A Large Field-of-View 3D Phase Reconstruction System and Method Based on Coherent Modulation Imaging

Abstract

This invention discloses a large field-of-view three-dimensional phase reconstruction system and method based on coherent modulation imaging, belonging to the field of coherent modulation imaging. By translating the three-dimensional sample under test and acquiring diffraction patterns at different scanning positions, the imaging range is increased. A layered slicing method is used for phase reconstruction of the three-dimensional sample under test, enabling this method to reconstruct not only two-dimensional non-extended samples but also the complex amplitude distribution of three-dimensional extended samples ranging from tens to hundreds of micrometers. Furthermore, during reconstruction, the sample function and modulator function are updated simultaneously. An iterative projection algorithm is used to simultaneously reconstruct the complex field of the three-dimensional sample under test and the transmittance function of the modulator even with completely unknown modulator distribution. This allows for independent use without relying on other imaging methods, making coherent modulation imaging technology more independent and with a wider range of applications.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coherent modulation imaging, in particular to a large field of view three-dimensional phase reconstruction system and method based on coherent modulation imaging. BACKGROUND

[0002] With the urgent demand for high-resolution imaging, the light source in the field of short wavelength such as X-ray, deep ultraviolet and electron beam is applied more and more widely, and the optical imaging device used in this waveband is difficult to manufacture and has high cost, so the coherent diffraction imaging technology which does not depend on high-quality optical imaging elements plays a crucial role. Coherent modulation imaging is a new coherent diffraction imaging method, which has the advantages of simple imaging light path, short data acquisition time, etc., and is currently mainly applied to dynamic imaging, wavefront online diagnosis of high-power laser and detection of optical elements. Compared with the traditional coherent diffraction imaging method, the coherent modulation imaging technology introduces a phase modulator in the imaging light path, which plays a scattering role on the object light wave, thereby reducing the intensity of the central bright spot and reducing the requirement for the dynamic range of the detector. At the same time, due to the introduction of the modulator, the information of an object point can be distributed to many pixel points of the detector, which reduces the sensitivity to the noise of the detector in the reconstruction process, thereby significantly improving the convergence and robustness of the iterative method.

[0003] The traditional coherent modulation imaging technology needs to take the transmittance function of the modulator as prior information, which is generally calibrated in advance by the method of lamination imaging. Such a method makes the coherent modulation imaging technology have to rely on other imaging methods, and the imaging system is usually complex, and the signal-to-noise ratio of the imaging result is low. In addition, the current research on the coherent modulation imaging technology is mainly for two-dimensional samples and non-extensive samples, and the research on three-dimensional samples and extensive samples is less, and most samples have a certain thickness, so the measurement of three-dimensional objects is more general, and therefore a new method needs to be developed to make the coherent modulation imaging technology become a more independent and more widely applicable diffraction imaging technology. SUMMARY

[0004] The purpose of the present application is to provide a large field of view three-dimensional phase reconstruction system and method based on coherent modulation imaging, which can realize the phase reconstruction of three-dimensional samples and make the coherent modulation imaging technology more independent and more widely applicable.

[0005] To achieve the above purpose, the present application provides the following scheme:

[0006] A large field of view three-dimensional phase reconstruction system based on coherent modulation imaging, comprising: a semiconductor laser source, a spatial filtering collimation system, a beam splitter, a probe, a two-dimensional translation stage, a phase modulator, a detector and a computer.

[0007] The three-dimensional sample to be tested is placed on a two-dimensional translation stage, which is used to move the three-dimensional sample to be tested in two dimensions.

[0008] After each translation of the three-dimensional sample under test by the two-dimensional translation stage: the laser beam emitted by the semiconductor laser source passes through the spatial filtering and collimation system to output a plane wave; the plane wave is reflected by the beam splitter to form an incident light wave, which passes sequentially through the probe and the three-dimensional sample under test, and the outgoing wave of the three-dimensional sample under test reaches the phase modulator; the phase modulator applies phase modulation to the outgoing wave and transmits it to the detector, where the diffraction pattern of the scanning position of the three-dimensional sample under test is recorded; the scanning position is the position on the three-dimensional sample under test where the incident light wave is irradiated.

[0009] The detector is connected to a computer, which is used to acquire the diffraction patterns of the three-dimensional sample under test at different scanning positions recorded by the detector after multiple translations of the sample under test, and to reconstruct the phase of the three-dimensional sample under test using a multi-layer slicing method.

