Abstract: A carbon dioxide gas-discharge slab-laser is assembled in a laser-housing. The laser-housing is formed from a hollow extrusion. An interior surface of the extrusion provides a ground electrode of the laser. Another live electrode is located within the extrusion, electrically insulated from and parallel to the ground electrode, forming a discharge-gap of the slab-laser. The electrodes are spaced apart by parallel ceramic strips. Neither the extrusion, nor the live electrode, include fluid coolant channels. The laser-housing is cooled by fluid-cooled plates attached to the outside thereof.

Abstract: Laser annealing apparatus includes a plurality of frequency-tripled solid-state lasers, each delivering an output beam of radiation at a wavelength between 340 nm and 360 nm. Each output beam has a beam-quality factor (M2) greater of than 50 in one transverse axis and greater than 20 in another transverse axis. The output beams are combined and formed into a line-beam that is projected on a substrate being annealed. Each output beam contributes to the length of the line-beam.

Abstract: An apparatus for cutting brittle material comprises an aspheric focusing lens, an aperture, and a laser-source generating a beam of pulsed laser-radiation. The aspheric lens and the aperture form the beam of pulsed laser-radiation into an elongated focus having a uniform intensity distribution along the optical axis of the aspheric focusing lens. The elongated focus extends through the full thickness of a workpiece made of a brittle material. The workpiece is cut by tracing the optical axis along a cutting line. Each pulse or burst of pulsed laser-radiation creates an extended defect through the full thickness of the workpiece.

Abstract: An anamorphic three-element objective lens projects a plurality of beams of different wavelengths and different diameters into an elongated focal spot in a working-plane. In one transverse direction of the lens, the beams are tightly focused with equal beam-waist widths in the working-plane, defining a height of the focal spot. In another transverse direction, the different beams are focused progressively beyond the working-plane such that the beams have a common beam-width in the working-plane, thereby defining a width of the focal spot.

Abstract: Extracting a displacement component includes: receiving a received signal resulting from an optical signal being scattered by the plurality of particles in the fluid, the received signal comprising a displacement component; mixing the received signal with a local oscillator signal to generate a mixed signal; detecting the mixed signal via a set of one or more detectors and generating a set of one or more electrical signals based on the detection; demodulating the set of one or more electrical signals to obtain the displacement component; and outputting the displacement component.

Abstract: A carbon dioxide gas-discharge slab-laser is assembled in a laser-housing. The laser-housing is formed from a hollow extrusion. An interior surface of the extrusion provides a ground electrode of the laser. Another live electrode is located within the extrusion, electrically insulated from and parallel to the ground electrode, forming a discharge-gap of the slab-laser. The electrodes are spaced apart by parallel ceramic strips. Neither the extrusion, nor the live electrode, include any direct fluid-cooling means. The laser-housing is cooled by fluid-cooled plates attached to the outside thereof.

Abstract: An apparatus for generating visible light including a laser source emitting a fundamental beam, an optically nonlinear crystal, and a seed source emitting a seed beam. The optically nonlinear crystal receives the fundamental beam. The fundamental beam propagates in the nonlinear crystal at a first phase-matching angle for second-harmonic generation. A portion of the fundamental beam is converted into a second-harmonic beam that propagates in the nonlinear crystal at the first phase-matching angle for optical parametric generation. The seed source emits a seed beam having a wavelength longer than the second-harmonic beam. The seed beam is directed into the nonlinear crystal and propagates at a second phase-matching angle for the optical parametric amplification. A portion of the second-harmonic beam is converted into a signal beam at the seed wavelength and an idler beam by the optical parametric amplification.

Abstract: A third-harmonic conversion arrangement includes a second-harmonic generating crystal and a third-harmonic generating crystal arranged in a polarization loop. The polarization loop causes plane-polarized fundamental-wavelength radiation being converted to make two passes through the crystals in orthogonally-opposed polarization orientations.

Abstract: Optical output beams from a vertical stack of diode-laser bars are focused by a simple focusing lens on an optical axis of the lens. The optical output beams from outlying diode-laser bars in the vertical stack are tilted with respect to the optical axis of the focusing lens such that optical output from the whole vertical stack is brought to a common focus location on the optical axis of the focusing lens.

