27 results about "Shearing interferometer" patented technology

The invention discloses a method for measuring a detection inclination angle of a two-component atomic shearing interferometer. The method comprises the following steps: constructing an inclination angle set of an angle swinging device; when the atoms are acted by the pi Raman laser and the second pi / 2 Raman laser, the reflecting mirror rotates by an angle; alternately detecting multiple groups of odd-numbered groups and even-numbered groups; traversing all dip angles in the dip angle set; and fitting and calculating the actual included angle of the longitudinal direction of the imaging surface of the CCD camera relative to the Z-axis direction. The invention further discloses a measuring device for the detection inclination angle of the two-component atom shearing interferometer. According to the method, an existing atom shearing interferometer can accurately measure the inclination angle of a detection system of the atom shearing interferometer, so that the problems of noise and system errors caused by the fact that the inclination angle of the detection system of the atom shearing interferometer does not return to zero are solved, and drifting of differential measurement of the two-component atom interferometer caused by inclination angle changes is restrained.

The utility model discloses a wavefront debugging and detecting device for a laser beam-expanding lens, which is used for debugging and detecting a laser beam-expanding lens to be detected and comprises a laser light source part, a standard laser beam-expanding lens, a pinhole diaphragm and a shearing interferometer which are sequentially arranged and are coaxial at equal height, and the laser beam-expanding lens to be detected is arranged between the pinhole diaphragm and the shearing interferometer. The laser light source part is used as a standard laser light source, the standard laser beam expanding lens is used for expanding the standard laser light source to an entrance pupil size matched with that of the laser beam expanding lens to be measured, and the small-hole diaphragm is used for limiting the spot diameter of the standard laser light source entering the laser beam expanding lens to be measured; and the shearing interferometer is used for testing the wavefront of the standard laser light source after passing through the to-be-tested laser beam expanding lens. According to the utility model, the laser light source piece, the standard lens and the shearing interferometer are utilized, the wavefront debugging precision is improved, and the wavefront aberration is reduced by observing interference fringes in real time and finely adjusting the lens and guiding lens installation and stress release, so that the problem that the beam expanding multiple is reduced is solved.

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.

A radial shearing interferometer based on a bifocal photonic sieve includes two identical bifocal photonic sieves, an image detector, and a computer. The focal points of the two bifocal photonic sieves correspond to each other, generating two 4f systems. This causes the incident wavefront to be measured to be split into two beams of different sizes, which undergo shearing interference on the image detector. The computer can extract the shearing phase difference from the interferogram received from the image detector, thus obtaining the phase information carried in the beam. This invention features a simple structure, low requirements for the experimental environment, and strong anti-interference capability, and can be applied to many fields such as wavefront detection, interferometric imaging, and adaptive optics.

In order to efficiently measure the aberration of an optical member, when measuring shear interference, it is possible to perform measurement of an interference wavefront, which has been performed a plurality of times in the past, by one measurement. In a shear interferometer that performs wave division of a light beam between a light source and a lens to be measured, and irradiates the divided light beam to the lens to be measured to cause interference, wave division is performed by a pinhole plate disposed between the light source and the lens to be measured, and three or more pinholes that are not on the same straight line are provided in the pinhole plate.

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 present invention discloses a bidirectionally coupled optical near-field alignment system based on an off-axis parabolic reflector, comprising a forward optical path, a reverse optical path, and a pair of coupled reflectors; the forward optical path comprises a light source module, an interferometer module, an OAP and an adjustment mechanism module, a probe, and a sample stage module; the reverse optical path, based on the forward optical path, switches the sample into a point light source, which emits laser light in the reverse direction. After being reflected by the OAP, the laser light is split into two paths by a newly added shearing interferometer. The bidirectionally coupled optical near-field alignment system based on an off-axis parabolic reflector disclosed by the present invention adopts a bidirectionally coupled optical near-field alignment method based on a standard OAP, which can reduce the difficulty of near-field coupling alignment and improve near-field coupling efficiency. It can also realize automated near-field coupling alignment based on quantitative and visual criteria, and has broad commercial prospects in large-scale and industrial applications.

The present invention proposes a radial shearing interferometer plate based on a metasurface structure, which relates to the field of optical detection technology. The radial shearing interferometer plate is composed of two metasurface optical lenses with different focal lengths integrated into one; the metasurface optical lens is based on a phase-controlled metasurface unit structure as a basic structural unit, and the phase-controlled metasurface unit structure is staggered into a concentric ring structure with a width less than or equal to λ / 2 according to two different phase control parameters. The two metasurface optical lenses occupy odd and even rings respectively to form the radial shearing interferometer plate. The present invention has the advantages of polarization independence, high energy utilization, simple structure, small size, high integration, high precision, high spatial resolution, high speed, not susceptible to environmental interference, no need for reference light setting, no leakage of wavefront information, easy adjustment of shear rate, and high dynamic range of detection, which can meet the requirements of real-time and accurate laser wavefront detection.

