A terminated hollow-core optical fiber includes a capillary, a hollow-core optical fiber including a structured cladding, and an endcap. A first end of the hollow-core optical fiber terminates inside the capillary a non-zero distance away from a first end face of the capillary. The hollow-core optical fiber is adhered to the capillary at a second end face of the capillary where the hollow-core optical fiber extends out of the capillary. The endcap is fused to the first end face of the capillary. The endcap has a larger diameter than the first end of the hollow-core optical fiber. This termination scheme does not require fusing the hollow-core fiber itself to the endcap or any other part. Therefore, this termination scheme is applicable to hollow-core fibers with a structured cladding that cannot tolerate the temperatures associated with fusing the hollow-core fiber to another part.
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 fiber-optic cable (100) includes an optical fiber (110) that transports a forward- propagating laser beam. The optical fiber includes a core (112), a cladding (114), and an output end-face (116) emitting the forward-propagating beam (190). The fiber-optic cable (100) also includes a mode-stripper (120), along a segment of the optical fiber (110), that couples out backward-propagating radiation (194) that has been coupled into the cladding (114) at the output end-face (116). The fiber-optic cable (100) further includes a waveguide (130) having a waveguide body (132) with a bore (134) containing at least part of the segment of the optical fiber (110). The bore (132) is defined by an inward-facing surface (138) that guides at least a fraction of the backward-propagating radiation (194), coupled out of the cladding (114) by the mode-stripper (120), toward a rear opening of the bore (134) farthest from the output end-face (116). Additionally, the fiber-optic cable (100) includes one or more sensors (150) or fiber ports that receive portions of the backward-propagating radiation (194) emerging from the rear opening.
A fiber-optic cable includes an optical fiber that transports a forward-propagating laser beam. The optical fiber includes a core, a cladding, and an output end-face emitting the forward-propagating beam. The fiber-optic cable also includes a mode-stripper, along a segment of the optical fiber, that couples out backward-propagating radiation that has been coupled into the cladding at the output end-face. The fiber-optic cable further includes a waveguide having a waveguide body with a bore containing at least part of the segment of the optical fiber. The bore is defined by an inward-facing surface that guides at least a fraction of the backward-propagating radiation, coupled out of the cladding by the mode-stripper, toward a rear opening of the bore farthest from the output end-face. Additionally, the fiber-optic cable includes one or more sensors or fiber ports that receive portions of the backward-propagating radiation emerging from the rear opening.
The invention concerns an apparatus and its use for laser welding. A laser welding apparatus comprise at least one first laser device, each providing at least one first optical feed fiber with a first laser beam; at least one second laser device, each providing at least one second optical feed fiber with a second laser beam; means for generating a composite laser beam comprising a first output laser beam and a second output laser beam for welding a workpiece; wherein the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to the first output laser beam. The second laser device is a fiber laser device or a fiber-coupled laser device. The apparatus is configured to form the second output laser beam at least on the basis of the second laser beam, and the second output laser beam comprises a first wavelength and a second wavelength having difference of at least 10 nanometers, or the second output laser beam has spectrum width of least 10 nanometers.
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 terminated hollow-core optical fiber (100) includes a capillary (120), a hollow-core optical fiber (110) including a structured cladding, and an endcap (130). A first end of the hollow-core optical fiber (110) terminates inside the capillary (120) a non-zero distance away from a first end face (122) of the capillary (120). The hollow-core optical fiber (110) is adhered to the capillary (120) at a second end face (124) of the capillary (120) where the hollow-core optical fiber (110) extends out of the capillary (120). The endcap (130) is fused to the first end face (122) of the capillary (120). The endcap (130) has a larger diameter than the first end of the hollow-core optical fiber (110). This termination scheme does not require fusing the hollow-core fiber itself to the endcap (130) or any other part. Therefore, this termination scheme is applicable to hollow-core fibers with a structured cladding that cannot tolerate the temperatures associated with fusing the hollow-core fiber to another part.
