index changed by an electric field of the wafer, the probe including an electro-optical crystal, an optical waveguide forming at least one internal path of light having a polarization characteristic changed by the changed refractive index between the probe and the wafer, and a control module controlling the lift pin and the driver. The lift pin moves to first and second positions. The control module calculates a strength of the electric field of the wafer, using electric field data measured using the probe at each of the first and second positions.

Abstract: Certain embodiments describe an endoilluminator having a tube that includes an interior compartment between a proximal end and a distal end of the tube, wherein the distal end of the tube is configured to be inserted into an eye. The endoilluminator also includes a handpiece coupled to a light source and the proximal end of the tube, wherein the endoilluminator is configured to filter an incident component of light transmitted by the light source and emit a polarized component of the transmitted light through the distal end of the tube.

Abstract: A method of additive manufacture is disclosed. The method may include providing a powder bed and directing a shaped laser beam pulse train consisting of one or more pulses and having a flux greater than 20 kW/cm2 at a defined two dimensional region of the powder bed. This minimizes adverse laser plasma effects during the process of melting and fusing powder within the defined two dimensional region.

Abstract: Systems, methods, and devices for hyperspectral imaging with a minimal area image sensor are disclosed. A system includes an emitter for emitting pulses of electromagnetic radiation and an image sensor comprising a pixel array for sensing reflected electromagnetic radiation, wherein the pixel array comprises active pixels and optical black pixels. The system includes a black clamp providing offset control for data generated by the pixel array and a controller comprising a processor in electrical communication with the image sensor and the emitter. The system is such that at least a portion of the pulses of electromagnetic radiation emitted by the emitter comprises one or more of electromagnetic radiation having a wavelength from about 513 nm to about 545 nm, electromagnetic radiation having a wavelength from about 565 nm to about 585 nm, or electromagnetic radiation having a wavelength from about 900 nm to about 1000 nm.

Abstract: A laser pulse generator includes a pulse shape generation device and a clock unit. The generation device includes a pulse shape repository, a digital-to-analog converter (DAC), a first terminal for connecting a start signal line, a second terminal for connecting a clock signal line, and a third terminal for connecting a pulse line. The first and second terminals are connected to the pulse shape repository and the DAC such that when a predefined start signal is present, data is transferred from the pulse shape repository to the DAC and converted by the DAC into an output pulse, for example, at a rate of a clock signal. The output pulse is supplied at the third terminal for actuating a driver of a laser diode. The clock unit is connected to the second terminal via the clock signal line and includes a reset terminal connected to the start signal line.

Abstract: When a soliton and a dispersive pulse propagate in an optical fiber, they can interact via cross-phase modulation, which occurs when one pulse modulates the refractive index experienced by the other pulse. Cross-phase modulation causes each pulse to shift in wavelength by an amount proportional to the time delay between the pulses. Changing the time delay between the pulses changes the wavelength shift of each pulse. This make it possible to produce pulses whose output wavelengths can be tuned over large ranges, e.g. hundreds of nm, in a time as short as the pulse repetition period of the laser (e.g., at rates of megahertz or gigahertz). Such a laser requires no moving parts, providing high reliability. The laser's optical path can be made entirely of optical fiber, providing high efficiency with low size, weight, and power consumption.

Abstract: A COB bonding laser diode interface mating device comprises a laser diode and a driver integrated circuit (2). The laser diode includes a light-emitting chip (11). The light-emitting chip (11) is a bare die directly bonded to a circuit board. The driver integrated circuit (2) is a driver chip that is a packaged chip. The light-emitting chip (11) and the driver chip are connected through a capacitor-resistor network (3). The capacitor-resistor network (3) allows the driver integrated circuit (2) to provide a bias current and a modulation current to the laser diode such that the laser diode is in an activated state. The capacitor-resistor network (3) realizes interface mating between the COB bonding laser diode and the driver integrated circuit (2), thereby solving a problem that the interface mating cannot be easily achieved, reducing costs, and improving production efficiency.

Abstract: A method for transmit timestamp autocalibration includes generating a calibration pulse for calibrating a transmit timestamp in a transmitting device. The method further includes applying the calibration pulse to a transmit data pipeline in the transmitting device. The method further includes sampling a transmit timestamp when the calibration pulse reaches a timestamp sample triggering location in the transmit data pipeline upstream from an egress point of the transmitting device. The method further includes measuring a latency between a time that the calibration pulse reaches the timestamp sample triggering location and a time that the calibration pulse reaches a location downstream from the timestamp sample triggering location. The method further includes generating an adjusted timestamp based on the measured latency and inserting the adjusted timestamp into a data packet to be transmitted from the transmitting device.

