Abstract: A method for setting a pluggable optical transceiver, includes: amplifying, with an amplifier, an electrical signal being input to the pluggable optical transceiver from an external device to which the pluggable optical transceiver is mounted, and outputting the amplified electrical signal as a drive signal of an optical modulator; modulating light input from a light source with the optical modulator, based on the drive signal, and outputting the modulated light; monitoring amplitude of the drive signal; and executing a control sequence being set in advance for at least one of the amplifier and the optical modulator when detecting that amplitude of the drive signal exceeds a reference value being set in advance.

Abstract: Techniques are disclosed relating to level-shifting circuitry and time borrowing across voltage domains. In some embodiments, sense amplifier circuitry generates, based on an input signal at a first voltage level, an output signal at a second, different voltage level. Pulse circuitry may generate a pulse signal in response to an active clock edge of a clock signal that is input to the sense amplifier circuitry. Initial resolution circuitry may drive the output signal of the sense amplifier circuitry to match the value of the input signal during the pulse signal. Secondary resolution circuitry may maintain a current value of the output signal after expiration of the pulse signal. This may allow the input signal to change during the pulse, e.g., to enable time borrowing by upstream circuitry.

Abstract: A method of controlling output of a radiation source, the method including: periodically monitoring an output energy of the radiation source; determining a difference between a reference energy signal and the monitored output energy; determining a feedback value; determining a desired output energy of the radiation source for a subsequent time period; and controlling an input parameter of the radiation source in dependence on the determined desired output energy during the subsequent time period. If the magnitude of the determined difference between the monitored output energy of the radiation source and the reference energy signal exceeds a threshold value: the determined difference does not contribute to the feedback value; and the determined difference is spread over the subsequent time period according to a reference energy signal adjustment profile and the reference energy signal adjustment profile is added to the reference energy signal for the subsequent time period.

Abstract: An example system includes capture circuitry to obtain first parametric data based on a first signal at an interface to a first communication channel, with the first parametric data representing non-informational content of the first signal; and control circuitry to receive the first parametric data and to provide second parametric data, the second parametric data being based on one or both of: the first parametric data or a programmatic input. The example system also includes interface circuitry to receive the second parametric data and to receive informational content data representing informational content, and to process the informational content data and the second parametric data to produce a second signal. The second signal has the informational content represented by the informational content data and having at least some non-informational content based on the second parametric data.

Abstract: A line-narrowed KrF excimer laser apparatus includes a laser chamber, a line narrow optical system, an actuator, an output coupling mirror, a wavelength detecting unit, and a wavelength controller. The actuator is capable of changing a wavelength of light selected by the line narrow optical system. The wavelength detecting unit includes a low-pressure mercury lamp accommodating mercury, a getter material that adsorbs at least a part of the mercury, and a hot cathode that excites at least a part of the mercury, an etalon provided at a position where reference light emitted from the low-pressure mercury lamp and detected light emitted from the output coupling mirror are incident on the etalon, and a light intensity distribution sensor configured to detect an intensity distribution profile of interference fringes of the reference light and an intensity distribution profile of interference fringes of the detected light.

Abstract: A laser beam machine includes a number of laser modules that each generate a laser beam and a combiner that collects a plurality of laser beams generated from the laser modules to output one laser beam. The laser beam machine further includes a plurality of driving power supplies that supply power to the laser modules, respectively, a calculation device that calculates a driving condition for each of the laser modules according to a received machining condition, and a power-supply control apparatus that causes the driving power supplies to supply power to the laser modules in accordance with the driving condition. The calculation device controls the power-supply control apparatus to reduce differences in integrated laser-output times of the laser beams generated by the laser modules.

Abstract: Laser safety systems, devices, and methods for use in laser projectors are described. A laser projector includes any number of laser diodes that each emit laser light, a laser diode power source, a current sensor to detect a magnitude of the electric current output by the power source, a photodetector to detect a power/intensity of the laser light, a beam splitter to direct a first portion of the light towards the photodetector and a second portion of the light towards an output on the projector, and first and second laser safety circuits responsive to signals from the photodetector and the current sensor, respectively. The laser safety circuits selectively electrically couples/uncouples the laser diodes from the power source depending on signals from the photodetector and/or the current sensor. Particular applications of the laser safety systems, devices, and methods in a wearable heads-up display are described.

