An interferometer system may include a stage assembly configured to receive and secure a sample, an illumination source configured to generate an illumination beam, a half-wave plate, one or more shearing prisms to shear the illumination beam into two beamlets along a shearing direction, a reference flat disposed proximate to the sample, a detector assembly, and a controller. The controller may cause the illumination source to generate an illumination beam and sweep the illumination beam across a plurality of wavelengths, and determine both a surface height measurement and a surface slope measurement of the sample based on the illumination received by the detector assembly.

A thickness measurement system may include an illumination source, a beam splitter to split illumination from the illumination source into two beams, a translation stage configured to translate a reference sample along a measurement direction, a first interferometer to generate a first interferogram between a first surface of a test sample and a first surface of the reference sample, and a second interferometer to generate a second interferogram between a second surface of the test sample and a second surface of the reference sample. A thickness measurement system may further include a controller to receive interference signals from the first and second interferometers as the translation stage scans the reference sample, and determine a thickness of the test sample based on the thickness of the reference sample and a distance travelled by the translation stage between peaks of envelopes of the interference signals.

A wear amount measuring apparatus includes a light source, a light transmission unit, a first and a second irradiation unit, a spectroscope and an analysis unit. The light transmission unit splits a low-coherence light from the light source into a first and a second low-coherence light. The first and the second irradiation units irradiate the first and the second low-coherence light to the component to receive reflected lights from the component. The light transmission unit transmits the reflected lights received by the first irradiation unit and the second irradiation unit to the spectroscope. The spectroscope configured to detect intensity distribution of the reflected lights from the first and the second irradiation unit. The analysis unit calculates a thickness difference between a thickness of the component at the first measuring point and that at the second measuring point by performing Fourier transform on the intensity distribution.

The present invention relates to a precision measurement system using an interferometer and an image, comprising: an interferometer for measuring a distance to a movable object by a transfer device; an imaging device which is fixed at a specific position and captures an image of an object located within a specific range; and a control device which calculates absolute coordinates indicating a distance from a reference point to each pixel of the image on the basis of the distance measured by the interferometer and the image obtained by the imaging device, calculates an absolute distance between the pixels of the image on the basis of the absolute coordinates, and measures a length of the object captured by the imaging device using the absolute coordinates or the absolute distance.

A laser tracking system for determining pose information of a rigid object is disclosed. The laser tracking system includes three or more retroreflectors, three or more sets of multiple laser trackers, and an electronic controller. Each retroreflector is secured to the rigid object that is moveable within a frame of reference. For each set of laser trackers, each laser tracker is configured to direct a laser beam to and receive a reflected laser beam from an associated one of the retroreflectors within the frame of reference. The electronic controller is in communication with each of the laser trackers and determines the pose information of the rigid object in the reference frame based on information about the fixed location of each laser tracker in the frame of reference and information about a distance of each retroreflector from each laser tracker of the set of laser trackers associated with the retroreflector.

According to an aspect of one or more embodiments, the present subject matter describes an apparatus for inspecting a slab of a material. The apparatus comprises a first and second low-coherence sensor configured to irradiate a first and second side of a slab of material with first light having a first polarization and second light having a second polarization, and thereafter configured to detect a reflection. A first polarizer is configured to allow reflected first light having the first polarization to pass through, and reject a second-light cross-talk portion having the second polarization. A second polarizer is configured to allow reflected second light having the second polarization to pass through, and reject a first-light cross-talk portion having the first polarization. Further, a computing-system is configured to receive signals representing the reflected first light and the reflected second light; and analyze the reflected first light and the reflected second light.

A shape measuring apparatus of the present invention measures a variation in a thickness of an object to be measured WA based on an A surface reference interference light and an A surface measuring interference light obtained by performing optical heterodyne interference on a first A surface measuring light and a second A surface measuring light and a B surface reference interference light and a B surface measuring interference light obtained by performing the optical heterodyne interference on a first B surface measuring light and a second B surface measuring light. When the optical heterodyne interference is performed, the shape measuring apparatus makes the first A surface measuring light and the second B surface measuring light equal in frequency and makes the first B surface measuring light and the second A surface measuring light equal in frequency.

A laser interferometer system includes a beam splitter to split a laser beam into first and second beam sets, a first retroreflector mounted to an object to reflect the first beam set, a first detecting device for detecting movements of the object in x-, y- and z-axis directions based on the reflected first beam set, a second retroreflector mounted to the object to reflect the second beam set, and a second detecting device for detecting rotations and movements of the object with respect to the y- and z-axis directions based on the reflected second beam set. The movements of the object in the z-axis direction obtained by the first and second detecting devices are used to obtain a rotation of the object with respect to the x-axis direction.

Inspecting a multilayer sample. In one example embodiment, a method may receiving, at a beam splitter, light and splitting the light into first and second portions; combining, at the beam splitter, the first portion of the light after being reflected from a multilayer sample and the second portion of the light after being reflected from a reflector; receiving, at a computer-controlled system for analyzing Fabry-Perot fringes, the combined light and spectrally analyzing the combined light to determine a value of a total power impinging a slit of the system for analyzing Fabry-Perot fringes; determining an optical path difference (OPD); recording an interferogram that plots the value versus the OPD for the OPD; performing the previous acts of the method one or more additional times with a different OPD; and using the interferogram for each of the different OPDs to determine the thicknesses and order of the layers of the multilayer sample.

Interferometric systems and methods for measuring rotational movement are described. In one implementation, an interferometer for measuring rotational movement includes a housing and a light source within the housing configured to project coherent light toward a non-coded surface of an object. The interferometer further includes at least one optical element configured to modify the projected coherent light in a manner accounting for a rotation of the object. The interferometer also includes at least one sensor within the housing including at least one light detector configured to detect reflections of the modified projected coherent light from the opposing non-coded surface as the object rotates relative to the housing. The interferometer further includes at least one processor configured to receive input from the at least one sensor and determine an amount of rotation of the object around the at least one rotational axis.