CN-121977796-A - Optical system wavefront detection device and method based on phase modulation

CN121977796ACN 121977796 ACN121977796 ACN 121977796ACN-121977796-A

Abstract

The invention relates to an optical parameter detection device and method, in particular to an optical system wavefront detection device and method based on phase modulation. In order to solve the defects that a multi-frame acquisition strategy is difficult to be suitable for a dynamic test scene, a single-frame acquisition strategy is difficult to stably invert a wavefront with conjugate symmetry and the iterative inversion operation time is long and a local optimal solution is possibly involved in a phase recovery method based on a point spread function in the prior art, the invention provides an optical system wavefront detection device based on phase modulation. Based on the device, the method provided by the invention combines an unsupervised deep neural network with a physical driving layer to realize accurate inversion of different optical systems to be detected.

Inventors

HE YIFAN
XUE XUN
CHEN ZEYU
CHANG NING

Assignees

中国科学院西安光学精密机械研究所

Dates

Publication Date: 20260505
Application Date: 20251231

Claims (10)

1. An optical system wavefront detection device based on phase modulation, which is characterized in that: The device comprises a light source module, a first imaging lens (3), a first plane reflecting mirror (4) and a beam splitter (5) which are sequentially arranged along the output end of the light source module, a microscope objective (6) and a second plane reflecting mirror (8) which are sequentially arranged along the reflecting light path of the beam splitter (5), and a partitioned phase plate (9), a second imaging lens (10) and a photoelectric detector (11), wherein an optical system (7) to be tested is arranged between the microscope objective (6) and the second plane reflecting mirror (8); The first imaging lens (3) is used for converting light emitted by the light source module into parallel light, the parallel light sequentially passes through the first plane mirror (4) and the beam splitter (5) and then sequentially passes through the microobjective (6) and the optical system to be detected (7) to the second plane mirror (8), and then the parallel light is reflected by the second plane mirror (8) and returns to the original path to form light carrying wavefront information of the optical system to be detected (7) and is transmitted to the beam splitter (5), the zonal phase plate (9), the second imaging lens (10) and the photoelectric detector (11) are sequentially arranged on a light path of the light carrying the wavefront information after being transmitted by the beam splitter (5), and the light carrying the wavefront information sequentially passes through the zonal phase plate (9) and the second imaging lens (10) and reaches the photoelectric detector (11); The optical system comprises a light source module, a photoelectric detector (11), a microscope objective (6), a second imaging lens (10) and a light source module, wherein the light source module is used for providing a point light source for geometric imaging and diffraction imaging, and an output end is conjugated with an image surface of the photoelectric detector and a focal surface of the microscope objective (6) respectively; the zoned phase plate (9) is used for carrying out phase modulation on the pupil of the optical system (7) to be tested to realize asymmetric phase coding, and the total phase after the optical system (7) to be tested and the modulation phase are linearly overlapped meets the following conditions , wherein, Is the space coordinate of the pupil plane The total phase after superposition; The second imaging lens (10) is used for converging parallel light to an image plane of the photodetector (11); the photodetector (11) is used for acquiring PSF intensity distribution, generating a PSF intensity image, and calculating the wavefront aberration of the optical system.
2. The phase modulation-based optical system wavefront sensing device of claim 1, further comprising: the phase distribution of the zoned phase plate (9) satisfies non-rotational symmetry, i.e , wherein, Is the space coordinate of the pupil plane Phase distribution at that point.
3. The phase modulation-based optical system wavefront sensing device of claim 2, further comprising: The light source module comprises a light source (1) and a pinhole assembly (2) arranged at an outlet of the light source (1), wherein the pinhole assembly (2) is used for forming a point light source through spatial filtering; the pinhole component (2) is positioned at the focal plane of the first imaging lens (3) and is conjugate with the image plane of the photodetector (11).
4.A phase modulation based optical system wavefront sensing device as defined in claim 3, wherein: The pinhole component (2) comprises a plurality of small holes with different diameters, and the small holes with different diameters are used for changing to realize geometric imaging and diffraction imaging of the point light source; The micro objective lens (6) comprises different numerical apertures and magnifications so as to match the wavefront detection of different optical systems (7) to be detected, and the numerical aperture of the micro objective lens (6) is larger than the numerical aperture of the optical system (7) to be detected.
5. A phase modulation based optical system wavefront sensing device according to any one of claims 1-4, wherein: The system further comprises a calculation unit (12) connected with the photoelectric detector (11), wherein the calculation unit (12) is used for obtaining wavefront aberration of the optical system to be detected based on PSF intensity image inversion; The beam splitter (5) is a non-polarizing beam splitter; The size of the second plane reflecting mirror (8) is larger than the caliber of the optical system to be detected so as to ensure the integrity of the acquired PSF intensity image; the zoned phase plate (9) adopts a four-zone phase plate, and the additional phases of each quadrant are respectively 0, pi/4, pi/2 and 3 pi/4; The photoelectric detector (11) is a CCD, and the dynamic range is more than 12 bits.