A terminated hollow-core optical fiber includes a capillary, a hollow-core optical fiber including a structured cladding, and an endcap. A first end of the hollow-core optical fiber terminates inside the capillary a non-zero distance away from a first end face of the capillary. The hollow-core optical fiber is adhered to the capillary at a second end face of the capillary where the hollow-core optical fiber extends out of the capillary. The endcap is fused to the first end face of the capillary. The endcap has a larger diameter than the first end of the hollow-core optical fiber. This termination scheme does not require fusing the hollow-core fiber itself to the endcap or any other part. Therefore, this termination scheme is applicable to hollow-core fibers with a structured cladding that cannot tolerate the temperatures associated with fusing the hollow-core fiber to another part.
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
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.
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 3/042 - Arrangements for thermal management for solid state lasers
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
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
Laser welding methods include focusing laser radiation onto a first metal sheet disposed on a metal part, optionally with one or more intervening metal sheets therebetween. The laser radiation is steered to trace at least one spiral path to spot-weld together the metal parts. The laser radiation includes a center beam and an annular beam to maintain a stable keyhole. One method is tailored to weld aluminum parts, e.g., with high gas content and/or dissimilar compositions, and the laser radiation traces first an outward spiral path and then an inward spiral path. The center beam is pulsed during one segment of the inward spiral path. Another method is tailored to weld steel or copper parts having a coating at an interface therebetween, and the laser radiation traces an inward spiral path. The interface may be a zero-gap interface, or a non-zero gap may exist.
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
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.
Laser welding methods include focusing laser radiation (120) onto a first metal sheet (112) disposed on a metal part (114), optionally with one or more intervening metal sheets therebetween. The laser radiation (120) is steered to trace at least one spiral path to spot-weld together the metal parts (114). The laser radiation (120) includes a center beam (122C) and an annular beam (122A) to maintain a stable keyhole. One method is tailored to weld aluminum parts, e.g., with high gas content and/or dissimilar compositions, and the laser radiation (120) traces first an outward spiral path (810) and then an inward spiral path (830). The center beam (122C) is pulsed during one segment of the inward spiral path (830). Another method is tailored to weld steel or copper parts having a coating at an interface therebetween, and the laser radiation (120) traces an inward spiral path (830). The interface (414F) may be a zero- gap interface, or a non-zero gap may exist.
Laser welding methods include focusing laser radiation (120) onto a first metal sheet (112) disposed on a metal part (114), optionally with one or more intervening metal sheets therebetween. The laser radiation (120) is steered to trace at least one spiral path to spot-weld together the metal parts (114). The laser radiation (120) includes a center beam (122C) and an annular beam (122A) to maintain a stable keyhole. One method is tailored to weld aluminum parts, e.g., with high gas content and/or dissimilar compositions, and the laser radiation (120) traces first an outward spiral path (810) and then an inward spiral path (830). The center beam (122C) is pulsed during one segment of the inward spiral path (830). Another method is tailored to weld steel or copper parts having a coating at an interface therebetween, and the laser radiation (120) traces an inward spiral path (830). The interface (414F) may be a zero- gap interface, or a non-zero gap may exist.
