A method for laser welding a metal foil stack to a metal substrate includes clamping the foil stack against a support surface of a substrate and irradiating the stack with a beam of laser pulses to weld the foils to the substrate. The beam is a composite beam including a center beam and a surrounding annular beam. An initial series of the laser pulses are incident on the stack at mutually distinct locations on a top surface of the stack, and a subsequent series of the laser pulses are incident on the stack at mutually distinct locations on a side of the stack. The resulting weld nuggets penetrate deeply into the stack, with an average penetration depth that exceeds an average pitch between the weld nuggets. The method is capable of welding more than 100 foils to the substrate. Welded assemblies have been demonstrated to withstand large shear forces.
G02B 1/02 - Optical elements characterised by the material of which they are madeOptical coatings for optical elements made of crystals, e.g. rock-salt, semiconductors
F21V 8/00 - Use of light guides, e.g. fibre optic devices, in lighting devices or systems
A method laser cuts and laser pre-welds a stack of metal foils in a single laser process. The method includes clamping together the stack of metal foils, and irradiating the clamped stack with a laser beam to complete a cut through the entire stack and, while cutting the stack, form a weld joint joining the metal foils together at the cut. Subsequently, the cut and pre-welded stack of metal foils may be laser welded to a metal substrate that is significantly thicker than individual foils. The method may be applied to stacks of anode and cathode foils in electrochemical batteries, such as lithium-ion batteries.
A method for frequency conversion in a single-longitudinal-mode linear resonator includes frequency converting intracavity laser radiation in a nonlinear crystal disposed in a linear resonator. The intracavity laser radiation is in a single longitudinal mode of the resonator and forms a standing wave between its end-mirrors. The method also includes repeatedly sweeping the standing wave back and forth, along an optical axis of the resonator, relative to the nonlinear crystal. This repeated sweeping may be achieved by dithering the longitudinal position of (a) one or both of the end-mirrors or (b) the nonlinear crystal. Dithering of a single end-mirror may be driven by modulating a reference wavelength to which the wavelength of the intracavity laser radiation is locked. Dithering of the longitudinal position of the nonlinear crystal may be achieved with a piezoelectric actuator arranged to adjust angles of a parallelogram-shaped flexure to which the nonlinear crystal is mounted.
H01S 3/00 - Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
H01S 3/105 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity
H01S 3/109 - Frequency multiplication, e.g. harmonic generation
H01S 3/131 - Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the active medium, e.g. by controlling the processes or apparatus for excitation
A composite filter (100) includes a substrate (110) and, disposed thereon, a dielectric reststrahlen coating (120) and a dielectric coating stack (130). The substrate (110) is transmissive in a first infrared wavelength range from 9 to 11 micrometers as well as in neighboring infrared wavelength ranges above and below the first infrared wavelength range. The dielectric reststrahlen coating (120) has a reststrahlen band that overlaps with the first infrared wavelength range and contains at least one carbon dioxide laser wavelength, and is partly absorptive at the carbon dioxide wavelength(s). The dielectric coating stack (130) forms a multilayer interference filter that is predominantly reflective at the carbon dioxide laser wavelength(s) and predominantly transmissive in a second infrared wavelength range below the reststrahlen band.
A laser frequency conversion system with ultraviolet-damage mitigation includes a nonlinear crystal for frequency converting a laser beam, and a one-dimensional beam expander arranged to receive the laser beam from the nonlinear crystal and expand a first transverse dimension of the laser beam. This expansion protects subsequent optical elements from ultraviolet damage. To mitigate ultraviolet damage to the nonlinear crystal and the beam expander, the system also includes one or more translation stages configured to translate the nonlinear crystal and the beam expander along a translation direction that is orthogonal to the first transverse dimension of the laser beam and non-parallel to a propagation direction of the laser beam through the nonlinear crystal and the beam expander.
A Q-switched gas laser apparatus with bivariate pulse equalization includes a gas laser, a sensor, and an electronic circuit. A Q-switch that switches the laser resonator between high-loss and low-loss states to generate a pulsed laser beam. The sensor obtains a measurement of the pulsed laser beam indicative of the laser pulse energy. The electronic circuitry operates the Q-switch to (a) repeatedly switch the laser resonator between the high-loss and low-loss states to set a repetition rate of laser pulses of the pulsed laser beam, (b) adjust a loss level of the low-loss state, based on the pulse energy measurement, to achieve a target laser pulse energy, and (c) adjust a duration of the low-loss state to achieve a target laser pulse duration. By adjusting both pulse energy and duration, uniform pulse energy and, if desired, uniform pulse duration are achieved over a wide range of repetition rates.
H01S 3/223 - Gases the active gas being polyatomic, i.e. containing two or more atoms
H01S 3/117 - Q-switching using intracavity acousto-optic devices
H01S 3/13 - Stabilisation of laser output parameters, e.g. frequency or amplitude
H01S 3/136 - Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling devices placed within the cavity
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/106 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
H01S 3/23 - Arrangement of two or more lasers not provided for in groups , e.g. tandem arrangement of separate active media
8.
ACTIVELY COOLED END-PUMPED SOLID-STATE LASER GAIN MEDIUM
An actively cooled end-pumped solid-state laser gain device includes a bulk solid-state gain medium. An input-end of the gain medium receives a pump laser beam incident thereon and propagating in the direction toward an opposite output-end. The metal foil is disposed over a face of the gain medium extending between the input- and output-ends. A housing cooperates with the metal foil to form a coolant channel on the face the gain medium. The coolant channel has an inlet and an outlet configured to conduct a flow of coolant along the metal foil from the input-end towards the output-end. The metal foil is secured between the gain medium and portions of the housing running adjacent to the coolant channel. The metal foil provides a reliable thermal contact and imparts little or no stress on the bulk gain medium.
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
A thermally actuated adaptive optic includes a base, a reflector, and a plurality of actuators coupled therebetween. The reflector has a light-receiving front surface, and a back surface facing the base. Each actuator includes a bracket rigidly bonded to the reflector at a perimeter of the reflector, and an inner rod and. an outer rod. Each rod is rigidly connected between the bracket and the base, with the inner rod being closer to a center of the reflector. The length of each rod is temperature dependent. In another adaptive optic, the rods are instead bonded directly to the reflector. This adaptive optic may be modified to implement an integrally formed, thermally actuated support. The disclosed adaptive optics are suitable for use in laser systems, allow for significant cost savings over piezoelectric devices, provide a reflective area free of surface-figure perturbations caused by the actuator- interfaces, and are relatively simple to manufacture.
G02B 26/08 - Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
10.