Abstract: Laser safety systems, devices, and methods for use in laser projectors are described. A laser projector includes any number of laser diodes that each emit laser light, a laser diode power source, a current sensor to detect a magnitude of the electric current output by the power source, a photodetector to detect a power/intensity of the laser light, a beam splitter to direct a first portion of the light towards the photodetector and a second portion of the light towards an output on the projector, and first and second laser safety circuits responsive to signals from the photodetector and the current sensor, respectively. The laser safety circuits selectively electrically couples/uncouples the laser diodes from the power source depending on signals from the photodetector and/or the current sensor. Particular applications of the laser safety systems, devices, and methods in a wearable heads-up display are described.

Abstract: Laser safety systems, devices, and methods for use in laser projectors are described. A laser projector includes any number of laser diodes that each emit laser light, a laser diode power source, a current sensor to detect a magnitude of the electric current output by the power source, a photodetector to detect a power/intensity of the laser light, a beam splitter to direct a first portion of the light towards the photodetector and a second portion of the light towards an output on the projector, and first and second laser safety circuits responsive to signals from the photodetector and the current sensor, respectively. The laser safety circuits selectively electrically couples/uncouples the laser diodes from the power source depending on signals from the photodetector and/or the current sensor. Particular applications of the laser safety systems, devices, and methods in a wearable heads-up display are described.

Abstract: An optical system can lock a wavelength of a tunable laser to a specified wavelength of a temperature-insensitive spectral profile of a spectral filter. In some examples, the spectral filter, such as a Fabry-Perot filter, can have a temperature-insensitive peak wavelength and increasing attenuation at wavelengths away from the peak wavelength. The spectral filter can spectrally filter the laser light to form filtered laser light. A detector can detect at least a fraction of the filtered laser light. Circuitry coupled to the detector and the laser can tune the tunable laser to set a signal from the detector to a specified value corresponding to a specified wavelength in the spectral profile, and thereby adjust the selectable wavelength of the tunable laser to match the specified wavelength. In some examples, the optical system can include a polarization rotator, and can use polarization to separate incident light from return light.

Abstract: A laser apparatus may include: an optical amplifier configured to amplify a laser beam outputted from a master oscillator; an optical-amplifier power supply configured to supply an alternating current for optical amplification to the optical amplifier; and a laser controller. The optical-amplifier power supply may include: an alternating current generation circuit including an inverter circuit configured to change output amplitude in accordance with a duty cycle, the alternating current generation circuit being configured to generate the alternating current from an output of the inverter circuit; and a power supply control circuit configured to hold control information defining correspondence relations between command values from the laser controller and duty cycles of the inverter circuit, determine a duty cycle corresponding to a command value received from the laser controller based on the control information, and provide the determined duty cycle to the inverter circuit.

Abstract: A beam scanning device includes a variable-wavelength laser that emits a laser beam, a plane-wave converting unit that converts the laser beam into a plane-wave laser beam, a light-intensity-distribution converting unit including a first light-intensity-distribution converting unit set to be obliquely tilted with respect to an emitting direction of the laser beam within a horizontal plane and a second light-intensity-distribution converting unit set to be obliquely tilted with respect to the emitting direction of the laser beam within a plane perpendicular to the horizontal plane and parallel to the emitting direction of the laser beam, the light-intensity-distribution converting unit converting a peak position of light intensity of the plane-wave laser beam according to a wavelength of the plane-wave laser beam, and a spherical-wave converting unit that converts the plane-wave laser beam, the peak position of the light intensity of which is converted, into a spherical-wave laser beam.

Abstract: A device capable of measuring one or more degrees of freedom with respect to a beam of light is described. The angle of rotation around the beam is obtained with a polarized beam of light and a polarizing optic and a sensor. A control system holds a sensor reading to a predetermined value. Therefore as the device is rotated around the beam, the optic will be rotated to maintain the sensor reading and an encoder provides the measurement of the amount of rotation. A position sensing device provides transverse information about the location of the beam and rotation of the device around two other axes. A second position sensing device at a difference distance from the light transmitter allows for the separation of transverse and rotational measurements. Alternately, the transverse measurement can be obtained by a light transmitter capable of making the measurement on a reflected beam.