A system (100) for nonlinear frequency conversion includes an acousto- optic modulator (110) for diffracting a portion of an input laser beam (190) as a first-order beam (192(1)) and transmitting a non-diffracted portion of the input laser (190) beam as a zeroth-order beam (192(0)). The system (100) also includes a nonlinear crystal (120) arranged to receive and frequency convert each of the zeroth-order (192(0)) and first-order (192(1)) beams to generate two respective frequency-converted laser beams (198(0),198(1)), whereby, when the acousto-optic modulator (110) changes the average-power ratio between the zeroth-order (192(0)) and first-order (192(1)) beams, variations of the heat load in the nonlinear crystal (120) are minimized. Either one of the two frequency-converted laser beams (198(0),198(1)) may be used as an output laser beam of the system (100), while the other one of the two frequency-converted laser beams (198(0),198(1)) serves to stabilize the heat load in the nonlinear crystal (120) when the acousto-optic modulator (110) is operated to change the average power in the output 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 modulating; Non-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
Laser welding methods include focusing laser radiation onto a first metal sheet disposed on a metal part, optionally with one or more intervening metal sheets therebetween. The laser radiation is steered to trace at least one spiral path to spot-weld together the metal parts. The laser radiation includes a center beam and an annular beam to maintain a stable keyhole. One method is tailored to weld aluminum parts, e.g., with high gas content and/or dissimilar compositions, and the laser radiation traces first an outward spiral path and then an inward spiral path. The center beam is pulsed during one segment of the inward spiral path. Another method is tailored to weld steel or copper parts having a coating at an interface therebetween, and the laser radiation traces an inward spiral path. The interface may be a zero-gap interface, or a non-zero gap may exist.
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 optomechanical assembly for temperature-robust laser beam processing includes a baseplate and an optics plate. The baseplate includes a source area for accommodating a source of the laser beam, and a light-processing area located away from the source area and including first and second anchor points. The optics plate is disposed in the light-processing area and includes first and second portions and a flexible coupling 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 series of optical elements for manipulating a laser beam from the laser source. Each of the optical elements is rigidly bonded to the first portion.
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.
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 system for nonlinear frequency conversion includes an acousto-optic modulator for diffracting a portion of an input laser beam as a first-order beam and transmitting a non-diffracted portion of the input laser beam as a zeroth-order beam. The system also includes a nonlinear crystal arranged to receive and frequency convert each of the zeroth-order and first-order beams to generate two respective frequency-converted laser beams, whereby, when the acousto-optic modulator changes the average-power ratio between the zeroth-order and first-order beams, variations of the heat load in the nonlinear crystal are minimized. Either one of the two frequency-converted laser beams may be used as an output laser beam of the system, while the other one of the two frequency-converted laser beams serves to stabilize the heat load in the nonlinear crystal when the acousto-optic modulator is operated to change the average power in the output laser beam.
G02F 1/37 - Non-linear optics for second-harmonic generation
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 modulating; Non-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
A multipass laser amplifier (100) includes a mirror (130), a mirror device (140), a gain crystal (120), and refractive or diffractive beam-steering element (110). The gain crystal (120) is positioned on a longitudinal axis of the multipass laser amplifier (100) between the mirror (130) and the mirror device (140). The beam-steering element (110) is positioned on the longitudinal axis between the gain crystal (120) and the mirror device (140). The beam-steering element (110) has no optical power and deflects a laser beam, by refraction or diffraction, for each of multiple passes of the laser beam between the first mirror (130) and the mirror device (140), such that each pass goes through the gain crystal (120) for amplification of the laser beam and goes through a different respective off-axis portion of the beam-steering element (110). The no optical power of the beam-steering element (110) enables maintaining a large beam size in the gain crystal (120), thereby facilitating amplification to high average power.
A multipass laser amplifier includes a mirror, a mirror device, a gain crystal, and refractive or diffractive beam-steering element. The gain crystal is positioned on a longitudinal axis of the multipass laser amplifier between the mirror and the mirror device. The beam-steering element is positioned on the longitudinal axis between the gain crystal and the mirror device. The beam-steering element has no optical power and deflects a laser beam, by refraction or diffraction, for each of multiple passes of the laser beam between the first mirror and the mirror device, such that each pass goes through the gain crystal for amplification of the laser beam and goes through a different respective off-axis portion of the beam-steering element. The no optical power of the beam-steering element enables maintaining a large beam size in the gain crystal, thereby facilitating amplification to high average power.
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 3/11 - Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
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
30.
PULSED LASER WITH INTRACAVITY FREQUENCY CONVERSION AIDED BY EXTRA-CAVITY FREQUENCY CONVERSION
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 locking; Q-switching; Other 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
31.