OPTOMECHANICAL ASSEMBLIES FOR TEMPERATURE-ROBUST LASER BEAM COMBINATION AND DELIVERY
An optomechanical assembly (100) for temperature-robust laser beam processing includes a baseplate (110) and an optics plate (130). The baseplate includes a source area (112) for accommodating a source (160) of the laser beam, and a light-processing area (114) located away from the source area and including first (116) and second anchor points (118). The optics plate is disposed in the light¬ processing area and includes first (132) and second portions (134) and a flexible coupling (136) interconnecting the first and second portions. The first and second portions are fixed to the baseplate at the first and second anchor points, respectively. The flexible coupling allows for a thermally-induced change in distance between the first and second anchor points in the presence of dissimilar thermal expansion of the optics plate and the baseplate. The assembly further includes a linearly arranged series of optical elements (142) for manipulating a laser beam from the laser source. Each of the optical elements is rigidly bonded to the first portion (132). The coefficient of thermal expansion (CTE) of the optics plate (130) is matched to the CTEs of the optical elements (142).
An ultrashort-pulse compressor includes (a) one or more bulk-optics intersecting a propagation path of an ultrashort-pulsed laser beam multiple times to spectrally broaden a pulse of the laser beam during each of multiple passes through the bulk-optic(s), (b) one or more dispersive optics for compressing a duration of the pulse after each of the multiple passes, and (c) a plurality of focusing elements for focusing the laser beam between the multiple passes. Propagation distances between the bulk-optic(s) and the focusing elements are detuned from imaging such that a spot size of the laser beam, at the bulk-optic(s), is greater at each successive one of the multiple passes. As the laser beam propagates through this compressor, each laser pulse is alternatingly spectral broadened and temporally compressed. The increasing spot size of the laser, for each pass, helps prevent optical damage, run- away self-focusing, and other undesirable outcomes.
A pulsed third-harmonic laser system includes a pulsed laser, an extra-cavity nonlinear crystal, and an intracavity nonlinear crystal. The pulsed laser generates fundamental laser pulses and couples out a portion of each fundamental laser pulse out of the laser resonator to undergo second-harmonic-generation in the extra-cavity nonlinear crystal. Resulting second-harmonic laser pulses are directed back into the laser resonator and mixes with the fundamental laser pulses in the intracavity nonlinear crystal to generate third-harmonic laser pulses. The pulsed third-harmonic laser system thus maintains a non-zero output coupling efficiency regardless of the efficiency of the second-harmonic-generation stage, while the third-harmonic-generation stage benefits from the intracavity power of the fundamental laser pulses.
H01S 3/00 - Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
H01S 3/109 - Frequency multiplication, e.g. harmonic generation
H01S 3/108 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering
H01S 3/11 - Mode lockingQ-switchingOther giant-pulse techniques, e.g. cavity dumping
H01S 3/115 - Q-switching using intracavity electro-optic devices
H01S 3/08 - Construction or shape of optical resonators or components thereof
A method for laser keyhole welding is disclosed to weld two pieces together made of a metal alloy. The method independently adjusts power in a focused center beam and power in a concentric focused annular beam. At the termination of a weld, the power of the annular beam (PA) is reduced, motion of the focused beams is stopped, the power of the center beam (Pc) is increased, and the power of both beams is initially ramped down rapidly and then ramped down slowly. Increasing the power of the center beam equalizes the temperature of both pieces prior to solidification and cooling at the termination of the weld. An additional pulse of power may be applied to prevent the formation of defects or to erase any defects.
22) or carbon monoxide (CO) gas laser includes two electrodes, which have passivated surfaces, within a sealed housing. Features in a ceramic slab or a ceramic cylinder located between the electrodes define a gain volume. Surfaces of the ceramic slab or the ceramic cylinder are separated from the passivated surfaces of the electrodes by small gaps to prevent abrasion thereof. Reducing compressive forces that secure these components within the housing further reduces abrasion, thereby extending the operational lifetime of the gas laser.
H01S 3/032 - Constructional details of gas laser discharge tubes for confinement of the discharge, e.g. by special features of the discharge constricting tube
H01S 3/038 - Electrodes, e.g. special shape, configuration or composition
H01S 3/0971 - Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser transversely excited
H01S 3/07 - Construction or shape of active medium consisting of a plurality of parts, e.g. segments
H01S 3/081 - Construction or shape of optical resonators or components thereof comprising three or more reflectors
H01S 3/223 - Gases the active gas being polyatomic, i.e. containing two or more atoms
H01S 3/03 - Constructional details of gas laser discharge tubes
An optical parametric chirped-pulse amplifier includes first and second optical parametric amplifier stages that successively amplify a stretched signal beam. A pulsed laser provides a fundamental beam. The second amplifier stage is pumped by the full power of a second-harmonic beam that is generated from the fundamental beam. A residual fundamental beam is used to generate another second-harmonic beam that pumps the first amplifier stage.
A wavelength sensor for wavelength stabilization of a laser beam includes an etalon placed in the laser beam and tilted with respect to the laser beam. Reflected beams from the etalon form an interference pattern on a segmented photodetector having two detector segments. Output signals from the two detector segments are used to derive an error signal for a closed control loop to effect the wavelength stabilization.
H01S 5/0687 - Stabilising the frequency of the laser
H01S 3/137 - Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling devices placed within the cavity for stabilising of frequency
H01S 3/139 - Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the mutual position or the reflecting properties of the reflectors of the cavity
H01S 3/08 - Construction or shape of optical resonators or components thereof
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.
An apparatus includes a beam source, beam forming optics, a first focusing lens having a focal length, a second focusing lens having a focal length similar to the focal length of the first lens, and a lens translator configured to move the second lens transversely relative to the beam forming optics and to the first lens, and thereby move the elongated focus transversely. In some embodiments, the beam forming optics are positioned between the beam source and the first focusing lens, the first focusing lens is positioned between the beam forming optics and the second focusing lens, and the beam forming optics, the first focusing lens, and the second focusing lens are arranged to receive a beam of laser radiation from the beam source and to form the beam into an elongated focus.
G02B 26/08 - Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
G02B 27/09 - Beam shaping, e.g. changing the cross-sectioned area, not otherwise provided for
B23K 26/06 - Shaping the laser beam, e.g. by masks or multi-focusing
A method for laser keyhole welding of metal alloys is disclosed. The method independently adjusts power in a focused center beam and power in a concentric focused annular beam. At the termination of a weld, the power in the center beam is initially ramped up and then ramped down, while the power in the annular beam is ramped down. Increasing the power in the center beam enables a controlled and prolonged contraction of the keyhole and melt pool, thereby preventing undesirable cracking.
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.
A source of high-radiance broad-band incoherent light includes an optical waveguide, having a core made of phosphor granules embedded in a matrix of glass and a cladding. The core having a relatively high refractive index and the cladding having a relatively low refractive index. The phosphor granules and the glass matrix having about the same refractive index. Radiation from one or more diode-lasers is injected into one end of the waveguide to energize the phosphor granules, producing broad-band incoherent light, which is confined and guided to an opposite end of the waveguide as output light.
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.
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.