Abstract: Laser-apparatus includes a fiber-MOPA arranged to deliver amplified seed optical pulses having a wavelength of about 1043 nanometers to a multi-pass ytterbium-doped yttrium aluminum garnet solid-state optical amplifier for further amplification.

Abstract: The present invention relates an apparatus and method for measuring range-resolved atmospheric sodium temperature profiles using a space-based Lidar instrument, including a diode-pumped Q-switched self-Raman c-cut Nd:YVO4 laser with intra-cavity frequency doubling that could produce multi-watt 589 nm wavelength output. The c-cut Nd:YVO4 laser has a fundamental wavelength that is tunable from 1063-1067 nm. A continuous wave narrow linewidth diode laser is used as an injection seeder to provide single-frequency grating tunable output around 1066 nm. The injection-seeded self-Raman shifted Nd:VO4 laser is tuned across the sodium vapor D2 line at 589 nm. In one embodiment, a space-qualified frequency-doubled 9 Watt at 532 nm wavelength Nd:YVO4 laser, is utilized with a tandem interference filter temperature-stabilized fused-silica-etalon receiver and high-bandwidth photon-counting detectors.

Abstract: Disclosed is a full-laser scribing method for a large-area copper indium gallium selenide (CIGS) thin-film solar cell module, including: using a laser I to scribe a molybdenum thin film prepared on soda-lime glass to form a first scribed line (P1); preparing the following film layers in sequence on the molybdenum layer in which P1 has been scribed: a CIGS layer, a cadmium sulfide layer and an intrinsic zinc oxide layer; after finishing preparation of the above film layers, using a laser II for scribing to form a second scribed line (P2), wherein the scribed line P2 is parallel with the scribed line P1; and preparing an aluminum-doped zinc oxide layer on the intrinsic zinc oxide layer in which P2 has been scribed, and using a laser III for scribing to form a third scribed line (P3), wherein the scribed line P3 is parallel with the scribed line P1.

Abstract: The semiconductor laser driving circuit that controls an overshoot on modulation includes a semiconductor laser, of which anode is connected to a power source, that emits the laser light that is modulated by an external modulation input signal, an impedance element connected to a cathode of the laser device, an impedance element connected to the anode, and a collector of a transistor Q1, connected to the impedance element; a collector of a transistor Q2, connected to the other end of the impedance element, a differential pair circuit to which emitters of Q1, Q2 are connected; an electric current source iMOD connected to the emitters of Q1, Q2; and a differential driver that generates a differential voltage (vb1?vb2) that controls Q1, Q2 by driving Q1 by the external modulation input signal, wherein the differential driver controls the differential voltage so that the amplitude of the overshoot of the electric current, which flows in the laser when the output of the laser is at a high-level.

Abstract: A semiconductor laser source includes a structured layer formed on a substrate made of silicon and having an upper face. The structured layer includes a passive optical component chosen from the group composed of an optical reflector and a waveguide. The component is encapsulated in silica or produced on a silica layer. At least one pad extends from a lower face of the structured layer, making direct contact with the substrate made of silicon, to an upper face flush with the upper face of the structured layer. The pad is produced entirely from silicon nitride, in order to form a thermal bridge through the structured layer. An optical amplifier is bonded directly above the passive optical component and partially to the upper face of the pad in order to dissipate the heat that it generates to the substrate made of silicon.

Abstract: An extreme ultraviolet light generating apparatus, may include: a chamber, in which extreme ultraviolet light is generated by plasma being generated in the interior thereof; a window provided in a wall of the chamber; a light source provided at the exterior of the chamber, configured to output illuminating light to the interior of the chamber via the window; a light sensor, configured to detect the illuminating light which is output to the interior of the chamber via the window; a shielding member having an opening that the illuminating light may pass through, that shields the window from emissions from the plasma, provided in the interior of the chamber; and a mirror provided along an optical path of the illuminating light in the interior of the chamber between the window and the shielding member, having a reflective surface that reflects the illuminating light, constituted by a surface of a metal layer.

Abstract: A camera flash comprises a solid-state light source (laser chip) operable to emit excitation light having an emission peak wavelength in a first wavelength range and a photoluminescence wavelength conversion component located remote to the light source. The photoluminescence wavelength conversion component comprises at least one photoluminescence material (phosphor) that is excitable by the excitation light and in response emits light having an emission peak wavelength in a second wavelength range. The light source is configured such that excitation light is incident on an area of the photoluminescence wavelength conversion component less than about 0.01 mm2. The photoluminescence wavelength conversion component can comprise a light reflective or light transmissive component.