LASER WELDING OF METAL PIN PAIRS WITH TIME-DEPENDENT SCAN PATTERN AND ENERGY INPUT
A method for laser welding a pair of metal pins delivers a laser beam to a work-side of the pair of metal pins where a respective pair of surfaces of the metal pins are adjacent to each other and face in the same direction. The laser beam first traces a first path on the work-side to form a melt pool by keyhole welding. The first path crosses an interface between the metal pins. After tracing the first path, the laser beam is switched to trace a second path on the work-side with the laser beam at a delivered rate of energy per unit path length that is less than the one used for the first path. The second path crosses the interface and is within the first path. The method is well-suited for welding of hairpin and I-pin stators.
A method for laser welding a pair of metal pins (182,200) delivers a laser beam (112) to a work-side (220) of the pair of metal pins (182,200) where a respective pair of surfaces (204) of the metal pins (182,200) are adjacent to each other and face in the same direction. The laser beam (112) first traces a first path (230,630) on the work-side (220) to form a melt pool (850)by keyhole welding. The first path (230,630) crosses an interface (210) between the metal pins (182,200). After tracing the first path (230,630), the laser beam (112) is switched to trace a second path (240,640) on the work-side (220) with the laser beam (112) at a delivered rate of energy per unit path length that is less than the one used for the first path (230,630). The second path (240,640) crosses the interface (210) and is within the first path (230,630). The method is well-suited for welding of hairpin and I-pin stators.
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 is reduced, motion of the focused beams is stopped, the power of the center beam 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.
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.
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.
A method for laser keyhole welding a stack of metal foils (22) to a metal tab (24) is disclosed. The method independently adjusts power in a focused center beam and power in a focused annular beam to form a weld (34) through all the foils (22) and the tab (24). The annular beam provides sufficient power to heat the metal to about melting temperature, widen a mouth of a keyhole, and stabilize a melt pool. The center beam provides sufficient additional power to form the keyhole. The power of the annular beam is sustained for a longer time than the power of the center beam. A plurality of such welds is formed to provide mechanical strength and electrical conductivity.
A method for laser keyhole welding a stack of metal foils to a metal tab is disclosed. The method independently adjusts power in a focused center beam and power in a focused annular beam to form a weld through all the foils and the tab. The annular beam provides sufficient power to heat the metal to about melting temperature, widen a mouth of a keyhole, and stabilize a melt pool. The center beam provides sufficient additional power to form the keyhole. The power of the annular beam is sustained for a longer time than the power of the center beam. A plurality of such welds is formed to provide mechanical strength and electrical conductivity.
A method for laser keyhole welding a stack of metal foils (22) to a metal tab (24) is disclosed. The method independently adjusts power in a focused center beam and power in a focused annular beam to form a weld (34) through all the foils (22) and the tab (24). The annular beam provides sufficient power to heat the metal to about melting temperature, widen a mouth of a keyhole, and stabilize a melt pool. The center beam provides sufficient additional power to form the keyhole. The power of the annular beam is sustained for a longer time than the power of the center beam. A plurality of such welds is formed to provide mechanical strength and electrical conductivity.
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
2) 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.
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.
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.
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
A fiber laser producing a beam of ultrashort laser pulses at a repetition rate greater than 200 MHz includes a linear fiber resonator and a fiber branch. Ultrashort laser pulses are generated by passive mode-locking and circulate within the linear fiber resonator. Each circulating laser pulse is split into a portion that continues propagating in the linear fiber resonator and a complementary portion that propagates through the fiber branch and is then returned to the linear fiber resonator. The optical length of the linear fiber resonator is an integer multiple of the optical length of the fiber branch. The repetition rate of the ultrashort laser pulses is the reciprocal of the propagation time of the laser pulses through the fiber branch.
H01S 3/08 - Construction or shape of optical resonators or components thereof
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/1055 - 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 one of the reflectors being constituted by a diffraction grating
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.