[0010] A large field-of-view three-dimensional phase reconstruction method based on coherent modulation imaging, wherein the method applies the aforementioned large field-of-view three-dimensional phase reconstruction system based on coherent modulation imaging, and the method includes:

[0011] Determine the diffraction propagation distance of the large field-of-view three-dimensional phase reconstruction system;

[0012] Obtain diffraction patterns at different positions of the three-dimensional sample to be tested, and determine the scanning position of the three-dimensional sample to be tested from each diffraction pattern;

[0013] The three-dimensional sample to be tested is divided into layers using a multi-layer slicing method.

[0014] Initialize the probe complex amplitude distribution, the complex amplitude distribution of each layer of the three-dimensional sample to be tested, and the transmittance function of the phase modulator;

[0015] Based on the scanning position determined for each diffraction pattern, the diffraction propagation distance, the initialized probe complex amplitude distribution, the initialized complex amplitude distribution of each layer of the three-dimensional sample under test, and the initialized transmittance function of the phase modulator, an iterative projection algorithm is used for each diffraction pattern to reconstruct the complex field of each layer of the three-dimensional sample under test at the scanning position and the transmittance function of the modulator.

[0016] Based on the complex field of each layer of the three-dimensional sample under test at the scanning position, the phase of each layer of the three-dimensional sample under test is obtained, thus forming the three-dimensional phase of the three-dimensional sample under test.

[0017] Optionally, determining the diffraction propagation distance of the large field-of-view three-dimensional phase reconstruction system specifically includes:

[0018] The diffraction propagation distance of the large field-of-view three-dimensional phase reconstruction system is determined from multiple diffraction pattern samples using an autofocus and position registration algorithm. The diffraction propagation distance includes the interlayer spacing of the three-dimensional sample, the diffraction propagation distance between the three-dimensional sample and the phase modulator, and the diffraction propagation distance between the phase modulator and the detector.

[0019] Optionally, the step of using an iterative projection algorithm to reconstruct the complex field of each layer of the three-dimensional sample at the scanning position and the transmittance function of the modulator based on the scanning position determined by each diffraction pattern, the diffraction propagation distance, the initialized probe complex amplitude distribution, the initialized complex amplitude distribution of each layer of the three-dimensional sample under test, and the initialized transmittance function of the phase modulator, specifically includes:

[0020] Based on the diffraction pattern, the scanning position determined by the diffraction pattern, the diffraction propagation distance, the initialized probe complex amplitude distribution, the initialized complex amplitude distribution of each layer of the three-dimensional sample under test, and the initialized transmittance function of the phase modulator, the exit field of each layer of the three-dimensional sample under test, the incident field of the phase modulator, the exit field of the phase modulator, and the planar light field of the detector are determined sequentially according to the propagation direction of the light wave.

[0021] The planar optical field of the detector is backpropagated to update the planar optical field of the detector, the output field of the phase modulator, the incident field of the phase modulator, and the output field of each layer of the three-dimensional sample under test in sequence.

[0022] Update the initial transmittance function based on the incident field of the updated phase modulator;

[0023] Based on the emission fields of each layer of the three-dimensional sample under test before and after the update, update the initialized probe complex amplitude distribution and the initialized complex amplitude distribution of each layer of the three-dimensional sample under test, and complete one iteration;

[0024] The next iteration is performed based on the updated probe complex amplitude distribution, the updated complex amplitude distribution of each layer of the three-dimensional sample to be tested, and the updated transmittance function, until the maximum number of iterations is reached or convergence is achieved, at which point the process ends.

[0025] Optionally, the emission field of each layer of the three-dimensional sample under test, the incident field of the phase modulator, the emission field of the phase modulator, and the planar light field of the detector, which are determined sequentially according to the propagation direction of the light wave, are as follows:

[0026] Emission fields of each layer of the three-dimensional sample under test: In the formula, This represents the emission field of the light wave after passing through the Nth layer, where n represents the nth scanning position of the three-dimensional sample under test, j represents the jth iteration, and the symbol · indicates element-wise multiplication. Let z0 represent the wave propagation operator, z0 represent the interlayer spacing of the three-dimensional sample, P represent the probe complex amplitude distribution, and O represent the wave propagation operator. N This represents the complex amplitude distribution of the Nth layer of the three-dimensional sample under test;

[0027] Incident field of phase modulator: In the formula, z1 represents the incident field of the phase modulator, and z1 represents the diffraction propagation distance between the three-dimensional sample and the phase modulator.

