The invention discloses a method for measuring a complex degree of coherence of a random optical field by using a mutual intensity-intensity correlation, including the steps of: building a test optical path; rotating a quarter-wave plate to enable the fast axis of the quarter-wave plate to be consistent with a polarization direction of reference light, to obtain light intensity distribution information of a first combined light; rotating the quarter-wave plate to enable the slow axis of the quarter-wave plate to be consistent with the polarization direction of the reference light, to obtain light intensity distribution information of a second combined light; blocking the reference light to obtain light intensity distribution information of to-be-tested light; blocking the to-be-tested light to obtain light intensity distribution information of the reference light; and calculating the amplitude and phase of a complex degree of coherence of the to-be-tested light.

An optical system comprising an optical coherence tomography (OCT) measuring device and a beam deflection unit for laterally deflecting the position or angle of a beam path of the OCT measuring device. There is an optical component in the beam path, said optical component being embodied in such a way that a back-reflection of the optical component has a different configuration in terms of its longitudinal location along the beam path depending on the lateral position of the deflected beam path on the optical component. The optical system comprises an evaluation unit which is embodied in such a way that a value of the lateral position or angle deflection of the beam deflection unit is determinable on the basis of a longitudinal location of the back-reflection at the optical component determined by the OCT measuring device.

A laser interference device includes a measurement laser that outputs a laser beam, a beam splitter that divides the laser beam into a measurement laser beam and a frequency monitor laser beam, a reference laser that outputs a reference laser beam, a frequency detector that detects a beat frequency resulting from interference between the reference laser beam and the frequency monitor laser beam, a wavelength calculator that calculates a wavelength of the frequency monitor laser beam (a wavelength measurement value) on the basis of the beat frequency, a light detector that detects an interference light of the measurement light and the reference light of the measurement laser beam and outputs a light detection signal, and a displacement calculator that calculates a displacement of the measurement mirror by performing an arithmetic process based on the wavelength measurement value and the light detection signal.

The invention generally relates to methods for manually calibrating imaging systems such as optical coherence tomography systems. In certain aspects, an imaging system displays an image showing a target and a reference item. A user looks at the image and indicates a point within the image near the reference item. A processer detects an actual location of the reference item within an area around the indicated point. The processer can use an expected location of the reference item with the detected actual location to calculate a calibration value and provide a calibrated image. In this way, a user can identify the actual location of the reference point and a processing algorithm can give precision to the actual location.

A computer program product for numerically correcting an endpoint position of a Coordinate Measuring Machine (CMM) implemented on a computing unit, receiving as input temporally resolved information from a set of sensors attached to or integrated into the CMM, and to a method for numerically correcting an endpoint position of a CMM, wherein errors between a targeted endpoint position and an actual endpoint position reached during a measurement process are numerically compensated through the use of the computer program product.

Embodiments of systems and methods for measuring a surface topography of a semiconductor chip are disclosed. In an example, a method for measuring a surface topography of a semiconductor chip is disclosed. A plurality of interference signals each corresponding to a respective one of a plurality of positions on a surface of the semiconductor chip are received by at least one processor. The plurality of interference signals are transformed by the at least one processor into a plurality of spectrum signals each corresponding to the respective one of the positions on the surface of the semiconductor chip. The spectrum signals are classified by the at least one processor into a plurality of categories using a model. Each of the categories corresponds to a region having a same material on the surface of the semiconductor chip. A surface height offset between a surface baseline and at least one of the categories is determined by the at least one processor based, at least in part, on a calibration signal associated with the region corresponding to the at least one of the categories. The surface topography of the semiconductor chip is characterized by the at least one processor based, at least in part, on the surface height offset and the interference signals.

Embodiments of systems and methods for measuring a surface topography of a semiconductor chip are disclosed. In an example, a method for measuring a surface topography of a semiconductor chip is disclosed. A plurality of interference signals each corresponding to a respective one of a plurality of positions on a surface of the semiconductor chip are received by at least one processor. The interference signals are classified by the at least one processor into a plurality of categories using a model. Each of the categories corresponds to a region having a same material on the surface of the semiconductor chip. A surface height offset between a surface baseline and at least one of the categories is determined by the at least one processor based, at least in part, on a calibration signal associated with the region corresponding to the at least one of the categories. The surface topography of the semiconductor chip is characterized by the at least one processor based, at least in part, on the surface height offset and the interference signals.

Embodiments of systems for classifying interference signals are disclosed. In an example, a system for classifying interference signals includes an interferometer including a light source and a detector, and at least one processor. The interferometer is configured to provide a plurality of interference signals each corresponding to a respective one of a plurality of positions on a surface of a semiconductor chip. A spectrum of the light source is greater than a spectrum of white light. The at least one processor is configured to classify the interference signals into a plurality of categories using a model. Each of the categories corresponds to a region having a same material on the surface of the semiconductor chip.

Embodiments of systems and methods for measuring a surface topography of a semiconductor chip are disclosed. In an example, a method for measuring a surface topography of a semiconductor chip is disclosed. A plurality of interference signals and a plurality of spectrum signals are received by at least one processor. Each of the interference signals and spectrum signals corresponds to a respective one of a plurality of positions on a surface of the semiconductor chip. The spectrum signals are classified by the at least one processor into a plurality of categories using a model. Each of the categories corresponds to a region having a same material on the surface of the semiconductor chip. A surface height offset between a surface baseline and at least one of the categories is determined by the at least one processor based, at least in part, on a calibration signal associated with the region corresponding to the at least one of the categories. The surface topography of the semiconductor chip is characterized by the at least one processor based, at least in part, on the surface height offset and the interference signals.

An interferometer movable mirror position measurement apparatus for determining a position of a movable mirror of an interferometer. The interferometer movable mirror position measurement apparatus including: a laser light source; a phase separation optical system configured to make first light and second light separately detected; a signal conversion unit configured to detect the first light and the second light in synchronization with a position of a movable mirror to generate a first sinusoidal wave signal and a second sinusoidal wave signal, respectively; a phase calculation unit configured to perform normalization and phase difference correction on each of the first sinusoidal wave signal and the second sinusoidal wave signal, and then calculate a phase of the first sinusoidal wave signal or the second sinusoidal wave signal at each time point; and a movable mirror position determination unit configured to determine a position of the movable mirror at a predetermined time point.