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 pump reflector (10) for efficiently recycling unabsorbed pump radiation in a diode-pumped fiber laser includes a core (12) for guiding a laser beam, a pump cladding (14), and a tapered capillary tube (16). Pump radiation is adiabatically guided in the tapered capillary tube (16), which includes a mirror (28) that is reflective for the pump radiation. The pump reflector (10) may be packaged as a fiber component for copropagating or counter-propagating fiber laser amplifiers and resonators.
The invention concerns an apparatus and its use for laser welding. A laser welding apparatus comprise at least one first laser device, each providing at least one first optical feed fiber with a first laser beam; at least one second laser device, each providing at least one second optical feed fiber with a second laser beam; means for generating a composite laser beam comprising a first output laser beam and a second output laser beam for welding a workpiece; wherein the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to the first output laser beam. The second laser device is a fiber laser device or a fiber-coupled laser device. The apparatus is configured to form the second output laser beam at least on the basis of the second laser beam, and the second output laser beam comprises a first wavelength and a second wavelength having difference of at least 10 nanometers, or the second output laser beam has spectrum width of least 10 nanometers.
The invention relates to an optical assembly (100) comprising a first optical fiber (101) propagating coherent light in a predetermined direction (P) into an input end (110) of the optical assembly (100), said optical fiber having a core and a cladding; a heat sink (111) surrounding the optical fiber (101) at the input end (110); and a lens (120) arranged after the heat sink (111) in the propagating direction (P). The optical assembly (100) further comprises a filter (130) arranged after the lens (120), wherein the filter (130) has a reflective surface (131) arranged to transmit light having one or more desired wavelengths and to reflect one or more undesired wavelengths back through the lens (120). The invention further relates to a method for separating desired and undesired wavelengths.
G02B 6/42 - Coupling light guides with opto-electronic elements
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
G02B 6/32 - Optical coupling means having lens focusing means
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.
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.
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.
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.
B23K 26/00 - Working by laser beam, e.g. welding, cutting or boring
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 26/066 - 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 26/0622 - Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
B23K 26/08 - Devices involving relative movement between laser beam and workpiece
B23K 26/402 - Removing material taking account of the properties of the material involved involving non-metallic material, e.g. isolators
C03B 33/02 - Cutting or splitting sheet glass; Apparatus or machines therefor
G02B 27/09 - Beam shaping, e.g. changing the cross-sectioned area, not otherwise provided for
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.
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.
H01S 3/06 - Construction or shape of active medium
H01S 3/115 - Q-switching using intracavity electro-optic devices
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
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 26/354 - Working by laser beam, e.g. welding, cutting or boring for surface treatment by melting
B23K 26/00 - Working by laser beam, e.g. welding, cutting or boring
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.
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 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.
G01J 1/42 - Photometry, e.g. photographic exposure meter using electric radiation detectors
H01L 31/0368 - SEMICONDUCTOR DEVICES NOT COVERED BY CLASS - Details thereof characterised by their semiconductor bodies characterised by their crystalline structure or particular orientation of the crystalline planes including polycrystalline semiconductors
G01J 5/12 - Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using thermoelectric elements, e.g. thermocouples
A pump reflector for efficiently recycling unabsorbed pump radiation in a diode-pumped fiber laser includes a core for guiding a laser beam, a pump cladding, and a tapered capillary tube. Pump radiation is adiabatically guided in the tapered capillary tube, which includes a mirror that is reflective for the pump radiation. The pump reflector may be packaged as a fiber component for co-propagating or counter-propagating fiber laser amplifiers and resonators.
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.
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, which includes a plurality of mirrors, a polarization-selective reflector, and a polarization rotator, causes plane-polarized fundamental-wavelength radiation being converted to make two passes through the crystals in orthogonally-opposed polarization orientations.
