15 results about "Shearing interferometer" patented technology

The application discloses a method for measuring a detection tilt angle of a two-component atomic shearing interferometer, constructs a tilt angle set of a swing angle device; the angle of a mirror is turned between the time when atoms are subjected to the action of a pi Raman laser and a second pi / 2 Raman laser; a plurality of groups of odd number and even number are alternately detected; all tilt angles in the tilt angle set are traversed; and the actual included angle of the longitudinal direction of a CCD camera imaging surface relative to the Z-axis direction is calculated by fitting. The application also discloses a measuring device for the detection tilt angle of the two-component atomic shearing interferometer. The application enables the current atomic shearing interferometer to accurately measure the tilt angle of the detection system, thereby solving the problems of noise and system error caused by the non-zero return of the tilt angle of the detection system of the atomic shearing interferometer, and suppressing the drift of the differential measurement of the two-component atomic interferometer caused by the change of the tilt angle.

The scheme belongs to the technical field of optical measurement, and discloses a device for quickly measuring the angle of a light beam, which comprises a shearing interferometer and an angle measuring tool. The shearing interferometer comprises a shearing plate and an observation plate marked with a reference line, the included angle between the shearing plate and the observation plate is 45 degrees, the extension planes of the surfaces of the shearing plate and the observation plate facing or away from each other intersect, and the intersection line is perpendicular to the reference line. The shearing plate is used for shearing a to-be-measured parallel light beam into a first light beam and a second light beam and reflecting them to the observation plate, the observation plate is used for observing the interference fringes of the first light beam and the second light beam, and the angle measuring tool is used for measuring the rotation angle of the shearing interferometer rotating around the normal line of the observation plate from an initial posture to an end posture. The initial posture refers to the posture of the shearing interferometer when the reference line is parallel to the projection of the reference line of the to-be-measured parallel light beam on the observation plate, and the end posture refers to the posture of the shearing interferometer when the interference fringes are parallel to the reference line.

This invention discloses a method and apparatus for obtaining the original aperture and shearing amount of an interference system with arbitrary aperture. The method includes: acquiring multiple frames of phase-shifted interferograms in the x and y directions of a transverse shearing interferometer system, and fusing them to obtain a spatial modulation quality map; using the gray values ​​of each pixel in the spatial modulation quality map as features, and employing a K-means clustering algorithm to label each pixel as an interference region, a non-interference region, and a background region; based on the known shearing direction, spatially reorganizing the interference region and the non-interference region to generate an original aperture mask and a sheared aperture mask; calculating the centroid coordinates of the mask, and determining the shearing amount based on the distance between the two centroids. This invention requires no prior knowledge of the aperture shape, is fully automated, and is applicable to arbitrary apertures such as rectangles, ellipses, and rings. It also maintains high robustness and accuracy in interferograms with dense fringes, blurred edges, or noise.

A system may include a lateral shearing interferometer. The lateral shearing interferometer may enable measuring a surface profile of a sample, such as the pattern wafers, using reflected light from the sample. The reflected light may be reflected at a grazing incidence angle. A controller may receive images from the lateral shearing interferometer and measure the surface profile. The controller may measure the surface profile by reconstructing a phase of the reflected light from the images. The controller may reconstruct the phase using spatial reconstruction or time-domain reconstruction. The gratings may allow the controller to measure the edge roll-off in one or two dimensions. The controller may also calibrate the grazing incidence angle and determine refractive indices of thin-films on the sample. The controller may also perform full measurements of the surface profile using line beams, rectangular beams, or full-sample beams.

The application discloses a four-wave transverse shearing interferogram effective area segmentation system and method based on FFT and global threshold, and belongs to the technical field of optical interference measurement and wavefront sensing. The method comprises an image acquisition module, a preprocessing module, an FFT low-frequency extraction module, an automatic threshold segmentation module and a morphological optimization module. The application carries out smooth processing on the background brightness distribution of the interferogram through FFT low-pass filtering, and realizes automatic segmentation of the effective area in combination with Otsu global threshold, effectively avoids technical defects such as center area inversion blackening, edge fracture and excessive noise that are prone to occur in traditional area segmentation methods, can completely extract the four-wave overlapping area, has the advantages of stable segmentation, strong anti-interference capability, no need for manual parameter adjustment, good real-time performance and the like, and can be widely applied to various four-wave transverse shearing interferometer wavefront detection systems.