Abstract: According to one embodiment, an amplification circuit includes an amplifier having a gain based on a gain control signal and amplifying an input signal by the gain, and a control portion outputting the gain control signal for increasing the gain after decreasing the gain based on an amplitude of the input signal, when the amplitude of the input signal is detected.

Abstract: The invention relates to an apparatus for generating temporally spaced apart light pulses, comprising a first laser (11) which generates a first sequence (I) of light pulses at a first repetition rate, a second laser (12) which generates a second sequence (II) of light pulses at a second repetition rate, and at least one actuating member which influences the first repetition rate and/or the second repetition rate. It is an object of the invention to provide an apparatus for generating temporally spaced apart light pulses which is improved in relation to the prior art.

Abstract: The invention relates to sources of sub-picosecond optical pulses based on single-pass or double-pass optical amplifiers with an optical gain bandwidth in the 2-20 nm range. A passive pulse shaping filter is provided in front of the optical amplifier for pre-shaping seed optical pulses so as to passively pre-compensate for the gain narrowing effect in the optical amplifier. The passive pulse shaping filter may be based on a reflective thin film filter, which may be coupled to a mirror in a multi-pass configuration.

Abstract: In accordance with various aspects of the disclosure, devices and methods are disclosed that include measuring, at a transmitter, a reflected power level corresponding to a specific transmit power level, and setting the transmit power to an operational level. At the transmitter, a new operational level of the transmit power may be determined, for example, by selecting at least one trial transmit power level, and based on reflected power levels measured corresponding to the operational level and the at least one trial level of the transmit power, either maintaining the operational level as the new operational level, or determining the at least one trial level as the new operational level. The operational transmit power level may correspond to a lowest reflected power level, or a highest rate of change of the reflected power level with respect to the transmit power level.

Abstract: A cascaded harmonic generator, for cascaded optical harmonic generation from an optical beam provided by a laser source, may include a second harmonic generator to generate a second harmonic optical beam based on a residual beam associated with the optical beam. The cascaded harmonic generator may include a third harmonic generator to generate a third harmonic optical beam based on the second harmonic optical beam and the optical beam. The third harmonic generator may be positioned in an optical path upstream from the second harmonic generator. A harmonic generator delay time, associated with the optical path, may be approximately equal to, or may be an approximate integer multiple of, a laser source round-trip time.

Abstract: Seed pulse generators for fiber amplifier systems include a seed pump controller coupled to a seed pump laser diode. A photodetector is situated to detect seed pulse generation, and is coupled to the seed pump controller so that seed pumping is decreased upon pulse detection. For a laser diode pump source, a pump current can be pulsed to produce a seed pulse and then decreased to a bias level such as a DC bias current that is less than a pump laser threshold current. Single seed pulses can be generated with reduced pulse jitter.

Abstract: An electro-optic modulator for a laser beam includes an yttrium vanadate crystal cooperative with a double-pass electro-optic switch. A beam to be modulated passes through the yttrium vanadate crystal and makes a forward and a reverse pass through the electro-optic switch. The electro-optic switch returns the beam to the vanadate crystal selectively in one of two polarization orientations at 90 degrees to each other. Depending on the polarization orientation, the returned beam is transmitted by the crystal along a corresponding one of two about-parallel paths spaced apart from each other.

Abstract: Methods and apparatus for generating ultrashort optical pulses. Pulses of an infrared source are launched into an optical fiber characterized by a zero-dispersion wavelength (ZDW), where the wavelength of the infrared source exceeds the ZDW of the optical fiber by at least 100 nm. A resonant dispersion wave (RDW) is generated in the optical fiber that has a central wavelength blue-shifted by more than 500 nm relative to the pump wavelength, and, in some cases, by more than 700 nm. The optical fiber has a core of a diameter exceeding the central wavelength of the RDW by at least a factor of five. In a preferred embodiment, the infrared source includes a master-oscillator-power-amplifier, embodied entirely in optical fiber, and may include an Erbium:fiber oscillator, in particular.

Abstract: Systems and methods are provided for a low frequency AC comparison circuit. The low frequency AC comparison circuit includes circuitry configured to receive a monitoring signal generated by an optical detector, the monitoring signal being proportional to an amount of light generated by an optical transmission device that transmits based on a data signal that is received by an optical driver. The comparison circuit is further configured to generate a modulation current control signal that is transmitted to the optical driver based on a comparison of a low frequency AC component of the monitoring signal and a correlated low frequency AC component of the data signal.

