A method checks a focus position of a laser beam in relation to a workpiece. The method includes: focusing the laser beam at a plurality of positions along a trajectory on the workpiece; detecting radiation generated during an interaction of the laser beam with the workpiece at a respective position of the positions; determining signal values corresponding to the detected radiation at the respective position; and checking the focus position at at least one of the positions by comparing the respective one of the signal values at the respective position with a reference value formed from the signal values.

A method and system for detecting an operating condition of an optical element along a propagation path of a power laser beam in a laser processing machine head are based on a first signal of a back-propagating optical radiation at the wavelength of the laser beam; a second signal of a back-propagating optical radiation having a wavelength in the near infrared; a third signal of an optical radiation emitted by the optical element in the infrared in proximity to its surface; a fourth signal which is a function of the time-of-flight of an acoustic wave launched through the volume of the optical element.

A three dimensional printing system includes a laser system, a beam splitter, a pinhole, a sensor, and a controller. The laser system emits a light beam of varying diameter carrying at least 100 watts of optical power along an optical path. The laser has an imaging plane along the optical path which can be coincident or close to a focal plane at which the beam has a minimum diameter. The beam splitter is positioned along the optical path to receive the beam and to transmit most of the optical power and to reflect remaining optical power. The pinhole is positioned along the optical path at the imaging plane to receive the reflected beam having a minimal diameter. The controller is configured to analyze a signal from the sensor to determine intensity and distribution parameters for the light beam.

A laser oscillation device includes a laser oscillation unit, which is a laser oscillation part that generates multiple first laser beams having different wavelengths from one another, multiple sensors having different sensitivity characteristics from one another each representing light-receiving sensitivity for the wavelengths of the multiple first laser beams, to each output first voltages dependent on outputs of the multiple first laser beams. The laser oscillation device includes a computing unit that corrects the multiple first voltages using the sensitivity characteristics of the multiple sensors, and controls the laser oscillation unit based on multiple second voltages which correspond to multiple first voltages obtained after the correction.

A laser crystallizing apparatus includes a first light source unit configured to emit a first input light having a linearly polarized laser beam shape. A second light source unit is configured to emit a second input light having a linearly polarized laser beam shape. A polarization optical system is configured to rotate the first input light and/or the second input light at a predetermined rotation angle. An optical system is configured to convert the first input light and the second input light, which pass through the polarization optical system, into an output light. A target substrate is seated on a stage and output light is directed onto the target substrate. A monitoring unit is configured to receive the first input light or the second input light from the polarization optical system and measure a laser beam quality thereof.

There is provided a wafer for examination that is a wafer for examination with which energy distribution in a region of a light condensing spot of a laser beam with which irradiation is carried out from the upper surface side of a wafer is checked, and is a wafer for examination in which a first metal layer and a second metal layer different in specific heat or a melting point are formed over an upper surface of a wafer. In an examination method of energy distribution, the energy distribution of the laser beam is checked based on a processing mark formed in the first and second metal layers of the wafer for examination.

A laser machining device includes a reflective plate disposed perpendicular to the optical axis of emitting light and having a constant reflectance to the emitting light; a return light measurement unit which measures intensity distribution of return light reflected off the reflective plate and returning to the external optical system via a beam splitter; a storage unit which stores the return light intensity distribution in a normal state as reference data; a preprocessing unit which performs processing of identifying at least one of an optical axis shift, a beam diameter anomaly, a mode anomaly, a ghost, contamination of a protective window, and a focus shift due to thermal lens effect on the basis of comparison between measurement data of the return light intensity distribution and the reference data, before laser machining; and a warning unit which warns of an anomaly in the external optical system in accordance with the preprocessing unit.

A processing method for processing an SiC ingot includes a peel-off zone forming step of applying a processing pulsed laser beam having a wavelength transmittable through the ingot to the ingot while positioning a focused spot of the processing pulsed laser beam at a depth corresponding to a thickness of a wafer to be peeled off from the ingot, to form belt-shaped peel-off zones each including cracks in the ingot, a reflected beam detecting step of applying an inspecting laser beam having a wavelength transmittable through the ingot and reflectable from cracks of the peel-off zones and detecting an intensity of a beam reflected by the cracks, and a processing laser beam output power adjusting step of adjusting an output power of the processing pulsed laser beam to keep the intensity of the reflected beam detected in the reflected beam detecting step within a predetermined range.

A laser welding quality inspection method of a welded portion between a joining object and a joined object, when the joining object and the joined object are welded by being irradiated with a laser beam, the method includes: acquiring first data indicating a signal intensity of thermal radiation light radiated from the welded portion during the welding; acquiring second data indicating a signal intensity of plasma light radiated from the welded portion during the welding; and determining whether or not the welded portion includes an abnormality based on a comparison between the signal intensity of the thermal radiation light and the signal intensity of the plasma light which are acquired.

A laser system includes a controller comprising a processor and a non-transitory machine-readable memory, a laser head configured to output a laser beam, a work bed positioned opposite the laser head, and a power meter communicatively coupled to the electronic control unit and integrated within the work bed. The laser system further includes a knife edge plate positioned between the power meter and the laser head, and a machine-readable instruction set stored in the non-transitory machine readable memory that causes the laser system to perform at least the following when executed by the processor: position the laser head at a distance from the power meter, cause the laser head to output the laser beam, translate the laser head across the power meter, receive power signals from the power meter as the laser beam is translated across the power meter, and calculate a spot size based on the power signals.