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/00 - Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
H01S 5/062 - Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
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.
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.
G02B 9/16 - Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or – having three components only arranged + – + all the components being simple
G02B 13/00 - Optical objectives specially designed for the purposes specified below
Apparatus for distance gauging in laser material processing includes a source of laser-radiation, an electrically-conductive focusing assembly, a constant-current source, and a voltmeter. The focusing assembly focuses laser-radiation towards an electrically conductive workpiece being processed. The focusing assembly and the workpiece form a capacitive sensor. The constant current source provides a constant electrical current to the focusing assembly for a constant time. The focusing assembly and the workpiece are separated by a distance that is proportional to a change in voltage measured on the focusing assembly during the constant time.
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.
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
A fiber-laser includes a gain-fiber in a laser-resonator. A polarizer is located in the laser-resonator at an end thereof, causing the output of the fiber-laser to be linearly polarized. A wavelength-selective element is also included in the laser-resonator for selecting an output wavelength of the fiber-laser from within a gain-bandwidth of the gain-fiber.
An apparatus for cutting brittle material comprises beam expander (18) in combination with an aspheric focusing lens (22), an aperture (CA), and a laser-source (12) generating a beam (14) of pulsed laser-radiation. The aspheric lens (22) and the aperture (CA) form the beam (24) of pulsed laser-radiation into an elongated focus having a uniform intensity distribution along the optical axis of the aspheric focusing lens (22). The elongated focus extends through the full thickness of a workpiece (38) made of a brittle material. The workpiece (38) 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 (38).
B23K 26/08 - Devices involving relative movement between laser beam and workpiece
C03B 33/09 - Severing cooled glass by thermal shock
B23K 26/53 - Working by transmitting the laser beam through or within the workpiece for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
B23K 26/0622 - Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
B23K 26/066 - Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms by using masks
B23K 103/00 - Materials to be soldered, welded or cut
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.
A laser-radiation detector is formed from a plurality of layers supported on a substrate. The plurality of layers includes a reflective metal layer and an oriented polycrystalline sensor-layer positioned between the metal layer and the substrate.
G01J 5/06 - Arrangements for eliminating effects of disturbing radiationArrangements for compensating changes in sensitivity
G01J 5/12 - Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using thermoelectric elements, e.g. thermocouples
A method of delivering a beam of laser-radiation to a workpiece for processing the workpiece comprises transmitting the beam twice through an 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.
B23K 26/02 - Positioning or observing the workpiece, e.g. with respect to the point of impactAligning, aiming or focusing the laser beam
G02F 1/11 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
33.
APPARATUS FOR GENERATING A LINE-BEAM FROM A DIODE-LASER ARRAY
An apparatus for generating a line beam (26) includes a diode laser bar (20), a linear microlens array (34) and a plurality of lenses (30, 32, 36, 38) spaced apart and arranged along an optical axis. The linear microlens array (34) and the lenses (30, 32, 36, 38) shape laser radiation emitted by the diode laser bar (20) to form a uniform line beam (26) in an illumination plane (28). The lenses (30, 32, 36, 38) project a far-field image of the diode laser bar (20) onto an image plane (62) proximate to the illumination plane (28). The diode laser bar (20) is rotated from parallel alignment with the linear microlens array (34) for providing uniform line beam illumination over a range of locations along the optical axis.
In a flow cytometer, an objective lens (20) focuses in a common plane (P) an input laser-beam having four different wavelengths. The objective (20) consists of three single-lenses (CL1, CL2, FFL), the two first ones (CL1, CL2) being cylindrical for shaping and reducing the size of the input laser-beam, the third one (FFL) being spherical to focus the reduced-size laser-beam in the common plane (P).
G02B 9/16 - Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or – having three components only arranged + – + all the components being simple
G02B 13/00 - Optical objectives specially designed for the purposes specified below
G02B 27/09 - Beam shaping, e.g. changing the cross-sectioned area, not otherwise provided for
G01N 15/14 - Optical investigation techniques, e.g. flow cytometry
A61B 18/20 - Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
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.
A modular solid-state laser (10) comprises a fiber coupled diode-laser pump module (20) and a laser-enclosure (50). The diode-laser pump module comprises a connector assembly 26 including a collimating lens (32) and produces a collimated beam (28B) of laser-radiation for pumping a gain-element (56) within the laser-enclosure. The beam of pump laser-radiation is focused into the gain-element by optics (54) located within the laser-enclosure. The diode-laser pump module can be replaced or exchanged without realigning optics located within the laser-enclosure by detaching and replacing the connector assembly from the laser enclosure.
H01S 3/094 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
H01S 3/06 - Construction or shape of active medium
G02B 6/38 - Mechanical coupling means having fibre to fibre mating means
37.
STACKABLE ELECTRICALLY-ISOLATED DIODE-LASER BAR ASSEMBLY
A diode-laser bar assembly comprises a diode-laser bar mounted onto a cooler by way of an electrically-insulating submount. A laminated connector is provided that includes two electrically-conducting sheets bonded to opposite sides on an electrically- insulating sheet. An electrical insulator is located between the laminated connector and the cooler. One electrically-conducting sheet is connected to n-side of the diode-laser bar and the other electrically-conducting sheet is connected to p-side of the diode-laser bar.
A method for cutting a transparent brittle material using pulsed laser-radiation is disclosed. A beam of pulsed laser-radiation having an optical-axis is focused in the material by a variable-focus lens or mirror. The focus is translated along the optical-axis while the material is moved with respect to the beam to create an array of defects along a cutting path.
C03B 33/02 - Cutting or splitting sheet glassApparatus or machines therefor
B23K 26/53 - Working by transmitting the laser beam through or within the workpiece for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
B23K 26/0622 - Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
B23K 103/00 - Materials to be soldered, welded or cut
A cooler for diode-laser bars comprises a machined base including a water- input plenum and a water-output plenum, and a top plate on which the diode-laser bars can be mounted. A stack of three etched plates is provided between the base and first plate. The stack of etched plates is configured to provide a five longitudinally spaced- apart rows of eight laterally spaced-apart cooling-channels connected to the water-input and water-output plenums. Water flows in the cooling-channels and in thermal contact with the first plate.
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.
A mode- stripper for an optical fiber includes a water-cooled enclosure. A portion of an optical fiber to be mode-stripped is modified in a way which allows radiation to leak from cladding of the fiber. The optical fiber extends through the enclosure from a proximal end thereof to a distal end thereof, with the modified portion of the fiber within the enclosure. The fiber is fixedly held in the enclosure at the proximal end thereof and held at the distal end of the enclosure by an elastomeric diaphragm.
A diode-laser assembly having an electrically isolated diode-laser bar (20) on a cooled base-element (80) 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.The laser diode bar (20) may be attached to an insulating submount (70) by a hard solder (110). The submount (70) may be attached to a base (80) by a soft solder (120). The upper surface of the submount (70) may be plated with copper (90) to allow wire bonding (150) of the p-side (40) of the laser diode bar to an electrical p-contact (130).. The n-side (30) of the laser diode bar is wire bonded (190A,190B) to electrical n-contacts (170A,170B).