The application discloses a wave front measurement method and device based on a double-frequency grating, and belongs to the technical field of optical detection and precision measurement. The method integrates two improved Hartmann mask plates with different periods on the same substrate to construct a double-frequency grating. When measuring the same to-be-measured wave front, the large dynamic range characteristic of the low-frequency grating is utilized to realize non-ambiguity unwrapping of high-frequency phase information, so that the dynamic range of the system is significantly improved on the premise of completely reserving the original spatial resolution of the high-frequency grating. The core advantage of the application is that the large gradient measurement capability and high spatial resolution accuracy can be achieved through single acquisition, and the problem that the dynamic range and resolution are restricted by each other in the traditional four-wave lateral shearing interferometer is effectively solved, so that an innovative and efficient solution is provided for high-precision complex surface shape detection.

The invention discloses a double-grating Ronchi shear interference variable shear rate differential wavefront reconstruction method based on deep learning, and the method comprises the steps: inputting initial data, which comprises an idealized differential wavefront signal, a differential wavefront signal with a shear error, and a corresponding ideal wavefront Zernike coefficient to be measured; labeling the initial data in a preset error rate interval, and forming a data set by the wavefront Zernike coefficient, the differential wavefront signal and a corresponding label; constructing an initial model which comprises a multi-path feature extraction module, a feature fusion module and a prediction module; training the initial model by using the data set to obtain a prediction model; and inputting the differential wavefront signal into the prediction model to predict a differential Zernike coefficient matrix, and calculating a wavefront Zernike coefficient to be measured for wavefront reconstruction based on the differential Zernike coefficient matrix obtained by prediction. The method provided by the invention can effectively improve the robustness of the double-grating Ronchi shear interference system.

The invention relates to a wavefront measurement system and method for improving spatial resolution by using a Hartmann system of an interferometer, and belongs to the field of optical precision detection, a point light source forms wavefront with aberration through atmospheric turbulence, the wavefront is transmitted to a collimating lens, parallel light beams are emitted, the parallel light is split through a spectroscope, and one path enters a radial shearing interferometer; and the other path sequentially enters a 4f low-pass filtering system and then enters a Hartmann wavefront sensor, and finally wavefront information acquired by the Hartmann wavefront sensor and the radial shearing interferometer is transmitted to a wavefront signal processing computer for wavefront reconstruction. The invention relates to a joint detection method of a shearing interferometer and a Hartmann wavefront sensor, which comprises the following steps of: transmitting low-order aberration detected by the Hartmann wavefront sensor to the interferometer, analyzing an interference image of the interferometer, iterating intermediate-frequency aberration and high-frequency aberration on the basis of the low-order aberration detected by the Hartmann wavefront sensor, and finally detecting the low-order aberration by the Hartmann wavefront sensor. Therefore, the spatial resolution and absolute precision of wavefront measurement are improved.

The present disclosure provides a measurement system (shear interferometer) for determining an aberration map of a projection system (e.g., within a lithographic apparatus). The measurement system comprises: a first patterned device positionable in an object plane of the projection system; a second patterned device positionable in an image plane of the projection system; and a radiation detector arranged to receive radiation from the second patterned device. The second patterned device has a variable pitch such that an angular spacing between adjacent pairs of diffracted beams formed by the second patterned device is non-uniform. The pitch of the second patterned device may have an extremum at a first location on the second patterned device, and the pitch of the second patterned device may increase or decrease with a distance from the first location.

The application discloses a method for measuring a detection tilt angle of a single-component atomic shearing interferometer, a method for measuring a detection tilt angle of a single-component atomic shearing interferometer, and a tilt angle set of a pendulum angle device is constructed; a rotation angle of a mirror is detected between the time when an atom is subjected to the action of a pi Raman laser and the time when the atom is subjected to the action of a second pi / 2 Raman laser; a shearing interference fringe image is detected; all tilt angles in the tilt angle set are traversed; and an actual included angle of a longitudinal direction of a CCD camera imaging plane relative to a Z-axis direction is calculated by fitting. The application further discloses a measuring device for a detection tilt angle of a single-component atomic shearing interferometer. The application enables the current atomic shearing interferometer to realize accurate measurement of a tilt angle of a detection system thereof, thereby solving the problems of noise and system error caused by the non-zero return of the tilt angle of the detection system of the atomic shearing interferometer, and suppressing the drift of the single-component atomic interferometer caused by the change of the tilt angle.