6. The wavefront detection method of the optical system based on phase modulation is characterized by comprising the following steps of: Step 1, constructing the phase modulation-based optical system wavefront detection device according to any one of claims 1-5; step 2, calibrating the device, namely calibrating inherent aberration of the device ; Step 3, adjusting the device, namely adjusting the light source module to perform geometric imaging, setting and adjusting the position of the optical system (7) to be measured, so that the focal plane of the optical system to be measured is overlapped with the focal plane of the microscope objective, and the optical axis of the optical system to be measured is overlapped with the optical axis of the microscope objective; Step 4, image preprocessing, namely adjusting a light source module to carry out diffraction imaging, and acquiring an original PSF intensity image by a photoelectric detector (11) Preprocessing to obtain an image to be inverted , wherein, Is the space coordinates of the image plane; step 5, wavefront inversion of the optical system to be tested according to the theoretical PSF intensity distribution of the optical system to be tested (7) Mapping relation between the optical system wave front aberration to be measured and the optical system wave front aberration to be measured by minimizing theoretical PSF intensity distribution And the image to be inverted And performing wavefront inversion according to the consistency, and calculating the wavefront aberration of the optical system to be measured.
7. The method for wavefront detection of an optical system based on phase modulation as claimed in claim 6, wherein in step 5, the theoretical PSF intensity distribution of said optical system (7) to be detected is determined The mapping relation between the wavefront aberration and the wavefront aberration of the optical system to be measured is specifically: ; Wherein, the Representing the fourier transform of the signal, For the spatial coordinates of the optical system (7) to be measured in the pupil plane The amplitude of the pupil plane at which, Is the space coordinate of the pupil plane The wavefront aberration of the optical system to be measured, Is the space coordinate of the pupil plane The device-specific aberration, i, is a complex unit.
8. The phase modulation-based optical system wavefront sensing method of claim 7, wherein in step 5, the passing minimizes a theoretical PSF intensity distribution And the image to be inverted The consistency between the two is used for carrying out wavefront inversion, and the wavefront aberration of the optical system to be measured is calculated, specifically: The image to be inverted Inputting a deep neural network, calculating and outputting a Zernike polynomial coefficient alpha of an optical system (7) to be measured by using the deep neural network, and enabling the Zernike polynomial coefficient alpha and wavefront aberration of the optical system to be measured The following relationship exists: ; Wherein, the For a Zernike polynomial, i.e. a set of orthogonal functions defined on a unit circle, The j-th Zernike polynomial coefficient is obtained, M is the Zernike polynomial fitting term number; The Zernike polynomial coefficient alpha and the inherent aberration of the device Together input to the physical driving layer Generating a theoretical PSF intensity distribution based on the mapping relationship ; ; Construction of a loss function Using deep neural network to pair loss function Carrying out minimized solution on iteration until convergence conditions are met, stopping iteration, and outputting current theoretical PSF intensity distribution Corresponding wavefront aberration of optical system to be measured 。
9. The phase modulation-based optical system wavefront detection method of claim 8, further comprising: In step 2, the method further comprises obtaining a dark current image Flat field image ; In step 4, the preprocessing is specifically to use dark current image Peace field image For the acquired original PSF intensity image Performing dark field removal, flat field correction and stretching treatment, and stretching by adopting logarithmic transformation to obtain an image to be inverted ; In step 5, the loss function The method comprises the following steps: ; Wherein, the In order to learn the network in a deep manner, As a result of the weight of the network, For the two-norm operator, In the case of a structural similarity index operator, Is an adjustable super parameter.
10. The phase modulation-based optical system wavefront detection method of claim 6, further comprising: The step 2 comprises setting standard lens with known wavefront aberration between the microscope objective (6) and the second plane mirror (8), measuring current device observed wavefront with interferometer under the same condition as the test, and subtracting the measured device observed wavefront from the known wavefront of standard reference lens to obtain device inherent aberration ; The step 3 is that the optical system (7) to be measured is placed according to the theoretical reference focus position of the optical system (7) to be measured, the light source module is adjusted to perform geometric imaging, the relative position of the optical system (7) to be measured and the microscope objective (6) is adjusted in the vicinity of the theoretical reference focus position, the point source image of the photoelectric detector (11) is observed, and when the point source light source is in an ideal circular shape and the size is minimum in the image plane, the focal plane of the microscope objective and the focal plane of the optical system to be measured, and the optical axis of the microscope objective and the optical axis of the optical system to be measured are all determined to be coincident.