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.
B23K 26/0622 - Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
B23K 26/064 - Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
B23K 26/067 - Dividing the beam into multiple beams, e.g. multi-focusing
G02F 1/11 - Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulatingNon-linear optics for the control of the intensity, phase, polarisation or colour based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
An apparatus for generating and amplifying laser beams at approximately 1 micrometer wavelength is disclosed. The apparatus includes an ytterbium-doped gain-crystal pumped by an ytterbium fiber-laser. The fiber-laser enables a pump wavelength to be selected that minimizes heating of the gain-crystal. The apparatus can be configured for generating and amplifying ultra- fast pulses, utilizing the gain-bandwidth of ytterbium-doped gain-crystals.
Laser-machining apparatus includes a carbon monoxide (CO) laser emitting a beam of laser-radiation having forty-four different wavelength components and optical elements for delivering the radiation to workpiece. An acousto-optic modulator is provided for modulating the beam on the workpiece. A birefringent plate is provided in the beam transported to the workpiece for randomly polarizing radiation incident on the workpiece. A minimum distance of the workpiece from the laser, and the number of different-wavelength components in the laser beam provides that no optical isolator is required for preventing feedback of radiation into the laser.
Plane-polarized laser-radiation from a laser-source is converted to circularly polarized radiation by a quarter-wave plate (12). The circularly polarized radiation is input into a hollow-core fiber for transport to a point of use (20). The transported radiation is converted back to plane-polarized radiation by another quarter-wave (22) plate between the fiber and the point of use.
A carbon dioxide waveguide-laser includes an elongated resonator compartment and an elongated RF power supply compartment. The resonator and RF power-supply compartments are separated by a water-cooled heat sink.
Diverging beams (13, 15, 17) from three fiber-lasers (12, 14, 16) are collimated by a three-segment composite lens (20). The collimated beams propagate parallel to each other to a single focusing lens (32) that focuses the collimated beams into a transport fiber (18).
A carbon dioxide waveguide-laser includes an elongated resonator unit and an elongated RF power-supply unit. The resonator and RF power-supply units are spaced by a air cooling unit including a plurality of longitudinally extending, spaced-apart fins, with fans arranged to drive air through the spaces between the fins.
The present disclosure is directed to simultaneously controlling peak pulse power and pulse energy in gas-discharge lasers. In an aspect, a radio-frequency power supply (104) that is coupled to a gas-discharge laser (102) is turned ON to initiate delivery of a laser pulse. The radio-frequency power supply is modulated ON/OFF to maintain the amplitude of the laser pulse at about a desired or prescribed value. Further, the radio-frequency power supply is turned OFF to terminate delivery of the laser pulse when the accumulated energy reaches reached a predefined energy threshold value.
H01S 3/03 - Constructional details of gas laser discharge tubes
H01S 1/06 - Masers, i.e. devices using stimulated emission of electromagnetic radiation in the microwave range gaseous
H01S 3/091 - Processes or apparatus for excitation, e.g. pumping using optical pumping
H01S 3/134 - Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the active medium, e.g. by controlling the processes or apparatus for excitation in gas lasers
An architecture for current driver circuitry for diode laser systems is contemplated whereby the circuitry is both modular and minimally complex with respect to the number of components and connections.
H02M 3/158 - Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
H03K 17/785 - Electronic switching or gating, i.e. not by contact-making and -breaking characterised by the use of specified components by the use, as active elements, of opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling field-effect transistor switches
A light-source includes a planar array of diode-laser bars and a plurality of turning- mirrors arranged to stack beams from the diode-laser bars in the fast-axis direction to provide a first combined beam. Six plane mirrors are arranged to divide the combined beam into three beam-slices, each having one-third the slow-axis width of the first combined beam, and add the beam-slices in the fast-axis direction to provide a second combined beam having about one-third the slow-axis width and three-times the fast-axis length of those of the first combined beam. A spherical mirror and a cylindrical mirror focus the second combined beam into an optical fiber.
A source of femtosecond laser pulses at center wavelengths of about 940 nm and about 1140 nanometers (nm) includes a mode-locked fiber MOPA delivering pulses having a center wavelength of about 1040 nm. The 1040-nanometer pulses are spectrally spread into a continuum spectrum extending in range between about 900 nm and about 1200 nm and having well defined side-lobes around the 940- nm and 1140- wavelengths. Radiation is spatially selected from these side-lobes and delivered as the 940-nm, 1040 nm, and 1140-nm pulses.
Optical apparatus (40) includes a diode-laser bar stack (42) having N fast-axis stacked diode-laser bars (17) cooperative with a parallel sided transparent stacking plate (50). The stacking plate receives N original beams (44) from the N diode-laser bars and converts the N beams to 2N fast-axis stacked beams (44A, 44B) having one-half of a width the original beams and one-half of a fast-axis spacing between the original beams. The transparent plate has parallel surfaces (50A,50B) with the surfaces being tilted in both perpendicular directions versus the incoming laser beams (44). The second surface (50B) is coated with a reflective coating (66) that reflects half of the width of the incoming beams towards reflective coating stripes (60) on the first surface (50A) thereby interleaving the reflected beams (44B) between the remainder of the incoming beams (44A) in order to increase the filling factor of the overall laser beam.
An optical apparatus for delivering to a flow-cell of a flow-cytometer a plurality of beams of laser radiation each thereof having a different wavelength. The apparatus includes a dispersion compensation-prism and a plurality of directing-prisms equal in number to the number of laser-beam. The directing-prisms are arranged to direct the laser radiation beams directly therethrough into the dispersion compensation-prism as converging fan of beams in a first plane. The beams are transmitted by the compensation-prism as a converging fan of beams intersecting then proceeding as a diverging fan of beams in the first plane. A spherical focusing lens is arranged cooperative with a cylindrical lens for focusing the plurality of laser-beams as a plurality of spaced apart elongated focal spots in a plane in which the cytometer flow-cell is located.
G02B 27/09 - Beam shaping, e.g. changing the cross-sectioned area, not otherwise provided for
G02B 26/00 - Optical devices or arrangements for the control of light using movable or deformable optical elements
G02B 6/28 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
Apparatus (10) for drilling a via-hole in a printed circuit board (PCB) (74) includes a carbon monoxide laser (12) deliver laser radiation pulses. The pulses have a relatively broad wavelength-range, and slow rising and falling edges. The rising and falling edges of the pulses are clipped using and acousto-optic modulator (52). A dispersion- compensator (64) compensates for dispersion in the clipped pulses introduced by the AOM (52). Achromatic focusing optics (70) focus the dispersion-compensated, clipped pulses on the PCB (74) for the via- hole drilling.
