A method for manufacturing an optical device includes: a laser irradiation step of condensing pulsed first laser light and pulsed second laser light to the inside of a glass member including germanium and titanium; and a condensing position movement step of moving condensing positions relatively to the glass member. Each of the first laser light and the second laser light has a repetition frequency of 10 kHz or greater. The first laser light is condensed to a dot-shaped condensing region, and the second laser light is condensed to an annular condensing region surrounding the condensing region of the first laser light. A central wavelength of the first laser light is greater than 400 nm and equal to or less than 700 nm, and a central wavelength of the second laser light is equal to or greater than 800 nm and equal to or less than 1100 nm.

In various embodiments, laser beams of two different wavelengths are utilized, sequentially and/or simultaneously, to process workpieces in various processing stages such as melting, piercing, cutting, and welding.

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 additive manufacturing device includes: an inner light beam radiation device of radiating an inner light beam; an outer light beam radiation device of radiating an outer light beam; and a control device. when a molten pool is irradiated with the outer light beam, the control device controls a power density of the outer light beam representing an output per unit area such that a cooling rate of the molten pool representing a temperature drop per unit time is 540 C./s or less at a freezing point of a carbide binder included in the molten pool, the molten pool being formed by irradiating a material including a hard material and a carbide binder with the inner light beam to melt the material. According to the present disclosure, the additive manufacturing device can prevent cracking and additively manufacture a high-quality shaped object with a simple configuration.

A laser processing method includes a step of irradiating a workpiece, in which a metal layer made of a heat-resistant alloy and a protective layer made of a thermal barrier coating are laminated, with a first laser beam that is a short-pulse laser beam, and forming a through-hole penetrating the metal layer, and a step of irradiating the workpiece with a laser beam to expand the through-hole.

The present disclosure relates to a laser system for processing a material. The system may make use of a laser configured to intermittently generate a first laser pulse of a first duration and a first average power, at a spot on a surface of the material being processed, and a second laser pulse having a second duration and a second peak power. The second duration may be shorter than the first duration by a factor of at least 100, and directed at the spot. The second laser pulse is generated after the first laser pulse is generated. The first laser pulse is used to heat the spot on the surface of the material, while the second laser pulse induces a melt motion and material ejection of molten material from the melt pool.

A laser oscillator includes a plurality of laser modules, beam coupler (12) that couples a plurality of laser beams (LB1 to LB4) emitted from the plurality of laser modules to form a coupled laser beam, beam coupler (12) emitting the coupled laser beam, and a condensing lens unit having a condensing lens, the condensing lens unit condensing the coupled laser beam to have a given beam diameter and guiding the condensed coupled laser beam to a transmission fiber. Beam coupler (12) has optical members (OC1 to OC4) configured to change optical paths of laser beams (LB1 to LB4). By changing the optical paths of laser beams (LB1 to LB4) by optical members (OC1 to OC4,) a beam profile of the coupled laser beam emitted from the transmission fiber is changed without adjusting a position of the condensing lens.

A laser machining device includes a plurality of oscillators to emit laser beams having different wavelengths from each other; a machining head to emit laser beams emitted from the respective oscillators to a machining object; a plurality of transmission fibers to transmit the laser beams to the machining head; a wavelength dispersion element; and a focusing lens to superpose the laser beams emitted from the transmission fibers, wherein the wavelength dispersion element is arranged at a position at which the laser beams are superposed by the focusing lens.

A thermal processing apparatus and method in which a first laser source, for example, a CO.sub.2 emitting at 10.6 m is focused onto a silicon wafer as a line beam and a second laser source, for example, a GaAs laser bar emitting at 808 nm is focused onto the wafer as a larger beam surrounding the line beam. The two beams are scanned in synchronism in the direction of the narrow dimension of the line beam to create a narrow heating pulse from the line beam when activated by the larger beam. The energy of GaAs radiation is greater than the silicon bandgap energy and creates free carriers. The energy of the CO.sub.2 radiation is less than the silicon bandgap energy so silicon is otherwise transparent to it, but the long wavelength radiation is absorbed by the free carriers.

A method for preparing a workpiece for separation is provided that includes providing a workpiece that is transparent for light of a pulsed laser beam, splitting the laser beam into two partial beams using an optical system, directing both partial beams onto the workpiece, and moving the workpiece and the partial beams relative to one another. The partial beams are directed onto the workpiece incident at different angles to the normal of the irradiated surface and superimposed inside the workpiece such that the partial beams interfere with one another to form a sequence of intensity maxima inside the workpiece. The intensity at the intensity maxima is sufficiently high to modify the material of the workpiece so that a chain-like periodic pattern of material modifications is formed along a path defining a separation line.