[0028] The output field of the phase modulator: In the formula, Let M represent the output field of the phase modulator, and M represent the transmittance function of the phase modulator.

[0029] The planar light field of the detector: In the formula, z1 represents the planar optical field of the detector, and z2 represents the diffraction propagation distance between the phase modulator and the detector.

[0030] Optionally, the updated planar light field of the detector is: In the formula, I represents the planar optical field of the updated detector. n This represents the diffraction pattern acquired at the nth scanning position of the three-dimensional sample under test;

[0031] The updated output field of the phase modulator is: In the formula, This represents the output field of the updated phase modulator. Represents the reverse wave propagation operator;

[0032] The incident field of the updated phase modulator is: In the formula, denoted by , where represents the incident field of the updated phase modulator, * denotes the complex conjugate operation, and α denotes the first feedback coefficient;

[0033] The updated emission fields of each layer of the three-dimensional sample under test are as follows: In the formula, This represents the emission field of the Nth layer of the updated three-dimensional sample under test.

[0034] Optionally, the transmittance function update formula for the phase modulator is:

[0035]

[0036] In the formula, Let represent the updated transmittance function, and β represent the second feedback coefficient.

[0037] Optionally, the update formula for the complex amplitude distribution of each layer of the three-dimensional sample to be tested is: In the formula, This represents the complex amplitude distribution of the Nth layer of the three-dimensional sample under test;

[0038] The update formula for the probe complex amplitude distribution is: In the formula, This represents the updated probe complex amplitude distribution corresponding to the Nth layer of the three-dimensional sample under test.

[0039] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0040] This invention discloses a large field-of-view three-dimensional phase reconstruction system and method based on coherent modulation imaging. By translating the three-dimensional sample under test and acquiring diffraction patterns at different scanning positions, the imaging range is increased. A layered slicing method is used for phase reconstruction of the three-dimensional sample under test. This method enables not only the reconstruction of two-dimensional non-extended samples but also the reconstruction of the complex amplitude distribution of three-dimensional extended samples ranging from tens to hundreds of micrometers. Furthermore, during reconstruction, the sample function and modulator function are updated simultaneously. An iterative projection algorithm is used to simultaneously reconstruct the complex field of the three-dimensional sample under test and the transmittance function of the modulator even with completely unknown modulator distribution. This method can be used independently without relying on other imaging methods, making coherent modulation imaging technology more independent and with a wider range of applications. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 A schematic diagram of the structure of a large field-of-view three-dimensional phase reconstruction system based on coherent modulation imaging provided in an embodiment of the present invention;

[0043] Figure 2 A flowchart of a large field-of-view three-dimensional phase reconstruction method based on coherent modulation imaging provided in an embodiment of the present invention;

[0044] Figure 3 A flowchart of one iteration provided for an embodiment of the present invention.

[0045] Symbol explanation: 1-Semiconductor laser source, 2-Spatial filtering and collimation system, 3-Beam splitter, 4-Probe, 5-Three-dimensional sample to be tested, 6-Phase modulator, 7-Detector, 8-Computer. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] This invention proposes a large field-of-view three-dimensional phase reconstruction system and method based on coherent modulation imaging. A two-dimensional electric translation stage is used to move the three-dimensional sample under test (extended sample), recording multiple diffraction patterns at different positions on the detector. Each diffraction pattern corresponds to the same distribution of the same modulator. During translation, there is some overlap between adjacent positions, and the overlapping portion remains unchanged between two measurements. Furthermore, this method can simultaneously reconstruct the complex field of the three-dimensional extended sample and the transmittance function of the modulator using an iterative projection algorithm, even when the modulator distribution is completely unknown. During reconstruction, a layered slicing method is used to reconstruct the phase of the three-dimensional extended sample. At each step of the iteration process, the sample function and modulator function of each layer are updated simultaneously, and the updated results are used in the next iteration calculation. Finally, the algorithm converges, reconstructing the complex amplitude of the sample and the modulator function. This new method will make coherent modulation imaging a more independent and practical diffraction imaging technique, broadening its applications in materials science, biomedicine, engineering measurement, and other fields.