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. At least two protection layers are positioned between the sensor layer and the absorber layer.
G01J 5/12 - Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using thermoelectric elements, e.g. thermocouples
A radio-frequency (RF) planar transformer includes three spaced-apart, single-turn primary strip-windings connected electrically in parallel with each other. A one-turn secondary strip-winding is located between each adjacent pair of primary strip-windings. The secondary strip-windings are connected in electrical series with each other. The transformer functions as a transformer having a one-turn primary winding and a two-turn secondary winding.
A laser label printer for use with a laser markable medium includes a laser-diode fiber-coupled to an optical train, which includes a focusing lens for focusing the radiation on the medium. The focusing lens is traversed across the medium, with incremental motion of the medium between traverses, for line by line printing of the label. The printer includes a feature for protecting the focusing lens from contamination, and self-diagnostic and adjustment features.
B41J 2/47 - Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using the combination of scanning and modulation of light
B41J 3/407 - Typewriters or selective printing or marking mechanisms characterised by the purpose for which they are constructed for marking on special material
A chirped pulse amplifier having a solid-state laser amplifier (12) for use as a final amplification stage for a fibre-MOPA, the system comprising fibre pre-amplifier (64,70,74,75), a grating stretcher (66) and a pulse picker (72) for reduction of the pulse repetition rate. The final solid-state high-power amplifier has a gain-element including a thin wafer or chip of ytterbium-doped YAG (14). An elongated gain- region (26) is formed in gain-element by multiple incidences of radiation from a diode-laser bar (20).
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
H01S 3/23 - Arrangement of two or more lasers not provided for in groups , e.g. tandem arrangement of separate active media
H01S 3/06 - Construction or shape of active medium
A diode-laser bar (60) is mounted on water-cooled heat-sink (20) between two ceramic sub-mounts (62A,62B) for electrically isolating cooling-water in the heat-sink from the diode-laser bar. Mounting between the two ceramic sub-mounts also provides for balancing stresses due to differences in coefficient of thermal expansion (CTE) between the sub-mounts and the diode-laser bar. Both sub-mounts are in thermal communication with the heat-sink for providing two- sided cooling of the diode-laser bar. The assembly of the LD bar (60) hard soldered to the BeO or AIN ceramic sub-mounts (62A,62B) may be inserted into the open space (25) between integral fingers (24) of the heat sink, each finger (24) having a macro-channel (50) for water cooling.
A water-cooled heat-sink (20) for a diode-laser bar includes a copper- cooling-unit (22) having an integral mount (24) thereon for the diode- laser bar (). The copper-cooling-unit is attached to a steel base-unit (28). The base-unit and the cooling-unit are cooperatively configured such that at least one cooling-channel is formed in the cooling-unit by the attachment of the base-unit to the cooling-unit. The cooling- channel is positioned to cool the mount (24) when cooling-water flows through the cooling-channel. Fins (34) are provided to guide the cooling water in the slots (42).
A laser-radiation sensor (30) includes a copper substrate (32) on which is grown an oriented polycrystalline buffer layer (34) surmounted by an oriented polycrystalline sensor-element of an anisotropic transverse thermoelectric material (36). An absorber layer (42), 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 (38, 40) in electrical contact with the sensor-element sense a voltage corresponding to the thermal gradient as a measure of the incident laser-radiation power.
G01J 5/12 - Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using thermoelectric elements, e.g. thermocouples
In a line projector a diode-laser (22) beam having an elliptical cross-section is projected onto a Powell lens (40) which spreads the beam to form a line of light. Distribution of power along the line of light is adjusted by rotating the diode-laser (22) beam with respect to the Powell lens (40).
In order to maintain a constant laser output pulse power in a RF-energized, sealed-off, diffusion cooled, pulsed, CO2 gas-discharge laser (160), each laser output pulse is generated by train or burst of shorter RF pulses. When the time between laser output pulses (176) becomes short enough that the power in one pulse would be reduced by gas-discharge heating effects of a previous pulse, power in the RF pulse trains (164) is varied by varying the duration or duty cycle of pulses in the bursts, thereby keeping output-pulse power in the laser output pulses constant. RF pulses in any burst can have a different duration for tailoring the temporal shape of a corresponding laser-output pulse.
H01S 3/104 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the active medium, e.g. by controlling the processes or apparatus for excitation in gas lasers
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/097 - Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
H01S 3/223 - Gases the active gas being polyatomic, i.e. containing two or more atoms
A compact C02 slab-laser is contained in a fluid cooled housing (40) having three compartments (46, 48, 50). One compartment (48) houses discharge electrodes (70, 71) and a laser resonator. Another compartment (48) houses a radio-frequency power supply (RFPS) assembled on a fluid-cooled chill plate (82) and an impedance- matching network. The remaining compartment (50) houses beam- conditioning optics including a spatial filter (290, 340). The housing (40) and RFPS chill-plate (82) are on a common coolant-fluid circuit having a single input (214, 259) and a single output (216, 272). The spatial filter (290, 340) is optionally fluid-coolable on the common coolant fluid circuit.
In a frequency-tripled fiber-MOPA, a plane-polarized seed-pulse having a fundamental frequency is pre-amplified (16). Subsequently, the polarisation is rotated by 45° with half-wave plate (20), creating two orthogonally polarised pulses (PF1,PF2), which may be delayed (42) in time. The fundamental-wavelength pulse- components are amplified in a common amplifier-fiber (22)utilizing a polarisation maintaining fibre (22A). The amplified components are separately propagated on different optical paths. One of the amplified components is frequency-doubled (26). The frequency- doubled component (P2H) on one path and fundamental-frequency component (PF2) on the other path are then combined on a common- path and sum-frequency mixed (36) to provide a frequency-tripled pulse.
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
68.
ATHERMALIZED PERMANENT-ALIGNMENT OPTICAL-ELEMENT MOUNT
A mounting fixture for mounting an optical element on a base-plate has spaced-apart parallel legs attachable by brackets to the base-plate and a mounting platform attached to the legs. The platform can be heated by a removable heater. The optical element is held in a mounting tab attached to the platform by a solder-pad. Heating the platform softens the solder- pad allowing the tab and the element to be aligned. Removing the heat allows the pad to harden to complete the attachment and retain the alignment of the element on the mount.
G02B 7/00 - Mountings, adjusting means, or light-tight connections, for optical elements
G02B 7/02 - Mountings, adjusting means, or light-tight connections, for optical elements for lenses
G02B 7/18 - Mountings, adjusting means, or light-tight connections, for optical elements for prismsMountings, adjusting means, or light-tight connections, for optical elements for mirrors
69.
OUTPUT-POWER CONTROL APPARATUS FOR A CO2 GAS-DISCHARGE LASER
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.