Abstract: The present application relates to comb frequency generator devices generally and more particularly to the use of comb generators for use in fibre optic communications. More particularly, the application provides a frequency comb generator device. The device comprises a laser (30), a biasing circuit for providing a DC bias current (26), an RF circuit (22) providing a RF signal and a drive circuit (28) for combining the RF signal with the DC bias current to provide a drive current to the laser (30). With the DC bias current below threshold of the laser diode and RF bias with a frequence close to the relaxation ascillation frequency of the laser diode, a periodic pulse train is emitted with constant phase.

Abstract: A source of femtosecond optical pulses comprises a seed pulse source arranged to generate seed pulses; an optical amplifier downstream of the seed pulse source, the optical amplifier having a gain bandwidth; a nonlinear optical element downstream of the amplifier, the optical element spectrally broadening optical pulses via a non linear process to have a spectral bandwidth that exceeds the gain bandwidth of the optical amplifier; and a pulse compressor downstream of the nonlinear optical element and arranged to reduce the temporal duration of optical pulses so as to provide output optical pulses having a femtoseconds time duration.

Abstract: An optical pulse generator and a method for using the same, where the optical pulse generator includes a source to deliver a chirped pulse and a chirped pulse compressor, and a first manipulation device and a second manipulation device capable of wavelength dependent manipulating the propagation direction of the chirped pulse and a focusing device having a predetermined focus point. The second manipulation device is arranged after the first manipulation device in propagation direction of the chirped pulse and the first and the second manipulation device are capable of manipulating the propagation direction of the chirped pulse such that the chirped pulse is transformed, after passing the second manipulation device, into a pulse, wherein different chromatic parts of the pulse are spatially spread and temporarily fully aligned.

Abstract: A high power pulsed light generation device includes: a master clock generator that generates a master signal; an optical oscillator that generates a pulsed light synchronized with the master clock signal; an optical amplifier that amplifies the pulsed light emitted from the optical oscillator to output a high power pulsed light; a pump semiconductor laser that generates a pulsed light for pumping the optical amplifier; a driving unit that drives the pump semiconductor laser by a pulsed driving current synchronized with the master clock signal; and a control unit which controls the driving unit and controls a gain of the optical amplifier for each pulse by changing a pulse width of the pulsed drive current from driving unit so as to change the pulse width of the pumping pulsed light.

Abstract: An opto-electronic device (100) for processing optical and electric pulses includes a photoconductor device (10) with a sensor section (11) which is made of a band gap material and which has electrical sensor contacts (12, 13), and a signal processing device (20) which is connected with the sensor contacts (12, 13), wherein the photoconductor device (10) is adapted to create a photocurrent between the sensor contacts (12, 13) in response to an irradiation with ultra-short driving laser pulses (1) having a photon energy smaller than the energy band gap of the band gap material, having a non-zero electric field component (3) oriented parallel with a line (4) between the electrical sensor contacts (12, 13), and causing a charge carrier displacement in the band gap material, and wherein the signal processing device (20) is configured for an output of an electric signal being characteristic for at least one of carrier-envelope phase (CE phase), intensity, temporal properties, spectral intensity and spectral phase

Abstract: In a method for operating a laser system in a Q-switched mode, the laser system provided with a laser resonator with a laser medium and an electro-optical modulator, wherein the electro-optical modulator has an EOM crystal, wherein the EOM crystal has a characteristic ringing time (t0) when subjected to acoustic ringing, the EOM crystal is driven by modulator voltage pulses (pm) having a modulator voltage pulse duration (tml). A train of at least two subsequent laser pulses (pl) is generated. The modulator voltage pulse duration (tml) is selected to be at least approximately equal to the characteristic ringing time (t0) of the EOM crystal multiplied by an integer factor.

Abstract: A semiconductor laser excited solid state laser device and method. The device including a semiconductor laser; a driving device; a solid state laser module which has maximum output efficiency at the set temperature and which generates, from excitation light, an output light of a predetermined output level when the optical noise is at or below a fixed level and the output level of the excitation light is the set output level; a single temperature adjustment device which adjusts the temperature of the semiconductor laser and the temperature of the solid state laser module; and a control device which controls the driving device such that the output light will be at the predetermined output level and controls the temperature adjustment device such that the temperature of the semiconductor laser and the solid state laser module will be the set temperature.