Abstract: The present invention provides a gas measuring method based on photothermal effect in hollow-core optical fiber comprising: filling a target gas into the core of a hollow-core optical fiber; coupling a probe light and a periodically modulated pump light into the hollow-core optical fiber; absorbing the pump light by the target gas resulting in the periodic modulation of the phase of the probe light; demodulating the phase modulation information of the probe light to obtain the concentration of the target gas, wherein the pump laser is wavelength and/or amplitude modulated. In the present invention, two lasers including a pump laser and a probe laser are used for the measurement, this approach is simple and practical.

Abstract: There is provided a power control method for a fiber laser processing machine including: a fiber laser oscillator having a plurality of fiber laser modules each of which generates a laser beam; a laser processing head for emitting the laser beam generated from the fiber laser oscillator; and a condenser lens with a prescribed focal length provided between a workpiece and the laser processing head, for irradiating the workpiece with the laser beam having a spot diameter output from the laser processing head, wherein the number of the plurality of fiber laser modules oscillated is adjusted so as to achieve the spot diameter corresponding to the workpiece, and thereby, a beam quality from the laser processing head is adjusted.

Abstract: An image forming apparatus incudes a driving unit configured to drive a light-emitting element for emitting a laser beam; a rotational polygon mirror scans a photosensitive member with the laser beam. The driving unit executes a first adjustment for causing the light-emitting element to emit light at a first light emission intensity to adjust a first driving current, and a second adjustment for causing the light-emitting element to emit light at a second light emission intensity to adjust a second driving current. During a time period after the polygon mirror has started rotating until a predetermined speed is reached, the driving unit performs the first adjustment and the second adjustment, after the polygon mirror has started rotating and before performing the first adjustment, performs the second adjustment.

Abstract: An optical system includes a device selected from a transmitter and a receiver. The transmitter has multiple laser cavities that each generates an optical channel at a different channel wavelength. The transmitter is also configured to modulate the optical channels into modulated light signals. The receiver is configured to demultiplex modulated light signals and use the demultiplexed light signals to generate electrical signals. The device is configured to operate in an atmosphere having an operational temperature range that includes a range of temperatures extending from TL to TH. Electronics are configured to elevate the temperature of the device when the temperature of the atmosphere is in a first portion of the temperature range from TL to TH but not elevate the temperature of the controlled device when the temperature of the atmosphere is in a second portion of the temperature range from TL to TH.

Abstract: An opto-isolator is disclosed that include a vertical cavity surface emitting laser (VCSEL), a photodetector and a package enclosing the VCSEL and the photodetector. The photodetector is optically coupled to the VCSEL and configured to receive an output optical signal generated by the VCSEL.

Abstract: In a semiconductor light-emitting element, a first cladding layer in a first conductive type, a quantum well active layer, and a second cladding layer in a second conductive type are stacked on a semiconductor substrate in this order. A ridge-shaped stripe formed at the second cladding layer forms a waveguide. Rf<Rr and Wf>Wr are satisfied, where the width of the ridge-shaped stripe at a front end face from which laser light is output is represented by Wf, the width of the ridge-shaped stripe at a rear end face is represented by Wr, the reflectance of the front end face is represented by Rf, and the reflectance of the rear end face is represented by Rr. Light in a fundamental transverse mode, a first high-order transverse mode, a second high-order transverse mode, and a third high-order transverse mode is guided in the waveguide.

Abstract: Systems and methods are disclosed herein for controlling laser beams for a plurality of collocated laser assemblies. The laser beams are optimized by controlling outputs of a primary power source (current for generating a laser beam) and a secondary power source (heating device) for each of the respective laser assemblies. The states of the power supply may be cycled and modulated to provide optimal performance.

Abstract: A method is disclosed for power normalization of spectroscopic signatures obtained from laser based chemical sensors that employs the compliance voltage across a quantum cascade laser device within an external cavity laser. The method obviates the need for a dedicated optical detector used specifically for power normalization purposes. A method is also disclosed that employs the compliance voltage developed across the laser device within an external cavity semiconductor laser to power-stabilize the laser mode of the semiconductor laser by adjusting drive current to the laser such that the output optical power from the external cavity semiconductor laser remains constant.

Abstract: A power monitoring and correction to a desired power level of a laser or group of lasers utilizes two photodetectors which are employed to accurately determine the amount of output power from the front end or “customer” end of a laser or a plurality of such lasers. During power detection, which may be accomplished intermittently or continuously, the laser is modulated with a tone of low frequency modulation. One photodetector at the rear of the laser is employed to detect the DC value of the frequency tone, i.e., a value or number representative of the AC peak-to-peak swing, amplitude or modulation depth of the tone. Also, the rear photodetector may be employed to determine the optical modulation index (OMI). In either case, these values may be employed in a closed loop feedback system to adjust or otherwise calibrate the value of the low tone frequency relative to the total desired bias current applied to the laser.