H01S 3/097 - Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
H01S 3/13 - Stabilisation of laser output parameters, e.g. frequency or amplitude
H01S 3/134 - Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling the active medium, e.g. by controlling the processes or apparatus for excitation in gas lasers
70.
MULTIPLE PHASE-LOCKED LOOPS FOR HIGH-POWER RF-POWER COMBINERS
An RF power-supply (30) for driving a carbon dioxide CO2 gas- discharge laser (28) includes a plurality of power-oscillators (32) phase-locked to a common reference oscillator (11). Outputs of the phase-locked power-oscillators (32) are combined by a power combiner (18) for delivery, via an impedance matching network (22), to discharge-electrodes (24, 26) of the laser (28). In one example the power-oscillators are analog power-oscillators. In another example, the power-oscillators are digital power-oscillators.
H03L 7/22 - Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop using more than one loop
H03L 7/23 - Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop using more than one loop with pulse counters or frequency dividers
71.
BEAM-COMBINER FOR FIBER-DELIVERED LASER-BEAMS OF DIFFERENT WAVELENGTHS
A beam combiner for combining laser-beams of different colors along a common path includes a directing-prism (P1, P2, P3, P4, P5) for each of the laser-beams and one combining-prism (Pw). The direct- ing-prisms are arranged to transmit the laser-beams to the combining-prism. The directing-prisms and the combining-prism are configured and arranged with respect to each other such that the directing-prism transmits the beams along the common path. In another embodiment the laser-beams are focussed by a lens on a combining prism.
G02B 6/293 - Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
72.
APPARATUS AND METHOD FOR BALANCING COMBINED RF POWER-SUPPLIES FOR DRIVING A CO2 GAS-DISCHARGE LASER
Radio-frequency (RF) power supply apparatus (40) for supplying RF power to discharge electrodes (22, 24, 26) of a gas-discharge laser includes a plurality of amplifier modules (Al - A6) each having an RF output. A power combining arrangement (20) is provided for combin- ing the amplifier module RF- outputs into a single combined RF-output connected to the discharge electrodes (24, 26). A DC power supply (30) is connectable to or disconnectable from each of the transistor amplifier modules (Al - A6), separately, to allow current drawn by any of the amplifier modules (Al - A6) to be monitored by a single current sensor (CS1 -CS6).
A laser (12) and amplifier (42) combination delivers a sequence of optical pulses at a predetermined pulse-repetition frequency PRF. An interferometer (54) generates a signal representative of the carrier-envelope phase (CEP) of the pulses at intervals corresponding to the PRF. The signal (56) includes frequency components from DC to the PRF. The signal (56) is divided into high (64) and low frequency (65) ranges. The high and low frequency ranges (64, 65) are sent to independent high frequency (64) and low frequency (60) control electronics, which drive respectively a high-frequency CEP controller (36) and a low frequency controller (40) for stabilizing the CEP of pulses in the sequence.
A laser (10) includes an optically pumped semiconductor OPS gain- structure (16). The apparatus has a laser-resonator (11) which includes a mode-locking device for causing the laser to deliver modelocked pulses. The resonator has a total length selected such that the mode-locked pulses are delivered at a pulse repetition frequency of about 100 MHz. An optical arrangement within the resonator provides that radiation circulating in the resonator makes a plurality of incidences on the OPS gain-structure with a time less than the excited-state lifetime of the gain-structure between successive incidences.
H01S 5/183 - Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
H01S 5/34 - Structure or shape of the active regionMaterials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
H01S 3/11 - Mode lockingQ-switchingOther giant-pulse techniques, e.g. cavity dumping
75.
FIBER-MOPA APPARATUS FOR DELIVERING PULSES ON DEMAND
A fiber-MOPA includes a seed-pulse source followed by fiber amplifier stages. The seed pulse source delivers signal pulses for performing a laser operation and delivers radiation between the seed pulses to maintain the collective average of the seed pulse power and intermediate radiation power constant. Keeping this average power constant keeps the instantaneous available gain of the fiber amplifier stages constant. This provides that the seed pulse delivery can be changed from one regime to a next without a period of instability between the regimes.
H01S 3/13 - Stabilisation of laser output parameters, e.g. frequency or amplitude
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/00 - Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
76.
WAVEGUIDE CO2 LASER WITH MULTIPLY FOLDED RESONATOR
A gas-discharge waveguide C02 laser has a Z-shaped folded waveguide formed by three ceramic tubes. Ends of the adjacent tubes are shaped and fitted together to form a common aperture. The tubes are held fitted together by spaced-apart parallel discharge electrodes. Four mirrors are arranged to form a laser-resonator having a longitudinal axis extending through the tubes.
H01S 3/03 - Constructional details of gas laser discharge tubes
H01S 3/223 - Gases the active gas being polyatomic, i.e. containing two or more atoms
H01S 3/038 - Electrodes, e.g. special shape, configuration or composition
H01S 3/081 - Construction or shape of optical resonators or components thereof comprising three or more reflectors
H01S 3/0975 - Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser using inductive or capacitive excitation
H01S 3/032 - Constructional details of gas laser discharge tubes for confinement of the discharge, e.g. by special features of the discharge constricting tube
H01S 3/036 - Means for obtaining or maintaining the desired gas pressure within the tube, e.g. by gettering or replenishingMeans for circulating the gas, e.g. for equalising the pressure within the tube
77.
OPTICALLY-PUMPED SURFACE-EMITTING SEMICONDUCTOR LASER WITH HEAT-SPREADING COMPOUND MIRROR-STRUCTURE
A gain-module (12) for use in an OPS -laser includes a multilayer semiconductor gain - structure (14) surmounting a multilayer compound mirror- structure (16). Within the multilayer compound mirror- structure is a relatively thick layer of diamond (20) which serves as a heat - spreader. The compound mirror- structure (16) comprises a partially reflecting DBR (18) and a high reflective DBR (22). The resonator may comprise a nonlinear crystal (32) for SHG. The thickness of the diamond (20) is about 1 mm.
H01S 5/183 - Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
Ring-field, catoptric and catadioptric, unit-magnification, projection optical systems having non-concentric optical surfaces are disclosed. Each system has a system axis with object and image planes on opposite sides of the system axis. The non-concentric surfaces allow for working distances of the object and image planes in excess of 100 millimeters to be achieved, with a ring-field width sufficient to allow a rectangular object- field having a long dimension in excess of 100 mm to be projected.
An OPS-chip is soldered mirror- structure- side down on an upper surface of diamond-heat spreader. A metal frame is also soldered to the upper surface of the heat- spreader. The lower surface of the diamond heat-spreader is either soldered to, or clamped against, a surface of a heat-sink. The dimensions of the frame and the heat spreader are selected such that at a solidification temperature of the solder at the center of the upper surface of the heat-spreader has an effective CTE comparable with that of the OPS-chip. The lower surface of the heat-spreader can be soldered to the heat sink surface or clamped against the heat-sink surface by the frame.
