A measurement method for interferometrically measuring the shape of a surface (112) of a test object (114). A test wave (125-1, 125-2) directed at the test object has a wavefront that is at least partially adapted to the desired shape of the surface, and a reference wave (128-1, 128-2) directed at a reflective optical element (130-1, 130 2) has a propagation direction that deviates from the propagation direction of the test wave (125-1, 125-2) for each of two input waves by diffraction at a diffractive element (124). For each wavelength, the test wave is superimposed after interaction with the test object with the associated reference wave after the back-reflection at the first reflective optical element. The test and reference waves are diffracted again at the diffractive element for superposition. An interferogram produced by the superposition is captured in a capture plane (148-1, 148-2). The interferograms are jointly evaluated.

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.

Exemplary apparatus and method are provided. In particular, an electromagnetic radiation can be emitted with, e.g. a light source arrangement. For example, the light source arrangement can include a cavity and a filter, and a spectrum of the electromagnetic radiation can be controlled, e.g., with such cavity and filter, to have a mean frequency that changes (i) at an absolute rate that is greater than about 100 terahertz per millisecond, and (ii) over a range that is greater than about 10 terahertz. Additionally or alternatively, the light source arrangement can include a frequency shifting device which can shift the mean frequency of the electromagnetic radiation.

An electro-optical system has a laser drive electronic circuit, a laser light source and an optical interferometer, forming a closed loop. The laser drive electronic circuit is arranged to receive a reference frequency as input, and a beat frequency as feedback. The laser drive electronic circuit generates a drive output based on a phase difference between the reference frequency and the beat frequency. The optical interferometer, coupled to the laser light, generates optical energy at the beat frequency.

A simultaneous phase-shift point diffraction interferometer and method for detecting wave aberration. The interferometer comprises an ideal spherical wave generation module, an optical system to be measured, an image plane mask, a polarization phase shift module, a two-dimensional polarization imaging photodetector and a data processing unit. Single photodetector is adopted to realize simultaneous detection of more than three phase shift interference patterns, and has the advantages that environmental interference suppression, a flexible optical path, high measurement accuracy, and calibration of system errors of the interferometer may be realized.

An exemplary system, method, and computer-accessible medium for generating an image(s) of an three-dimensional anatomical flow map(s) can include receiving an optical coherence tomography (“OCT”) signal(s), splitting the OCT signal(s) into a plurality of subspectra, averaging the plurality of subspectra, and generating the image(s) of the three-dimensional anatomical flow map(s) based on the averaged subspectra. The OCT signal(s) can be a swept-source OCT signal. The OCT signal(s) can be split into the subspectra based on a Hamming window. The Hamming distance window can be optimized to minimize a nearest side lobe for each of the subspectra. A position of at least one of the subspectra can be shifted prior to averaging the subspectra. The position of all but one of the subspectra can be shifted prior to averaging the subspectra.

The phase unwrapping device 10 includes coordinate transformation means 11 for transforming coordinates of a map including height information into SAR image coordinates, weight calculation means 12 for determining a place, from the map whose coordinates are transformed into the SAR image coordinate, where phase discontinuity may occur in a phase different image generated from two SAR images and attaching a weight to the place where it is determined that phase discontinuity may occur, and phase unwrapping means 13 for performing phase unwrapping for the phase difference image using the weight.

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.

Provided is an optical interference measuring apparatus including a measuring unit configured to acquire an interferogram of an interference wave by irradiating a measurement target and a reference surface with electromagnetic waves and causing a reflected wave from a reflecting surface of the measurement target to interfere with a reflected wave from the reference surface and a signal processing unit configured to configure an intensity profile in a depth direction by performing Fourier transform of the interferogram. The signal processing unit includes at least one of a first noise removal unit to remove noise with filtering by deleting data in regions other than a pass region which is a region set with reference to a measurement target installation position from the intensity profile and a second noise removal unit to remove noise by performing singular value decomposition of the interferogram to delete noise component.

In a general aspect, a method is presented for increasing the measurement precision of an optical instrument. The method includes determining, based on optical data and environmental data, a measured value of an optical property measured by the optical instrument. The optical instrument includes an optical path and a sensor configured to measure an environmental parameter. The method also includes determining a predicted value of the optical property based on a model representing time evolution of the optical instrument. The method additionally includes calculating an effective value of the optical property based on the measured value, the predicted value, and a Kalman gain. The Kalman gain is based on respective uncertainties in the measured and predicted values and defines a relative weighting of the measured and predicted values in the effective value.