Description

Optical system wavefront detection device and method based on phase modulation Technical Field The invention relates to an optical parameter detection device and method, in particular to an optical system wavefront detection device and method based on phase modulation. Background Wavefront detection is a fundamental link in optical manufacturing, assembly and system calibration, in which a wavefront detection result is generally used as a criterion for quality of an optical system, and the system is guided to manufacture, assemble and calibrate until the detection result meets the design accuracy requirement. Wavefront sensing methods include interferometry (e.g., michelson, mach-Zehnder interferometers), wavefront sensing (e.g., shack-Harmann wavefront sensors), and phase recovery based on point spread functions. Interferometry, while highly accurate, is sensitive to the environment (vibration, air turbulence, beam collimation), and the system is complex, with high engineering deployment costs. The wavefront sensing method can directly measure, has real-time performance, generally requires a complex sampling device, has limited spatial resolution and wavefront detection precision, and has the advantages of simple detection device, good environmental stability and better spatial resolution capability. The phase recovery method based on the point spread function generally adopts two strategies of multi-frame acquisition and single-frame acquisition. The multi-frame acquisition realizes wavefront inversion by acquiring PSF images of a focal plane and a defocusing position, which is beneficial to improving inversion precision, but in order to acquire multi-frame PSF images, additional moving parts are generally required to be introduced for multiple acquisitions, so that time resolution is reduced, mechanical complexity is increased, and the multi-frame PSF images are difficult to be suitable for dynamic test scenes. The real-time performance of single frame acquisition is stronger, but the acquired information is limited, and the wavefront detection precision is seriously dependent on the uniqueness of the solution and the convergence of the algorithm. However, the wavefront with conjugate symmetry can generate the same intensity distribution, which directly damages the uniqueness of the phase recovery solution and limits the application of a single frame acquisition strategy, on the other hand, the existing phase recovery algorithm inverts the wavefront through iteration, the operation time is long, and the difference of iteration initial value selection can cause the inversion wavefront to fall into a local optimal solution. Disclosure of Invention The invention aims to solve the defects that a multi-frame acquisition strategy is difficult to be suitable for a dynamic test scene by adopting a phase recovery method based on a point spread function, a single-frame acquisition strategy is difficult to stably invert a wavefront with conjugate symmetry, iteration inversion operation time is long and a local optimal solution is possibly involved in the prior art, and provides an optical system wavefront detection device and method based on phase modulation. Firstly, introducing asymmetric phase codes into a detection device to effectively destroy conjugate symmetric wavefront distribution of an optical system to be detected, thereby destroying symmetry causing multiple solutions and enabling observed intensity information to be more sensitive to wavefront change and more distinguishable. Secondly, the development of the deep learning technology provides new possibility for a phase recovery method, and the mapping relation between the wavefront aberration and PSF intensity distribution is established through training, so that the wavefront aberration can be inverted more quickly and accurately. In order to achieve the above purpose, the technical solution provided by the present invention is as follows: The optical system wavefront detection device based on phase modulation is characterized by comprising a light source module, a first imaging lens, a first plane reflecting mirror, a beam splitter, a microscope objective, a second plane reflecting mirror, a zoned phase plate, a second imaging lens and a photoelectric detector, wherein the first imaging lens, the first plane reflecting mirror and the beam splitter are sequentially arranged along the output end of the light source module; the optical system to be measured is arranged between the microscope objective and the second plane reflecting mirror; the first imaging lens is used for converting light emitted by the light source module into parallel light, the parallel light sequentially passes through the first plane mirror and the beam splitter and then sequentially passes through the microobjective and the optical system to be tested to the second plane mirror, and then is reflected by the second plane mirror and returned to form light carrying wavefront info