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 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 3/106 - 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
The invention concerns an apparatus and its use for laser processing. The invention also concerns a method and an optical component. According to the invention, at a first laser device, providing a first optical feed fiber and a second laser device providing a second optical feed fiber is provided. A beam combining means connected to the first and second feed fibers and to a multi-core optical fiber is adapted to form a composite laser beam by having the first optical feed fiber aligned with a first core of the multi-core optical fiber and the second optical feed fiber aligned with at least one second core of the multi-core optical fiber. The first and second cores outputs a composite laser beam to a workpiece to be processed. A control unit controls power density of at least one of first and second laser beams of the composite laser beam in at least one of: in response to approaching a change point in direction of cutting progression and to cause change in relation between the power density of the first output laser beam and power density of the second output laser beam in accordance with thickness of the workpiece being cut.
B23K 26/38 - Removing material by boring or cutting
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
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.
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 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.
B23K 26/06 - Shaping the laser beam, e.g. by masks or multi-focusing
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 26/356 - Working by laser beam, e.g. welding, cutting or boring for surface treatment by shock processing
B23K 26/359 - Working by laser beam, e.g. welding, cutting or boring for surface treatment by providing a line or line pattern, e.g. a dotted break initiation line
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
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 27/14 - Beam splitting or combining systems operating by reflection only
G02B 13/14 - Optical objectives specially designed for the purposes specified below for use with infrared or ultraviolet radiation
G02B 27/18 - Optical systems or apparatus not provided for by any of the groups , for optical projection, e.g. combination of mirror and condenser and objective
G02B 23/04 - Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices involving prisms or mirrors for the purpose of beam splitting or combining, e.g. fitted with eyepieces for more than one observer
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 27/09 - Beam shaping, e.g. changing the cross-sectioned area, not otherwise provided for
The invention concerns an apparatus and its use for laser welding. A laser welding apparatus comprises at least one first laser device (30), each providing at least one first optical feed fiber (32) with a first laser beam; at least one second laser device (31), each providing at least one second optical feed fiber (33) with a second laser beam; means for generating a composite laser beam comprising a first output laser beam and a second output laser beam (2) for welding a workpiece (21); wherein the first output laser beam has a circular cross-section and the second output laser beam (2) has an annular shape concentric to the first output laser beam. The second laser device (31) is a fiber laser device or a fiber-coupled laser device. The apparatus is configured to form the second output laser beam (2) at least on the basis of the second laser beam, and the second output laser beam (2) comprises a first wavelength and a second wavelength having difference of at least 10 nanometers, or the second output laser beam (2) has spectrum width of least 10 nanometers.
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.
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.
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.
B23K 26/04 - Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
G01B 7/14 - Measuring arrangements characterised by the use of electric or magnetic techniques for measuring distance or clearance between spaced objects or spaced apertures
B23K 26/38 - Removing material by boring or cutting
The invention concerns an apparatus and a method for laser processing. There is provided at least one first laser beam from at least one first optical feed fiber connected to at least one first laser device and at least one second laser beam from at least one second optical feed fiber connected to at least one second laser device. Said first and second laser beams are combined in a multi-core optical fiber. Said first core of said multi-core optical fiber has a circular cross-section, and said second core has an annular shape concentric to said first core. A composite laser beam comprising first and second output beams is directed from said multi-core optical fiber to a workpiece with overlapping elements to be welded.
The invention relates to an optical assembly (100) comprising a first optical fiber (101) propagating coherent light in a predetermined direction (P) into an input end (110) of the optical assembly (100), said optical fiber having a core and a cladding; a heat sink (111) surrounding the optical fiber (101) at the input end (110); and a lens (120) arranged after the heat sink (111) in the propagating direction (P).The optical assembly (100) further comprises a filter (130) arranged after the lens (120), wherein the filter (130) has a reflective surface (131) arranged to transmit light having one or more desired wavelengths and to reflect one or more undesired wavelengths back through the lens (120). The invention further relates to a method for separating desired and undesired wavelengths.
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
80.
High power sub-400 femtosecond MOPA with solid-state power amplifier
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.
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.
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 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.