H01S 5/183 - Surface-emitting [SE] lasers, e.g. having both horizontal and vertical cavities having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
A laser includes a Ti : sapphire gain-medium (18) in the form of a thin-disk. The thin-disk gain-medium is optically pumped by pump - radiation pulses (12) having a wavelength in the green region of the electromagnetic spectrum. The pump - radiation pulses have a duration less than twice the excited- state lifetime of the gain-medium. Multipass pumping is realized with pump mirrors (40, 42) and the thin-disk (18) is mounted via a diamond heat spreader (28) on a water cooled copper heat sink (22,24). For thermal management, low doping and large pump spots are used.
Projection apparatus for projecting a radiation spot on a working plane includes a plurality of stacks of diode-laser bars. Each stack provides a beam of laser radiation. The diode-laser bars in each stack are arranged one above another in the fast-axis direction of the diode-laser bars. A corresponding plurality of beam-expanders expands the beam from the corresponding diode-laser bar stack in the slow-axis direction of the diode laser bars only. A focusing lens collects the slow-axis expanded beams and projects the slow-axis expanded beams into the working plane to form the radiation spot.
A CW fiber- laser includes a gain fiber (42) having a reflector (44) proximity-coupled to one end (42A), with the other end left (42B) uncoated. A laser resonator is defined by the reflector (44) and the uncoated end (42B) of the gain-fiber. Pump - radiation from two fast-axis diode-laser bar stacks (46) is combined and focused into the uncoated end (42B) of the gain - fiber for energizing the fiber. Laser radiation (37) resulting from the energizing is delivered from the uncoated end of the gain -fiber and separated from the pump - radiation by a dichroic mirror (31). A coupler (60) is provided at the uncoated end (42B) of the fiber to absorb pump light not guided in the cladding of the fibre (42).
H01S 3/08 - Construction or shape of optical resonators or components thereof
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
H01S 3/094 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
H01S 3/105 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the mutual position or the reflecting properties of the reflectors of the cavity
H01S 5/40 - Arrangement of two or more semiconductor lasers, not provided for in groups
83.
DELIVERY FIBER FOR SURGICAL LASER TREATMENT AND METHOD FOR MAKING SAME
An optical surgical fiber assembly for delivering laser radiation from a laser radiation source to a treatment site has a sealed off capillary enclosing a delivery end of the fiber. The capillary is formed from an outermost layer of fused silica and an adjacent layer of boron-doped fused silica having a higher CTE than that of the fused silica. The capillary is shrink-fitted onto the delivery end of the fiber. A compressive stress is imparted to the outermost layer of the capillary as a result of the shrink-fitting process and the CTE difference between the layers. This provides mechanical hardening of the surface of the outermost layer.
C03B 37/016 - Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means by a liquid phase reaction process, e.g. through a gel phase
A61B 18/22 - Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibreHand-pieces therefor
84.
OPTICAL PARAMETRIC OSCILLATOR PUMPED BY FEMTOSECOND THIN-DISK LASER
Pulses from a mode-locked Yb-doped laser (12) are spectrally broadened in an optical fiber (28), and temporally compressed in a grating compressor (32), then frequency-doubled (34) and used to pump an optical parametric oscillator (OPO) (40). The OPO output is tunable over a wavelength range from about 600 nm to about 1100 nm. Mode - locking in the Yb-doped laser (12) is accomplished with a SESAM (14) or by Kerr-lens mode-locking with a Kerr medium (82) and a hard aperture (84).
G02F 1/39 - Non-linear optics for parametric generation or amplification of light, infrared, or ultraviolet waves
H01S 3/11 - Mode lockingQ-switchingOther giant-pulse techniques, e.g. cavity dumping
85.
POWDER - DELIVERY APPARATUS FOR LASER - CLADDING BEING ADJUSTABLE IN X, Y AND Z CARTESIAN AXES AND COMPRISING ALSO AN ARRANGEMENT FOR BLOCKING SELECTED NOZZLE (S)
A powder-delivery apparatus for delivering powdered cladding -material into the vicinity of a laser-beam spot includes a plurality of powder-delivery modules (80 a-c). Each of the modules is arranged to receive the cladding-material and deliver the cladding-material through a plurality of nozzles. The position of the nozzles in the modules (80 a-c) with respect to the laser-beam spot is adjustable in three Cartesian axes. The modules (80 a-c) are selectively removable from, and attachable to the apparatus. Nozzles in any one of the modules (80 a-c) can be selectively prevented from delivering cladding -material.
B23K 26/14 - Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beamNozzles therefor
B23K 26/34 - Laser welding for purposes other than joining
B05B 7/14 - Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas designed for spraying particulate materials
B05B 7/22 - Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas incorporating means for heating the material to be sprayed electrically, e.g. by arc
A diode-laser is driven by a modulated voltage through a voltage - to - current converter. The modulated voltage has a fixed level determined by an applied fixed bias voltage and a variable level determined by a modulation voltage signal varying between minimum and maximum values. The fixed voltage level corresponds to a threshold level above which the diode -laser would provide laser-output. The modulation voltage signal is monitored and compared with a predetermined set value. If the monitored voltage signal falls below the set value, the modulated voltage is disconnected from the voltage - to - current converter and the output of the diode-laser falls to zero. By this, the diode- laser is prevented from outputting spontaneous emission of fluorescence.
A mode-locked fiber laser has a resonator including a gain-fiber, a mode-locking element, and a spectrally-selective dispersion compensating device. The resonator can be a standing-wave resonator or a traveling- wave resonator. The dispersion compensating device includes only one diffraction grating combined with a lens and a mirror to provide a spatial spectral spread. The numerical aperture of the gain-fiber selects which portion of the spectral spread can oscillate in the resonator.
In optical apparatus for illuminating a mask-plane with a line of light, a light source includes four fast-axis stacks of laser diode bars with fast and slow axis collimating arrangements providing four collimated beams of diode-laser light. A combination of a lens element and two diffraction gratings collects the four collimated beams and spreads the beams in the fast-axis direction such that the spread beams overlap in the mask plane to form a line of light having a length in the fast- axis-direction and a width in the slow-axis direction of the diode-laser bar stacks.
Electrical apparatus for connecting a radio frequency power- supply having two outputs (Source A- Source B) to a load includes two radio frequency transmission - lines, each one connected to a corresponding power-supply output, transformer arrangement connects the two transmission - lines to the load (34). Each transmission - line includes a series - connected pair of twelfth- wave transmission - line sections (24A, 24B, 28A, 28B). The series - connection (26A) between the twelfth wave transmission - line sections in one transmission line i connected to the series - connection (26B) between the twelfth-wave transmission - line sections in the other by a device (38) having an adjustable impedance.
A unit magnification projection optical system includes, listed in order along a system axis, a mirror, a lens group having negative power and a lens group having positive power. The optical system is a symmetric system, with an object plane on one side of the system axis and an object plane on an opposite side of the system axis. The object and image planes are spaced apart from the positive lens group by a working distance greater than 100 millimeters.