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: A laser master-oscillator power-amplifier (MOPA) is operated to provide successive bursts of ultrashort pulses. The pulse-bursts are selected by an optical modulator from a pulse train delivered by the master oscillator prior to amplification in the power amplifier. The optical modulator has a selectively variable transmission specified by an analog voltage signal having a stepped waveform. The voltage signal is delivered by a sequentially-switched parallel switch-array connected in parallel with a parallel DAC having multiple parallel DC voltage outputs corresponding to steps of the stepped waveform.

Abstract: A method of delivering a beam of laser-radiation to a workpiece for processing the workpiece comprises transmitting the beam twice through an inactive acousto-optic modulator (AOM) crystal in opposite zero-order directions of the AOM at separate locations on the AOM crystal, before delivering the beam to the workpiece. When laser-radiation is to be blocked from reaching the workpiece, the AOM is activated.

Abstract: An aluminum covered with an anodically formed aluminum oxide layer is marked by repeated bursts of two or more individual laser pulses. The intensity of the individual pulses in the bursts is kept below a level experimentally determined to compromise the integrity of the aluminum oxide layer. The collective fluence in a burst is sufficient to mark the aluminum, but not sufficient to compromise the integrity of the oxide layer.

Abstract: A diode-laser assembly having an electrically isolated diode-laser bar on a cooled base-element is disclosed. The diode-laser bar is electrically isolated from the base-element and electrically isolated from any coolant water, thereby eliminating the need for de-ionized water and mitigating corrosion due to galvanic action. Multiple such diode-laser assemblies are stackable, with small bar-to-bar pitch, enabling a high-current and high-brightness diode-laser stack.

Abstract: Laser-drilling apparatus includes a gas-discharge for laser emitting laser-radiation pulses, and two acousto-optic modulators (AOMs). The laser radiation pulses are characterized as having two temporal central portions between temporal leading and trailing edge portions. The AOMs are arranged to spatially separate the central temporal portions of the pulses from each other and from the leading and trailing edge portions of the pulses.

Abstract: Systems and methods for material singulation. According to some embodiments, methods for material singulation may include applying a first laser output to the material, the first laser output causing a modification of a material property of the material when exposed to the first laser output; and applying a second laser output to the material that was exposed to the first laser output to cause singulation of the material in such a way that surfaces created by the singulation of the material are substantially free from defects.

Abstract: An intra-cavity frequency-tripled OPS laser has a laser-resonator including two optically nonlinear crystals arranged for type-I frequency conversion. One of the crystals generates horizontally polarized second-harmonic radiation from vertically plane-polarized fundamental-wavelength radiation circulating in the laser-resonator. A birefringent filter is located between the optically nonlinear crystals. The birefringent filter selects the fundamental-wavelength, establishes the vertical polarization-orientation, and selectively rotates the polarization-orientation of the second-harmonic radiation from horizontal to vertical. The vertically polarized fundamental and second-harmonic radiations are type-I sum-frequency mixed by the other optically nonlinear crystal.

Abstract: A housing for an optically pumped semiconductor (OPS) laser resonator is terminated at one end thereof by an OPS-chip. The laser resonator is assembled on a platform with the OPS-chip at one end of the platform. The platform is fixedly attached to a baseplate at the OPS-chip end of the platform. The remainder of the platform extends over the baseplate with a gap between the platform and the baseplate. A pump-laser is mounted directly on the baseplate and delivers pump radiation to the OPS-chip.

Abstract: A mirror is used to form a beam of laser-radiation having a uniform intensity distribution from a beam of laser-radiation having a non-uniform intensity distribution. The mirror has a reflective surface that has a compound shape, which is two inclined surfaces joined by a rounded apex. The compound-mirror is achromatic and can form a uniform intensity distribution from a polychromatic beam of laser-radiation. The uniform intensity distribution may be an isotropic distribution or a flat-top distribution in a plane. The non-uniform intensity distribution may be a Gaussian distribution from a laser source.

Abstract: A laser-radiation sensor includes a copper substrate on which is grown an oriented polycrystalline buffer layer surmounted by an oriented polycrystalline sensor-element of an anisotropic transverse thermoelectric material. An absorber layer, thermally connected to the sensor-element, is heated by laser-radiation to be measured and communicates the heat to the sensor-element, causing a thermal gradient across the sensor-element. Spaced-apart electrodes in electrical contact with the sensor-element sense a voltage corresponding to the thermal gradient as a measure of the incident laser-radiation power.