H01S 3/10 - Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
H01S 3/109 - Frequency multiplication, e.g. harmonic generation
H01S 3/081 - Construction or shape of optical resonators or components thereof comprising three or more reflectors
H01S 3/13 - Stabilisation of laser output parameters, e.g. frequency or amplitude
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
The invention concerns an apparatus and its use for laser processing. The invention also concerns a method. According to the invention, at a first laser device (30), providing a first optical feed fiber (32) and at a second laser device (31 ) providing a second optical feed fiber (33). A beam combining means (34) connected to the first and second feed fibers and to a multi-core optical fiber (35) is adapted to form a composite laser beam by having the first optical feed fiber (32) aligned with a first core of the multi-core optical fiber and the second optical feed fiber aligned with at least one second core of the multi-core optical fiber (35). The first and second cores output a composite laser beam (2) to a workpiece (21) to be processed. A control unit (10) controls power density of at least one of first and second laser beams of the composite laser beam in at least one of: in response to approaching a change point (22) in direction of cutting progression and to cause change in relation between the power density of the first output laser beam and power density of the second output laser beam in accordance with thickness of the workpiece (21) being cut.
G02B 6/04 - Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres
85.
Laser processing apparatus and method and an optical component therefor
An apparatus and its use for laser processing along with a method and an optical component. A first laser device provides a first optical feed fiber and a second laser device provides a second optical feed fiber. A beam combining means connected to the first and second feed fibers and to a multi-core optical fiber is adapted to form a composite laser beam by having the first optical feed fiber aligned with a first core of the multi-core optical fiber and the second optical feed fiber aligned with at least one second core of the multi-core optical fiber. The first and second cores outputs a composite laser beam to a workpiece to be processed. A control unit individually controls the power density of the output laser beams.
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
86.
LASER APPARATUS FOR CUTTING BRITTLE MATERIAL WITH ASPHERIC FOCUSING MEANS AND A BEAM EXPANDER
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
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.
B23K 26/00 - Working by laser beam, e.g. welding, cutting or boring
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 26/066 - 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 26/0622 - Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
B23K 26/08 - Devices involving relative movement between laser beam and workpiece
B23K 26/402 - Removing material taking account of the properties of the material involved involving non-metallic material, e.g. isolators
C03B 33/02 - Cutting or splitting sheet glass; Apparatus or machines therefor
G02B 27/09 - Beam shaping, e.g. changing the cross-sectioned area, not otherwise provided for
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 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 radiation; Arrangements 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
Apparatus (10) for generating ultraviolet (UV) pulsed laser-radiation for material-processing includes a laser-source (20) providing infrared (IR) pulsed laser-radiation and a frequency-conversion module (28). A lithium tetraborate (Li2B4O7) crystal (72) located within the frequency-conversion module (28) converts the IR pulsed laser-radiation to UV pulsed laser-radiation by non-linear harmonic generation. The frequency-conversion module (28) is an airtight enclosure that may be evacuated or contain a dry gas. A flexible optical fiber-assembly (24) transports the IR pulsed laser-radiation from the laser-source to the frequency-conversion module.
7) crystal located within the frequency-conversion module converts the IR pulsed laser-radiation to UV pulsed laser-radiation by non-linear harmonic generation. The frequency-conversion module is an airtight enclosure that may be evacuated or contain a dry gas. A flexible optical fiber-assembly transports the IR pulsed laser-radiation from the laser-source to the frequency-conversion module.
G02B 26/08 - Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
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.
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 impact; Aligning, 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 modulating; Non-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
95.
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
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
G02B 13/00 - Optical objectives specially designed for the purposes specified below
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
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 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.
In pulsed-laser apparatus for filamentary cutting a glass-sheet, a laser-beam is focused by a plano-convex focusing lens into the glass-sheet through a first surface of the sheet to a point close to a second surface of the sheet. Pulses from the laser are delivered in repeated bursts. The laser-beam fills the clear-aperture of the lens such that uncorrected spherical aberration in the focusing lens causes radial modulation of the beam between the lens and the focus point. This provides that each burst of pulses generates a filament extending between the first and second surfaces of the sheet.