Abstract: A method of controlling output pulses of a pulse laser device (100) including thin-disk laser medium (10), in particular controlling a carrier-envelope phase and/or an intensity noise of the output pulses, includes pumping thin-disk laser medium (10) of pulse laser device (100) with multiple pump laser diodes (21, 22, 23), having at least one modulated laser diode (21, 22) powered by current source (31, 32) with modulation capability, and controlling the output pulses by modulating the output power of the at least one modulated laser diode (21, 22), which is modulated by controlling a drive current thereof, wherein the pump laser diodes further include at least one stable laser diode (23), having constant output power, and the output power of the at least one modulated laser diode (21, 22) is smaller than the whole output power of the stable laser diode(s) (23). A pulse laser device (100) is also described.

Abstract: Systems and methods of optical parametric chirped pulse amplification for laser pulses are provided. Techniques and components include replacing pulse stretcher and/or pulse compressors with chirped volume Bragg gratings (CVBGs) to reduce size, weight, cost, and environmental sensitivity of the laser system.

Abstract: A method of tuning the time duration of laser output pulses, the method including spectrally dispersing optical pulses and further comprising providing an optical pulse having a time duration and a spectral bandwidth; spectrally dispersing (243, 245) the optical pulse so as to provide a selected change in the time duration of the pulse responsive to the spectral bandwidth of the pulse; outputting (226) an optical output pulse having a first time duration that is responsive to the selected change in time duration; providing another optical pulse; changing the amount of spectral bandwidth of the another optical pulse (272) to be different than that of the optical pulse or changing the amount of spectral dispersion so that spectrally dispersing the another optical pulse provides a change in time duration that is different than the selected change; and outputting (226) another optical output pulse having a second time duration that is responsive to the different change in time duration, the second time duration o

Abstract: A variable wavelength diode according to the inventive concept includes a resonator and a plurality of cylindrical lenses. The resonator includes slab waveguides of which resonance lengths are different from each other. The slab waveguides are disposed on a planar light wave circuit (PLC). Thus, the variable wavelength diode realizes a high variation speed and a continuous variation of a beam at the same time.

Abstract: An ultrashort pulse laser processing apparatus for processing a processing target includes: a laser head which includes a seed laser source emitting an ultrashort pulse seed laser, and emits a laser pulse; an optical fiber which guides the laser pulse emitted from the laser head; and an emission end unit which includes a compressor that compresses the laser pulse emitted from the optical fiber to a laser pulse of a predetermined high peak power and emits the laser pulse compressed by the compressor to the target.

Abstract: There is disclosed an apparatus for femtosecond laser optically pumped by a laser diode pumping module that is able to mechanically couple optical mounts for mounting optical mounts to each other by using a bar with a low thermal expansion coefficient and to form a light pumping module distant from a laser platform or a case, to provide a stable mode locking for an ultrashort laser and to enhance a power stability and a beam stability.

Abstract: The present invention relates to a high-power femtosecond pulsed laser, the laser including: a source able to generate a train of input laser pulses having an envelope frequency and a carrier frequency; a chirped pulse amplification unit; and, a unit for controlling the phase drift between the envelope frequency and the carrier frequency of the output laser pulses. According to the invention, the unit for controlling the phase drift between the envelope frequency and the carrier frequency includes electro-optical phase-modulation unit that are placed on an optical path of the chirped pulse amplification unit in order to stabilize the phase drift between the envelope frequency and the carrier frequency of the output laser pulses as a function of time.

Abstract: A laser anti-reflection device includes a polarizing beam splitter, a ?/4 wave plate and an absorber disposed in an outgoing light path of a laser emitting linearly polarized light with a wavelength of ?. The linearly polarized light from the laser passes through the polarizing beam splitter and the ?/4 wave plate in turn to become a circularly polarized light beam. Part of the circularly polarized light beam is then reflected by a workpiece to be processed along the original light path and passes the ?/4 wave plate to become a linearly polarized light beam with a polarization direction vertical to that of the outgoing linearly polarized light beam. The vertical polarized beam passes the polarizing beam splitter, deviates from the light path of the outgoing linearly polarized light beam and reaches the absorber. The laser anti-reflection device prevents reflected light from damaging the laser from high power lasers.