Abstract: A laser system for semiconductor inspection includes a fiber-based fundamental light source for generating fundamental light that is then converted/mixed by a frequency conversion module to generate UV-DUV laser light. The fundamental light source includes a nonlinear chirp element (e.g., a Bragg grating or an electro-optic modulator) that adds a nonlinear chirp to the seed light laser system prior to amplification by the fiber amplifier(s) (e.g., doped fiber or Raman amplifiers). The nonlinear chirp includes an x2 or higher nonlinearity and is configured to compensate for the Self Phase Modulation (SPM) characteristics of the fiber-based amplifiers such that fundamental light is generated that has a spectral E95 bandwidth within five times that of the seed light. When multiple series-connected amplifiers are used, either a single nonlinear chirp element is provided before the amplifier string, or chirp elements are included before each amplifier.

Abstract: A semiconductor laser has an optical cavity comprising and active layer disposed between an n-side barrier layer and a p-side barrier layer. The active layer comprises alternating layers of a first and second material, and the n-side barrier layer and p-side barrier layer each comprise alternating layers of the first material and a third material. The materials are selected such that the layers of the second and third materials form quantum wells between the layers of the first material. A band gap Eg of the second material is arranged such that a proportion of electrons and holes that recombine across the band gap Eg recombine to emit photons at the lasing wavelength, the proportion decreasing with increasing temperature of the optical cavity.

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 gas laser oscillator, including a power supply part supplying a discharge tube voltage corresponding to a power output command to a discharge tube so as to start a discharge in the discharge tube; a voltage detecting part detecting the discharge tube voltage; a current detecting part detecting an output current of the power supply part; a command voltage control part gradually increasing a power output command value output from the output command part; and a discharge start judgment part judging if the discharge in the discharge tube has started, based on a detected value of the voltage detecting part when gradually increasing the power output command value. The command voltage control part, if the output current becomes a predetermined threshold value or more when gradually increasing the power output command value, decreases the power output command value once, then again gradually increases the power output command value.

Abstract: The presently disclosed technique presents laser-based method and apparatus for use in remote sensing. In general, objects within a field of view are lased by a long cavity laser apparatus. Returns are detected, captured, and processed to identify actual objects of interest. These can then be communicated to a user. Over time, the actual objects of interest can be auto-tracked.

Abstract: A method to tune an emission wavelength of a wavelength tunable LD is disclosed. The wavelength tunable LD includes two regions each providing micro heaters to modify the refractive index of micro regions provided with power. The method periodically detects a difference between the emission wavelength and the target wavelength. This wavelength difference is converted into power next supplied to respective micro heaters independently.

Abstract: In a method, a gain medium is provided having an absorption coefficient that varies with wavelength. An absorption coefficient curve of the absorption coefficient or a range of wavelengths comprises peaks and valleys. A pump module is operated to output pump energy at an operating wavelength within one of the valleys, at which the absorption coefficient is approximately less than 40% of the absorption coefficient at an adjacent peak of the absorption coefficient curve defining the valley. The pump energy is directed through the gain medium. A portion of the pump energy is absorbed with the gain medium and laser light is emitted from the gain medium responsive to the absorbed pump energy. The non-absorbed pump energy (feedback pump energy) is fed back to the pump module. The operating wavelength of the pump energy is stabilized using the feedback pump energy.

Abstract: A method or algorithm to control a driving current supplied to a semiconductor laser diode (LD) is disclosed. the method first prepares the look-up-table (LUT) that stores a set of parameters, ? and ?, for evaluating the modulation current Im by the equation of Im=?×Ib+?, where Ib is determined by the auto-power-control (APC) loop. In a practical operation of the LD, the APC loop determines Ib, while, Im is calculated according to the equation above by reading above two parameters corresponding to the current temperature of the LD from the LUT.

Abstract: A laser machining control system includes a laser diode, a laser power controller connected to the laser diode, a light transmission-reflection element positioned on a light path of a laser light beam to a workpiece, and an output power meter. The output power meter detects the laser light beam being reflected by the transmission-reflection element and measures an output power of the laser diode. The output power meter gives a signal to the laser power controller if there is a power loss of the laser light beam, and the laser power controller adjusts the voltage and the current input to the laser diode in compensation.