The invention discloses a bidirectional coupling optical near-field alignment system based on an off-axis parabolic mirror. The bidirectional coupling optical near-field alignment system comprises a forward light path, a reverse light path and a coupling mirror pair, the forward light path comprises a light source module, an interferometer module, an OAP and adjusting mechanism module and a probe and sample stage module; the reverse light path is used for switching a sample into a point light source on the basis of the forward light path, the point light source reversely emits laser, and the laser is divided into two paths by a newly added shearing interferometer after being reflected by the OAP. According to the two-way coupling optical near-field alignment system based on the off-axis parabolic mirror, the two-way coupling optical near-field alignment method based on the standard OAP is adopted, the near-field coupling alignment difficulty can be reduced, the near-field coupling efficiency can be improved, automatic near-field coupling alignment can be achieved according to quantitative and visual criteria, and the accuracy of the near-field coupling alignment is improved. And the method has a wide commercial prospect in large-scale and industrial applications and the like.

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 present invention discloses a shear rate calibration device and method for a transverse shearing interferometer. The device allows the calibration plate to be tilted at any angle in the direction perpendicular to the optical axis and is simple to operate. The device is also applicable when the incident light is a spherical wave with a certain known divergence or convergence angle. The method can make adjustments when there is a rotation error in the shear direction, and reduces the steps of image processing, thereby improving the accuracy and computational efficiency of shear rate measurement. The device includes a calibration platform, a plug-in fixture, a double-slit calibration plate, a grating, a CCD detector, and a computer. First, the calibration component, the double slit, is placed between the light source and the detection surface of the CCD. The double slit is fixed with a fixture and can move freely in the axial direction of the system. The position of the shear rate required by the grating measured using the double slit is recorded, and the axial movement of the fixture is restricted. The double slit is removed from the plug-in fixture and the grating is inserted to complete the calibration.

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.

Method for detecting wave aberration of high-precision projection objective by grating shearing interferometry. The grating shearing interferometer system adopted by this method includes: an optical and illumination system, an optical imaging system to be measured, a diffraction grating plate on the object plane, a diffraction grating plate on the image plane, a two-dimensional optoelectronic sensor, and a calculation and processing unit. The diffraction grating plate on the object plane and the diffraction grating plate on the image plane are respectively placed on the object plane and the image plane of the optical imaging system to be measured. During measurement, by means of axial scanning, the differential wavefronts at two or more positions in the axial direction are measured, and the Z2 coefficient of the differential wavefront in the x direction and the Z3 coefficient of the differential wavefront in the y direction at the axial position are obtained by fitting. The Z5 astigmatism error of the optical imaging system to be measured is directly obtained by linearly fitting the axial grating position using the Z2 and Z3 coefficients, eliminating the astigmatism error introduced by the grating defocus and position change in the shearing interferometer system. This method does not require the fabrication of additional gratings and does not require the additional addition of a turntable, which not only improves the wave aberration measurement accuracy of the optical imaging system to be measured but also does not increase the complexity of the measurement system structure.

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.

This invention provides a microscopic interferometric imaging spectroscopic device and its implementation method based on an external pushbroom. The observation target, located in the illumination field of view, is imaged by an infinity-conjugate microscope objective. Parallel light is then incident on a transverse shearing interferometer module. Two parallel light beams obtained from the transverse shearing interferometer module pass through a Fourier lens group within the imaging lens, generating interference fringes on a planar array camera. Based on a spatial interferometric microscopic imaging optical path with no moving parts, linear pushbroom microscopic imaging is achieved by displacing the sample via an electric stage, obtaining a continuous time-distributed sequence of interference images. The light intensity corresponding to the observation target in each image is extracted from the interference image sequence and recombined to form the interference information of the observation target. Then, a computing unit performs a Fourier transform on this interference information to invert the spectral information of the observation target. The internal components of the interferometer module of this device remain stationary, ensuring the long-term stability and reliability of the hyperspectral microscopic imaging device.

The invention discloses a method for measuring a detection inclination angle of a single-component atom shearing interferometer, which comprises the following steps of: constructing an inclination angle set of an angle swinging device; when the atoms are acted by the pi Raman laser and the second pi / 2 Raman laser, the reflecting mirror rotates by an angle; detecting the cut interference fringe image; traversing all dip angles in the dip angle set; and fitting and calculating the actual included angle of the longitudinal direction of the imaging surface of the CCD camera relative to the Z-axis direction. The invention further discloses a measuring device for the detection inclination angle of the single-component atom shearing interferometer. According to the method, an existing atom shearing interferometer can accurately measure the inclination angle of a detection system of the atom shearing interferometer, so that the problems of noise and system errors caused by the fact that the inclination angle of the detection system of the atom shearing interferometer does not return to zero are solved, and drifting of differential measurement of the single-component atom interferometer caused by inclination angle changes is restrained.

The invention discloses an ultrafast laser three-dimensional space-time wave packet single measurement method and device. The device comprises a beam splitting grating, an ultra-narrow band filter, a shearing interferometer, a spectrum phase measurer and a control and calculation device. A to-be-measured light beam is divided into replicated light beams in different propagation directions through the beam splitting grating, the ultra-narrow band filter enables the to-be-measured light beams at different angles to pass through different central wavelengths, the filtered light beams enter the shearing interferometer, and an interferogram is recorded by the detector. And wavefront information corresponding to each wavelength can be recovered by analyzing the interferograms. The method is simple and reliable in principle, strong in anti-interference capability, high in precision, high in space-time bandwidth product and fast in speed, and is especially suitable for on-line measurement of short pulse laser three-dimensional light field distribution.