This invention discloses a wavefront reconstruction method, apparatus, computer equipment, and storage medium, relating to the field of optical measurement technology. The method includes: acquiring phase-shifted interferograms of two orthogonal shearing directions obtained by a transverse shearing interferometer system; performing wavefront reconstruction using a mode method based on the phase-shifted interferograms to obtain an initial reconstructed wavefront; determining the theoretical gradient field of the initial reconstructed wavefront and subtracting the theoretical gradient field from the original measured gradient field obtained during wavefront reconstruction using the mode method to obtain a target residual gradient field; constructing a gradient consistency constraint equation based on the target residual gradient field using the relationship between gradient and phase; solving the gradient consistency constraint equation and determining the target residual wavefront based on the solved residual wavefront; and superimposing the initial reconstructed wavefront and the target residual wavefront to obtain the target reconstructed wavefront. The solution of this invention ensures both global stability and noise resistance in wavefront reconstruction, as well as high-frequency detail recovery capabilities.

The invention provides a parameter determination system and method for a laser collimating mirror, and relates to the field of laser collimating mirrors. The system comprises a zoom adjustment module and a focal length determination module, wherein the zoom adjustment module comprises a fiber laser, a zoom lens, a shearing interferometer, a CCD camera and a spectroscope; the zoom lens and the spectroscope are sequentially arranged on an emergent light path of the optical fiber laser, and the spectroscope partially transmits and partially reflects so as to split emergent light of the zoom lens into first split light and second split light; the first split light enters the shearing interferometer; the second split light enters the CCD camera; the focal length determination module is used for measuring the focal length of the adjusted zoom lens. According to the system, aiming at lasers with different core diameters or powers, high-precision control of the sizes of collimated light spots is realized; in addition, the system is also convenient for manufacturing a prime lens with relatively small allowance in a later period, and light weight and miniaturization of the system are ensured.

This invention discloses a method for eliminating diffraction calculation errors in a checkerboard grating in a transverse shearing interferometer. The optical system of the transverse shearing interferometer includes: fixing the optical system under test on the optical platform of the transverse shearing interferometer; emitting incoherent light through an optical illumination system; the light rays sequentially passing through an object grating, the optical system under test, and an image grating, and being received by an optical detection element; uniformly shifting the phase of the object grating or the image grating to obtain shearing interference patterns in two perpendicular directions; using the least squares method to separate and solve for the shearing phases of the 0th and +1st order or 0th and -1st order diffracted light in the two perpendicular directions, and reconstructing the wavefront. This invention takes into account the different intensity coefficients of each diffraction order, accurately solves for the shearing phase, eliminates the errors introduced by the checkerboard grating in the whole-path diffraction calculation, and improves the wavefront reconstruction accuracy.

A system may include a lateral shearing interferometer. The lateral shearing interferometer may enable measuring a surface profile of a sample, such as the pattern wafers, using reflected light from the sample. The reflected light may be reflected at a grazing incidence angle. A controller may receive images from the lateral shearing interferometer and measure the surface profile. The controller may measure the surface profile by reconstructing a phase of the reflected light from the images. The controller may reconstruct the phase using spatial reconstruction or time-domain reconstruction. The gratings may allow the controller to measure the edge roll-off in one or two dimensions. The controller may also calibrate the grazing incidence angle and determine refractive indices of thin-films on the sample. The controller may also perform full measurements of the surface profile using line beams, rectangular beams, or full-sample beams.

The application discloses a kind of double-beam light spot positioning shear speckle interferometry automatic calibration methods, comprising: using double-beam laser calibrator to emit two parallel laser irradiation measuring plate, imaging by shear speckle interferometry system, obtain four containing two groups of parallel distribution ellipse interference spot images;The collected image is preprocessed to extract the light spot area;Ellipse profile is extracted using edge detection algorithm;Two-pass scanning method is used to judge the overlapping state of light spot;Non-overlapping light spot is directly based on least square ellipse fitting algorithm to obtain center coordinates;Overlapping light spot is first segmented into independent area by concave point matching, and then ellipse fitting is carried out;Four light spot center coordinates, laser center distance are substituted into Zhang calibration algorithm, and shear amount, shear direction and size conversion coefficient are calculated.The present application realizes full-process automatic non-contact calibration, has high precision and strong robustness, is suitable for various scenes, has high calibration efficiency, low cost and wide engineering applicability.