An acousto-optic modulator (AOM) laser frequency shifter system includes a laser configured to generate an incident beam, a first optical splitter optically coupled to the laser and configured to split the incident beam into at least one portion of the incident beam, at least one phase-shift channel optically coupled to the first optical splitter and configured to generate at least one frequency-shifted beam with an acousto-optic modulator (AOM) from the at least one portion of the incident beam received from the first optical splitter, and a second optical splitter configured to receive the at least one frequency-shifted beam from the at least one phase-shift channel and configured to direct the at least one frequency-shifted beam to an interferometer configured to acquire an interferogram of a sample with the at least one frequency-shifted beam.

In a method for characterizing the surface shape, the following steps are carried out iteratively: (A) calculating a first figure based on first measurements; (B) subtracting the first figure from first measured values, to determine a first test set-up error; (C) using the first test set-up error for calculating a corrected first figure,; (D) subtracting the corrected first figure from second measured values, to determine a second test set-up error; (E) using the second test set-up error for calculating a corrected second figure; (F) using the corrected second figure for correcting the first test set-up error by subtracting the corrected second figure from the first measured values, to determine a corrected first test set-up error; (G) using the corrected first test set-up error for calculating a first figure corrected once again; and (H) comparing the result with a convergence criterion and optionally repeating steps (A) to (H).

Systems and methods for measuring a surface topography of a semiconductor chip are disclosed. A disclosed system comprises a light source configured to provide low coherent light to a first beam splitter, a scanner configured to use the low coherent light reflected from the first beam splitter to scan positions on a surface of a semiconductor chip, a second beam splitter configured to receive reflected signals from the positions on the surface of the semiconductor chip, a detector configured to detect interference signals from a first output of the second beam splitter, wherein each of the interference signals corresponds to a respective one of the positions, and a spectrometer configured to detect spectrum signals from a second output of the second beam splitter, wherein each of the spectrum signals corresponds to the respective one of the positions.

A method for monitoring and/or controlling in a closed loop a laser welding process for welding together two workpieces of metallic material includes, during the laser welding process, scanning a melt pool and/or a melt bead using an optical coherence tomography (OCT) measurement beam in at least one line scan, determining an actual geometry of the melt pool and/or the melt bead based on the at least one line scan, and setting at least one welding parameter controlled in the closed loop based on a deviation of the actual geometry from a target geometry of the melt pool and/or the melt bead.

A three-dimensional measurement device includes: an irradiator that emits a predetermined light; an optical system that splits the predetermined light into two lights, irradiates a measurement object with a measurement light and irradiates a reference plane with a reference light, and emits a combined light; an imaging device that takes an image of the combined light and obtains an interference fringe image; an objective lens for the measurement light that directs the measurement light toward the measurement object; an objective lens for the reference light that directs the reference light toward the reference plane; an imaging lens that forms an image of the combined light on the imaging device; and a control device that executes three-dimensional measurement of a measurement area on the measurement object based on the interference fringe image.

A method performs phase shift interferometry to detect irregularities of a surface of a wafer after the wafer has been placed into an interferometer and while the wafer is vibrating. Additionally, a system and a non-transitory computer-readable storage medium have computer-executable instructions embodied thereon for performing phase shift interferometry to detect irregularities of a surface of a wafer after the wafer has been placed into an interferometer and while the wafer is vibrating.

A displacement sensor includes a radiation part that irradiates a workpiece displaceable in a predetermined displacement direction with light, a light receiving part that receives a reflected light generated when the light radiated by the radiation part is reflected on the workpiece, and a fringe generation part that includes a generation means for generating fringes on a light receiving surface of the light receiving part when the light receiving part receives the reflected light from the workpiece. The fringe generation part and the light receiving part are arranged such that the fringe generation part and the light receiving part are parallel to the displacement direction, or parallel to a virtual image of the displacement direction.

The present invention provides an interference measuring device with an optical system that can receive light reflected from a measurement object of a surface profile that is not perpendicular to an optical axis. An interference measuring device includes a light source for emitting light and an interferometric objective lens. The interferometric objective lens includes a reference mirror disposed in a reference beam path and a beam splitter that splits the incident light into a beam traveling along the reference beam path and a beam traveling along a measurement beam path. The beam splitter also combines the beam reflected off the reference mirror with the beam reflected off a measurement object disposed in the measurement beam path before emitting the combined beams. The interference measuring device further includes an imaging unit for taking an image of the combined beams forming on the unit and an aperture stop disposed in an optical path linking the interferometric objective lens, the light source, and the imaging unit together. The aperture stop is movable along an optical axis of the interferometric objective lens.

A calibration method of an optical coherence tomography (OCT) device and a camera using the same target includes irradiating a shape measurement light to a calibration target, obtaining a surface shape image thereof by detecting light reflected by a surface of the calibration target using a shape measurement camera, and calibrating the surface shape image according to an actual shape of the calibration target; obtaining surface and internal three-dimensional images of the calibration target by scanning with a layer measurement light using the OCT measurement unit, extracting a surface shape image of the calibration target from the three-dimensional images, and calibrating the surface shape image according to the actual surface shape of the calibration target; and matching a calibration image obtained by the shape measurement camera and a surface calibration image obtained by the OCT measurement unit to be displayed at the same spatial coordinates.

An optical measuring probe for measuring inner and/or outer diameters of objects, uses a first optical element for focusing or collimating an optical beam onto a surface of an object. A second optical element for splitting the optical beam into a first measuring beam and a second measuring beam is provided in the optical measuring probe in such a way that the second measuring beam is guided out of the measuring probe in a direction opposite the direction of the first measuring beam and that the first measuring beam forms a first scan point and the second measuring beam forms a second scan point. Also described is a corresponding method for measuring diameters using the optical measuring probe. The optical measuring probe and the associated method make it possible to optically measure inner and outer diameters of measuring probes objects in a simple manner.