Abstract: A diode laser assembly including a plurality of diode bars disposed on a generally flat base plate and being oriented to emit a plurality of laser beams in a first direction. A reflector is spaced in the first direction from each of the diode bars in the first. Each reflector has at least two reflecting surfaces, one for reflecting the laser beams into a second direction different from the first direction and the other for reflecting the laser beams into a third direction different from the first and second directions to produce a spatially combined laser beam. Each reflector is moveable relative to one another and to the diode bars for adjusting the individual laser beams within the spatially-combined laser beam for optimizing the quality of the spatially combined laser beam.

Abstract: An optical power stabilizing device is adapted to stabilize optical power of a light emitting device having a forward voltage, and includes a current generating circuit that generates a pulse-wave driving current to drive light emission of the light emitting device, an optical-type feedback circuit that outputs a first feedback voltage according to detected optical power of the light emitting device, an electrical-type feedback circuit that outputs a second feedback voltage according to the forward voltage, and a pulse wave generating circuit that generates a pulse-wave signal to control the current generating circuit according to one of the first feedback voltage and the second feedback voltage.

Abstract: A laser processing apparatus, a filter device and a method are used for controlling a pulse laser, which is controllable in terms of its pulse energy and of a temporal triggering of laser pulses, during material processing of an object, in particular during the marking of a plastics-based document. The method includes comparing a pulse energy signal which assumes voltage values, in temporal correlation with a clock signal, which represent a pulse energy for the laser pulses for processing, with a threshold value condition and generating a logic result signal. The clock signal is passed to a gate and controlling the gate using the logic result signal and generating a retrieval signal thereby. An energy control signal is provided which has a voltage according to a specification of a control voltage. The retrieval signal and the energy control signal are used to control the pulse laser.

Abstract: There is provided a wavelength variable light source system capable of changing wavelength and intensity of output signal light and of improving preset accuracy and stability of the wavelength and strength of the output signal light. The system determines the both or either one of a target value for controlling wavelength and a target value for controlling intensity of output signal light of a wavelength variable light source by correlating a combination of the target wavelength and the target light output intensity specified from a higher-level device and controls operation states of the wavelength variable light source so that output values of monitoring circuits for monitoring the operation state of the wavelength variable light source converge to the target values.

Abstract: A carbon-dioxide CO2 gas-discharge laser is energized by the output a radio-frequency power supply (RFPS). Output-power of the laser is stabilized by adjustments of the RFPS responsive to periodic measurements of the laser output-power using detector output amplified by an amplifier. The amplifier has an offset-voltage which is subject to drift. A synchronous auto-zero arrangement is provided for canceling out the offset-voltage of the amplifier immediately prior to each periodic measurement of the laser output power.

Abstract: Semiconductor light-emitting devices; methods of forming semi-conductor light emitting devices, and methods of operating semi-conductor light emitting devices are provided. A semiconductor light-emitting device includes a first laser section monolithically integrated with a second laser section on a common substrate. Each laser section has a phase section, a gain section and at least one distributed Bragg reflector (DBR) structure. The first laser section and the second laser section are optically coupled to permit optical feedback therebetween. Each phase section is configured to independently tune a respective one of the first laser section and second laser section relative to each other.

Abstract: A laser driver apparatus, system, and method include a single laser driver. One or more threshold levels and one or more undershoot levels can be digitally combined into a single output with respect to the single laser driver to reduce the output capacitance of the single laser driver and minimize circuit power, resulting in a faster and higher fidelity signal thereof. A decoder (e.g., thermometer decoding) can also be provided, wherein the threshold level(s) and the undershoot level(s) are thermometer decoded via the decoder.

Abstract: It is an object of the invention to simplify the power stabilization of laser diodes. For this purpose, a laser device comprising a die and thereon a first laser diode and a second laser diode is provided. The second laser diode has a structure or element that avoids lasing if a supply voltage is applied that is sufficient for the first semiconductor laser cavity to emit laser light.

Abstract: A projection apparatus includes at least one laser diode and a laser diode junction temperature estimator to estimate the junction temperature of the at least one laser diode. Laser diode current drive values are modified in response to the estimated laser junction temperature. The modification of laser diode current drive values may occur as frequently as once per pixel.