In optical apparatus for illuminating a mask-plane with a line of light, a light source includes four fast- axis stacks of laser diode bars. One optical arrangement collects light beams from all of the diode-laser bar stacks, homogenizes and expands the beams in the fast- axis direction of the diode-laser bar stacks and partially overlaps the homogenized and expanded beams in the fast-axis direction. Another optical arrangement homogenizes the sum of the partially overlapped beams and images the sum of the beams as a line of light having a length in the fast-axis-direction and a width in the slow-axis direction.
A master oscillator power-amplifier stages includes multiple stages of fiber-amplification (34, 54, 58) with a final power amplifier stage in the form of a multi-pass amplifier (64). With a thin-disk gain medium (66) in one example the thin-disk amplifier includes a common optical arrangement (74, 76, 78, 120) for providing multiple incidences of radiation to be amplified and multiple incidences of a pump - radiation beam (70) on the thin-disk gain medium (66). The use of a thin-disk power amplifier allows to avoid non-linear pulse broadening, circumvents the need for a CPA while keeping the footprint of the MOPA small.
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
In a C02 gas discharge laser energized by a radio frequency (RF) power source a transformer (20) having selectively variable output impedance is used to match output impedance of the power source to the impedance of discharge electrodes of the laser. A similar transformer (40) can be used to impose a selective variable phase -shift on the RF power from the source. The variable impedance transformer can also be used for impedance matching between amplifier stages in the power source. The transformer comprises first (28, 46) and second (32, 48) transmission - line sections connected in series between and the load. Each of the first and second transmission - line sections having an electrical length equal to or less than about one- twelfth of a wavelength at the source- frequency. A selectively variable electrical component (Cv, Lv) is connected to the node between the first and second transmission - line sections to optimize the transfer of RF- power between the source and the load.
Multi-pass optical imaging apparatus includes a concave mirror (14) in combination with two retro - reflecting mirror pairs (20,40) and at least one reflective surface (30,32). The mirror, the retro- reflecting mirror pairs and the reflecting surface are arranged such that a light -ray input into the apparatus parallel to and spaced apart from the optical axis of the concave mirror and incident on the concave mirror is caused to be incident on the thin-disk gain-medium (18) at least four times, with each of the four incidences on the gain-medium being from a different direction. If the input ray is plane -polarized, the arrangement provides that the polarization orientation of the ray on each incidence on the gain -medium is in the same orientation.
H01S 3/06 - Construction or shape of active medium
H01S 3/094 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
H01S 3/23 - Arrangement of two or more lasers not provided for in groups , e.g. tandem arrangement of separate active media
95.
RESONANT PUMPING OF THIN-DISK LASER WITH AN OPTICALLY PUMPED EXTERNAL-CAVITY SURFACE-EMITTING SEMICONDUCTOR LASER
Laser apparatus comprises a solid-state laser-resonator including a thin-disk solid-state gain-medium. The thin-disk gain medium is optically pumped using radiation circulating in an OPS-laser resonator. The solid-state laser-resonator can be a passively mode-locked or actively Q-switched laser-resonator.
H01S 3/042 - Arrangements for thermal management for solid state lasers
H01S 3/06 - Construction or shape of active medium
H01S 3/0941 - Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a semiconductor laser, e.g. of a laser diode
In one embodiment, an apparatus may include a first capillary component V(220). A second capillary component V(230) may be disposed outside of the first capillary component and may have an inner surface, wherein a portion of the inner surface may be heat- fused to an outer surface of the first capillary component. The apparatus may also include a portion of an optical fiber V(210) disposed inside of the first capillary component and the portion of the optical fiber can have an outer surface. A portion of the outer surface of the optical fiber may be heat-fused to an inner surface of the first capillary component. The optical fiber may have a distal surface (217) configured to reflect electromagnetic radiation propagated along a longitudinal axis of a distal end portion of the optical fiber in a lateral direction through the inner surface of the first capillary component and the inner surface of the second capillary component.
A61B 18/24 - Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibreHand-pieces therefor with a catheter
97.
METHODS AND APPARATUS RELATED TO A SIDE -FIRE MEMBER HAVING A DOPED SILICA COMPONENT
In one embodiment, an apparatus may include an optical fiber that may have a surface non-normal to a longitudinal axis of a distal end portion of the optical fiber. The surface may define a portion of an interface configured to redirect electromagnetic radiation propagated from within the optical fiber and incident on the interface to a direction offset from the longitudinal axis. The apparatus may also include a doped silica cap that may be fused to the optical fiber such that the surface of the optical fiber may be disposed within a cavity defined by the doped silica cap.
A61B 18/22 - Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibreHand-pieces therefor
98.
DIGITAL PULSE-WIDTH-MODULATION CONTROL OF A RADIO FREQUENCY POWER SUPPLY FOR PULSED LASER
A pulse width modulation method for controlling the output power of a pulsed gas discharge laser powered by a pulsed RF power supply comprises delivering a train of digital pulses to the RF power supply. Each pulse in the train has an incrementally variable duration. The power supply is arranged to deliver a train of RF pulses corresponding in number and duration to the train of digital pulses received. The average power in the RF-pulse train can be varied by incrementally varying the duration of one or more of the digital pulses in the digital pulse train. The train of RF pulses is used to power a gas discharge laser. The gas discharge laser outputs a pulse train corresponding to the RF pulse train.
H01S 3/097 - Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
H01S 3/102 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling the active medium, e.g. by controlling the processes or apparatus for excitation
H01S 3/223 - Gases the active gas being polyatomic, i.e. containing two or more atoms
An RF powered CO2 gas-discharge laser includes discharge electrodes and a lasing gas mixture between the electrode. The lasing gas mixture is ionized when the RF power is applied to the electrodes and laser action is initiated when the RF power has been applied for a duration sufficient to ignite a discharge in the lasing gas mixture. The gas mixture is pre- ionized by periodically applying the RF power to the electrodes for a predetermined period during which ignition of a discharge is not expected to occur. RF power reflected back from the electrodes is monitored. If the monitored power falls below a predetermined level indicative of the imminent onset of laser action before the predetermined duration has elapsed, application of the RF power to the electrodes is terminated to prevent the laser action from occurring.
Frequency-multiplied, Fiber master oscillator power amplifier (MOPA) apparatus includes one enclosure (12) containing a master oscillator and fiber amplifier stages and another enclosure (22) containing frequency-multiplying stages. Radiation is transmitted between the enclosures by a transport fiber in a flexible jacket (14) or enclosure. The transport fiber functions additionally as a power amplifier fiber, and amplifies the radiation while transporting the radiation between the enclosures. The amplifying transport fiber is energized by diode- lasers in the enclosure (12) containing the master oscillator and fiber amplifiers.
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