Abstract: A laser processing apparatus includes a laser beam generating device that generates a first pulse laser beam for temporarily increasing a light absorptance in a predetermined region of a processing object, and a second pulse laser beam to be absorbed in the predetermined region in which the light absorptance has temporarily increased, and a support portion that is provided on a downstream of the first pulse laser beam and the second laser beam generated by the laser beam generating device and has a placement surface for placing the processing object. The laser beam generating device emits the second pulse laser beam with a delay with respect to the first pulse laser beam by a delay time within a predetermined period of time before the light absorptance that has temporarily increased in the predetermined region returns to an original value.

Abstract: Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

Abstract: A laser amplifier includes an input aperture operable to receive laser radiation having a first polarization, an output aperture coupled to the input aperture by an optical path, and a polarizer disposed along an optical path. A transmission axis of the polarizer is aligned with the first polarization. The laser amplifier also includes n optical switch disposed along the optical path. The optical switch is operable to pass the laser radiation when operated in a first state and to reflect the laser radiation when operated in a second state. The laser amplifier further includes an optical gain element disposed along the optical path and a polarization rotation device disposed along the optical path.

Abstract: Described herein is a laser (1) having a cavity for supporting oscillation of an electromagnetic signal to provide lasing action. A gain element (5) provides a source of stimulated emission for amplifying the oscillating signal. The laser also includes a wavelength selective element (7), which includes a reflecting element and a polarization modifying element. The reflecting element selectively defines a predetermined wavelength and the polarization modifying element selectively modifies the polarization of the signal component at the predetermined wavelength so as to provide high selectivity. The wavelength selective element (7) rotates the signal polarization at the predetermined wavelength into an orthogonal state. A polarization filter (9) filters out the signal components having wavelengths not corresponding to the predetermined wavelength and a polarization rotation element (11) again rotates the polarization of the signal into an orthogonal state.

Abstract: Embodiments of the invention describe integrating a phase shifting component into a cavity of a laser. Said phase shifter is capable of a continuous phase shift at a single wavelength over a large range (where the maximum energy consumption of the phase shifting component does not scale with the phase shifting range). In other words, said phase shifter is used to form a configurable optical cavity length for a laser. Embodiments of the invention thus utilize a plurality of optical cavity lengths—including one or more optical cavity lengths to potentially shift the phase of the output optical signal, to maintain a laser cavity's output wavelength and avoid spatial mode-hops in the presence of fluctuations such as temperature drift or changes to the drive current of the laser.

Abstract: In the conventional contaminant particle/defect inspection method, if the illuminance of the illumination beam is held at not more than a predetermined upper limit value not to give thermal damage to the sample, the detection sensitivity and the inspection speed being in the tradeoff relation with each other, it is very difficult to improve one of the detection sensitivity and the inspection speed without sacrificing the other or improve both at the same time. The invention provides an improved optical inspection method and an improved optical inspection apparatus, in which a pulse laser is used as a light source, and a laser beam flux is split into a plurality of laser beam fluxes which are given different time delay to form a plurality of illumination spots. The scattered light signal from each illumination spot is isolated and detected by using a light emission start timing signal for each illumination spot.

Abstract: A mode-locked laser system operable at low temperature can include an annealed, frequency-conversion crystal and a housing to maintain an annealed condition of the crystal during standard operation at the low temperature. In one embodiment, the crystal can have an increased length. First beam shaping optics can be configured to focus a beam from a light source to an elliptical cross section at a beam waist located in or proximate to the crystal. A harmonic separation block can divide an output from the crystal into beams of different frequencies separated in space. In one embodiment, the mode-locked laser system can further include second beam shaping optics configured to convert an elliptical cross section of the desired frequency beam into a beam with a desired aspect ratio, such as a circular cross section.

Abstract: A tiled Bragg grating (BG) includes a plurality of BGs that are paralleled and optically contacted to one another. Each BG includes an optically transparent substrate within a predetermined wavelength or wavelength range having a length dimension and a transverse dimension. The BGs have a grating period along their length dimension. The BGs have optical contact regions along edges in their transverse dimension where the BGs are optically contacted to one another.

Abstract: The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.

Abstract: A master oscillator power amplifier (MOPA) system includes an oscillator having a neodymium-doped gadolinium vanadate gain-medium and delivering seed-pulses. A length of single mode fiber is used to broaden the spectrum of the seed pulse. An amplifier having a neodymium-doped yttrium vanadate gain-medium amplifies the spectrally broadened seed-pulses. The gain-spectrum of the amplifier partially overlaps the broadened pulse-spectrum, providing spectral selection of the seed-pulses in addition to amplification. This provides amplified output-pulses having a duration about one-third that of the corresponding seed-pulses.