Abstract: Provided is a method for controlling a laser oscillator. Such a laser oscillator is applicable to a laser processing machine and includes a plurality of oscillator modules each adapted to be driven to oscillate a laser beam. Also, such a laser oscillator is configured to collect laser beams oscillated by driven modules for output. The method includes determining the number of modules to be driven, of the plurality of oscillator modules.

Abstract: Techniques and devices for generating laser light that use large mode area fiber amplifiers and curved fiber sections to achieve desired operations in a fundamental fiber mode with high pulse quality and optical beam quality while reducing presence of high order fiber modes in continuous wave and pulsed laser devices.

Abstract: An optical information record/playback device of the present invention includes: a light source; a current driver for supplying current to the light source; an optical system for condensing light from the light source onto a recording medium; a monitoring section for monitoring light emission power of the light source; a current driver control section for controlling output current of the current driver; and an arithmetic/control section for controlling an operation of the current driver control section. Before recording information, the arithmetic/control section sequentially conducts a first test light-emission to cause the light source to emit light by using a closed loop circuit and a second test light-emission to cause the light source to emit light by using an open loop circuit, and compares first and second sampling values, which are respectively obtained by sampling the outputs of the monitoring section during the first and second test light-emissions.

Abstract: A multi-beam laser device is used to make a microretarder plate, which comprises a plurality of first retardation state areas and second retardation state areas alternating with each other. The device comprises an infrared laser, a beam splitter, and a driving means. The beam splitter is used to split the laser beam into a plurality of equal intensity parallel beams and bring the parallel beams into focus. The driving mechanism is used to drive the beam splitter in one direction, and the beam splitter will scan a plurality of parallel scan lines by the direction on a surface.

Abstract: A system for equalizing pulse to pulse energy of a light beam includes a group of optical devices including an optical device configured to exhibit nonlinear properties, e.g., higher order or third order nonlinear properties. Transmission properties of an unequalized light beam passing through the group of optical devices change such that an output intensity of a resulting light beam output from the optical devices is equalized. One example configuration includes at least first and second prisms having nonlinear properties, i.e., higher order or third order, and configured as a beam steering system.

Abstract: A method is disclosed for power normalization of spectroscopic signatures obtained from laser based chemical sensors that employs the compliance voltage across a quantum cascade laser device within an external cavity laser. The method obviates the need for a dedicated optical detector used specifically for power normalization purposes. A method is also disclosed that employs the compliance voltage developed across the laser device within an external cavity semiconductor laser to power-stabilize the laser mode of the semiconductor laser by adjusting drive current to the laser such that the output optical power from the external cavity semiconductor laser remains constant.

Abstract: The present invention provides a laser beam control apparatus including: beam optical systems 33 and 34 for dividing a laser beam into a principal beam P and an auxiliary beam S and then for crossing the principal beam P and the auxiliary beam S; polarizing devices 36 and 37 for converting the laser beam before the division process into a linearly-polarized beam or converting the laser beams after the division process into linearly-polarized beams; a polarization direction change element 38 for changing the polarization direction of either one or both of the principal beam P and the auxiliary beam S; an optical gate element 35 provided at the intersection of the principal beam P and the auxiliary beam S and made of a material that exhibits the optical Kerr effect; and a polarization filter 39 for taking out from the principal beam P which has passed through the optical gate element 35 only a beam polarized in a predetermined direction.

Abstract: A controller for controlling the power of a laser that is used in determining the motion of an object includes a power source that is arranged to supply power pulses to the laser in response to a controller signal. The controller controls the generation of pulses during periods in which a reliable result can be obtained, by detecting the laser radiation that has interacted with pulses reflected from the object, in order to conserve power consumption. Further the power pulses include a heating pulse portion, which serves to stabilize the temperature of the laser and calibrate the laser so that a known lasing wavelength is generated.

Abstract: Disclosed herein is a method and apparatus for automatic correction of beam waist position drift in real time, using wafer inspection data taken during normal tool operation. Also disclosed herein is an improved laser astigmatism corrector for use either internal or external to the laser.

Abstract: A wavelength conversion laser light source includes an element temperature switching section that switches a temperature of the wavelength conversion element according to a harmonic wave output value as set in an output setting device, and the element temperature switching section for switching a temperature of a wavelength conversion element according to a harmonic wave output level as set in the output setting device. The element temperature switch section includes an element temperature holding section that holds the wavelength conversion element at the temperature as switched by the element temperature switching section.