A transient digital moire phase-shifting interferometric measuring device and method for a surface shape of an optical element solves a defect that an instantaneous vibration resistance needs to be sacrificed for a measurement range when using a two-step carrier splicing method, and expands the measurement range of a digital moire phase-shifting method while retaining instantaneous anti vibration characteristics of the digital moire phase-shifting method. The transient digital moire phase-shifting interferometric measuring device includes a light source, a beam splitter, a reference lens, a first polarization grating, a measured lens, a second polarization grating, a first imaging objective lens, a first camera, a second imaging objective lens and a second camera. Different carriers are loaded through a spectral performance of a polarization grating, and the polarization grating is used to separate two beams of an interference light, and two actual interference patterns are obtained at a same time.

The disclosed method involves: recording, under illumination of a diffractive measurement structure via an illumination device, a plurality of diffraction images which differ from one another in terms of the region of the measurement structure that contributes to the respective diffraction image, and ascertaining transmission properties and/or reflection properties of the diffractive measurement structure based on the plurality of diffraction images, wherein the steps of recording a plurality of diffraction images and of ascertaining transmission properties and/or reflection properties of the diffractive measurement structure in a plurality of recording sequences are carried out repeatedly in a plurality of recording sequences, wherein these recording sequences differ from one another with respect to the illumination angles that are respectively set during the illumination of the diffractive measurement structure and at which the diffractive measurement structure is illuminated.

A measurement apparatus (10) for interferometrically determining a surface shape of a test object (14). A radiation source provides an input wave (42), a multiply-encoded diffractive optical element (60), which is configured to produce by diffraction from the input wave a test wave (66) that is directed at the test object and has a wavefront in the form of a free-form surface and at least one calibration wave (70), and a capture device (46). The calibration wave has a wavefront with a non-rotationally symmetric shape (68f), wherein cross sections through the wavefront of the calibration wave along cross-sectional surfaces each aligned transversely to one another have a curved shape. The curved shapes in the different cross-sectional surfaces differ in terms of an opening parameter. The capture device (46) captures a calibration interferogram formed by superimposing a reference wave (40) with the calibration wave after interaction with a calibration object (74).

An inspection device includes an objective lens that transmits inspection light reflected from a sample during inspection and measurement light from a point light source during aberration measurement, a first pupil relay lens that transmits the inspection light and the measurement light, a second pupil relay lens in which an intermediate imaging plane is formed between the second pupil relay lens and the first pupil relay lens, a diffraction grating disposed between the first pupil relay lens and the intermediate imaging plane and that diffracts the measurement light, a point diffraction interferometry plate disposed within a depth of focus of the intermediate imaging plane and that selectively transmits the diffracted light, a first detector that detects an image of the sample, and a second detector that detects a fringe image of the measurement light.

Methods, apparatus and systems for testing an optical element are described. One example device for measuring a test optical component includes a pre-conditioning optical module positioned to receive an optical beam from a light source and to produce a beam having a non-collimated beam profile or a freeform wavefront. The device further includes a beam splitter positioned to receive the beam output from the pre-conditioning optical module and to direct a first portion of the beam to a reference arm configured to accommodate a reference optical component, and to direct a second portion of the beam to a test arm configured to accommodate the test optical component. The device also includes a beam combiner positioned to receive the beams from the reference arm and the test arm after reflection or refraction by the reference and the test optical components.

System and methods are provided for characterizing an internal surface of a lens using interferometry measurements. Sphere-fitting a distorted radius determines distorted pathlengths. Ray-tracing simulates refraction at all upstream surfaces to determine a cumulative path length. A residual pathlength is scaled by the group-index and rays are propagated based on the phase-index. After aspheric surface fitting, a corrected radius is determined. To estimate a glass type for the lens, a thickness between focal planes of the lens surfaces is determined using RCM measurements. Then, for both surfaces, the surface is positioned into focus, interferometer path length matching is performed, a reference arm is translated to stationary phase point positions for three wavelengths to determine three per-color optical thicknesses, and ray-tracing is performed. A glass type is identified by minimizing an error function based on optical parameters of the lens and parameters determined from known glass types from a database.

A detection device adapted to detect lens surface and a stitching interferometer including the same are disclosed. The detection device includes: a cylindrical detection frame comprising support bosses arranged on an inner wall of the detection frame in a circumferential direction of the detection frame, the lens to be detected being placed on the support bosses; and a plurality of support units mounted at a bottom of the detection frame in the circumferential direction of the detection frame, each of the support units comprising: a support mechanism configured to be movable in an axial direction of the detection frame and cooperate with the support bosses so as to support the lens to be detected together; and a balance mechanism configured to provide a balancing force for balancing with force of the support mechanism for supporting the lens to be detected, so that axial support force of each supporting unit for the lens to be detected is equal to axial support force of each support boss for the lens to be detected in both cases where the axial direction of the detection frame is parallel to a gravity direction of the lens to be detected and inclined with respect to the gravity direction of the lens to be detected.

A method for high-accuracy wavefront measurement based on grating shearing interferometry, which adopts a grating shearing interferometer system comprising an illuminating system, an optical imaging system under test, an object plane diffraction grating plate, an image plane diffraction grating plate, a two-dimensional photoelectric sensor, and a calculation processing unit. The object plane diffraction grating plate and the image plane diffraction grating plate are respectively arranged on the object plane and the image plane of the optical imaging system under test. The shearing phase of 1.sup.st-order diffracted beam and −1.sup.st-order diffracted beam is exactly extracted through phase shifting method, and the original wavefront is obtained by carrying out reconstruction algorithm according to a shear ratio of 2s, such that the accuracy of wavefront measurement of the optical imaging system under test is improved, wherein s is the shear ratio of the grating shearing interferometer.

A method, device and electronic apparatus for estimating physical parameters are disclosed. The method includes: reading a Newton's rings fringe pattern obtained by performing an interferometric measurement on a unit to be measured; obtaining the number and length of first-direction signals of the Newton's rings fringe pattern; performing, for each of the first-direction signals, a discrete chirp Fourier transform (DCFT) on the first-direction signal based on each first chirp rate parameter within a range of the length of first-direction signals, to obtain a first magnitude spectrum of an intensity distribution signal in a DCFT domain; determining a first chirp rate parameter and a first frequency parameter corresponding to a first magnitude peak value based on the first magnitude spectrum; and estimating the physical parameters involved in the interferometric measurement at least according to the first chirp rate parameter and first frequency parameter corresponding to the first magnitude peak value. In this way, the physical parameters involved in the interferometric measurement can be estimated with high accuracy and stably.

Methods and apparatus to calibrate spatial light modulators are disclosed. Examples include processor circuitry to execute and/or instantiate instructions to provide a greyscale image to a spatial light modulator (SLM) to define voltages to be applied to individual pixels of the SLM. The voltages associated with pixel values in the greyscale image. The pixel values arranged in a double-slit grating pattern. The SLM to produce an interference pattern based on the double-slit grating pattern. The processor circuitry is to determine a phase difference between first and second gratings of the double-slit grating pattern based on the interference pattern. The processor circuitry is to generate a phase curvature based on the phase difference.