[0049] Example 1

[0050] like Figure 1 As shown, this embodiment of the invention provides a large field-of-view three-dimensional phase reconstruction system based on coherent modulation imaging, including: a semiconductor laser source 1, a spatial filtering collimation system 2, a beam splitter 3, a probe 4, a two-dimensional translation stage, a phase modulator 6, a detector 7, and a computer 8.

[0051] The three-dimensional sample 5 to be tested is placed on a two-dimensional translation stage, which is used to move the three-dimensional sample 5 in two dimensions. After each translation of the three-dimensional sample 5 by the two-dimensional translation stage: the laser beam emitted by the semiconductor laser source 1 passes through the spatial filtering and collimation system 2 and outputs a plane wave; the plane wave is reflected by the beam splitter 3 to form an incident light wave, which passes sequentially through the probe 4 and the three-dimensional sample 5 to be tested, and the outgoing wave of the three-dimensional sample 5 to be tested reaches the phase modulator 6; the phase modulator 6 applies phase modulation to the outgoing wave and transmits it to the detector 7, where the diffraction pattern of the three-dimensional sample 5 at the scanning position is recorded; the scanning position is the position on the three-dimensional sample 5 to be tested where the incident light wave is irradiated. The detector 7 is connected to a computer 8, which is used to acquire the diffraction patterns of the three-dimensional sample 5 at different scanning positions recorded by the detector 7 after multiple translations of the three-dimensional sample 5 to be tested, and to reconstruct the phase of the three-dimensional sample 5 to be tested using a multi-layer slicing method.

[0052] Computer 8 is connected to a two-dimensional translation stage, and computer 8 controls the movement trajectory of the two-dimensional translation stage.

[0053] For example, computer 8 can control the exposure time of detector 7, thereby controlling the sampling frequency and sampling time (including the sampling end time). Detector 7 is preferably a CCD camera.

[0054] The specific experimental parameters are as follows: A laser beam emitted from a 532nm semiconductor laser source 1 (COHERENT, OBIS 532LS) passes through a spatial filtering collimation system 2 to output a plane wave, which is then reflected by a beam splitter 3BS (Beam Splitter) and irradiates the three-dimensional sample 5 to be tested. Figure 1 The dashed box indicates that the 3D sample was sliced ​​using a multi-layer slicing method, with each grid representing one slice. The 3D sample 5 under test was placed on an xy translation stage (DAHENG, GCD0401M), downstream of a 1mm probe 4. A phase modulator 6, fabricated from a quartz substrate, was placed at a certain distance behind the 3D sample 5. In the experiment, the phase modulator 6 was made of silicon glass using photolithography. Different etching depths on the substrate resulted in different phase delays. It roughly has a binary structure of 0 and π, and can produce a random phase delay of 0 / π for the incident light field of the working wavelength. It was designed to be randomly distributed, with each pixel measuring 16μm × 16μm. The final diffraction pattern was recorded by a CCD (Charge Coupled Device) camera (IMPERX IGV 6620B), with a pixel size of 5.5μm × 5.5μm. The CCD camera and the xy translation stage (two-dimensional translation stage) were controlled by a computer 8. The role of probe 4 is to limit the size of the light spot, which plays a constraining role in the spatial domain and speeds up the convergence of the algorithm.

[0055] Example 2

[0056] A large field-of-view three-dimensional phase reconstruction system (imaging optical path system) based on coherent modulation imaging, as described in Example 1, was built on an experimental platform. Based on the built imaging optical path system, this embodiment of the invention provides a large field-of-view three-dimensional phase reconstruction method based on coherent modulation imaging, such as... Figure 2 As shown, it includes:

[0057] Step 1: Determine the diffraction propagation distance of the large field-of-view three-dimensional phase reconstruction system.

[0058] The diffraction propagation distance of the large field-of-view three-dimensional phase reconstruction system is determined from multiple diffraction pattern samples using an autofocus and position registration algorithm. The diffraction propagation distance includes the interlayer spacing z0 of the three-dimensional sample, the diffraction propagation distance z1 between the three-dimensional sample and the phase modulator 6, and the diffraction propagation distance z2 between the phase modulator 6 and the detector.

[0059] Step 2: Obtain diffraction patterns at different positions of the three-dimensional sample 5 to be tested, and determine the scanning position of the three-dimensional sample 5 to be tested from each diffraction pattern.

[0060] Multiple diffraction patterns were recorded by moving the three-dimensional sample 5 under test multiple times. Then, experimental parameters such as the scanning position were obtained in advance from the measurement data through automatic focusing and position registration algorithms.

[0061] Step 3: Use a multi-layer slicing method to divide the three-dimensional sample 5 to be tested into layers.

[0062] Slices are cut along a direction parallel to the two-dimensional translation stage, and it is assumed that the distance between adjacent layers of all three-dimensional samples is equal, and the interlayer spacing of the three-dimensional samples is z0.

[0063] Step 4: Initialize the complex amplitude distribution of probe 4, the complex amplitude distribution of each layer of the three-dimensional sample 5 to be tested, and the transmittance function of phase modulator 6.

[0064] Step 5: Based on the scanning position, diffraction propagation distance, initialized complex amplitude distribution of probe 4, initialized complex amplitude distribution of each layer of the three-dimensional sample 5 to be tested, and initialized transmittance function of phase modulator 6 determined for each diffraction pattern, an iterative projection algorithm is used to reconstruct the complex field of each layer of the three-dimensional sample 5 to be tested at the scanning position and the transmittance function of the modulator.

[0065] For example, the specific process of reconstruction is as follows:

[0066] Based on the diffraction pattern, the scanning position determined by the diffraction pattern, the diffraction propagation distance, the initialized complex amplitude distribution of probe 4, the initialized complex amplitude distribution of each layer of the three-dimensional sample 5 to be tested, and the initialized transmittance function of phase modulator 6, the exit field of each layer of the three-dimensional sample 5 to be tested, the incident field of phase modulator 6, the exit field of phase modulator 6, and the planar light field of detector 7 are determined sequentially according to the propagation direction of light waves.

[0067] The planar light field of detector 7 is backpropagated to update the planar light field of detector 7, the output field of phase modulator 6, the incident field of phase modulator 6, and the output fields of each layer of the three-dimensional sample 5 to be tested in sequence.

[0068] Update the initial transmittance function based on the incident field of the updated phase modulator 6;

[0069] Based on the emission fields of each layer of the three-dimensional sample 5 before and after the update, update the initialized complex amplitude distribution of probe 4 and the initialized complex amplitude distribution of each layer of the three-dimensional sample 5 to complete one iteration;

[0070] The next iteration is performed based on the updated complex amplitude distribution of probe 4, the updated complex amplitude distribution of each layer of the three-dimensional sample 5, and the updated transmittance function, until the maximum number of iterations is reached or convergence is achieved, at which point the process ends.

[0071] Reference Figure 3 The flowchart for one iteration is shown below. The detailed steps of one iteration are as follows:

[0072] Step 1: Guess the complex amplitude distribution P of the probe and the complex amplitude distributions o1, o2...o of each layer of the three-dimensional sample. N And the transmittance function M of phase modulator 6, where N is the number of layers of the three-dimensional sample obtained by multi-layer slicing.

[0073] Step 2: After the incident light wave passes through probe P, it sequentially passes through each layer of the sample. The exit field of the Nth layer is...

[0074]

[0075] In the formula, This represents the emission field of the light wave after passing through the Nth layer, where n represents the nth region of the sample, j represents the jth iteration, and · indicates element-wise multiplication. Let z represent the wave propagation operator, which can be the angular spectrum propagation operator or the Fourier transform. z0 represents the interlayer spacing of the sample. We assume that the distance between each sample layer is equal.

[0076] Step 3: The sample-emitted wave reaches the modulator plane after diffraction at a distance of z1, and the incident light field distribution of the modulator is as follows:

[0077]

[0078] Step 4: Phase modulator 6 applies phase modulation to the optical field, resulting in a modulator output field.

[0079]

[0080] Step 5: The modulated light field continues to diffract and propagate forward a certain distance z2 to reach the detector 7 plane, where its light field distribution is as follows:

[0081]

[0082] Step 6: Apply intensity constraints to the light field in the detector 7 plane. Replace the iteratively estimated light field amplitude in the detector 7 plane with the square root of the acquired diffraction pattern, while keeping the phase unchanged, to obtain the updated light field distribution in the detector 7 plane.

[0083]

[0084] In the formula, I represents the updated optical field distribution on the 7-plane of the detector. n This represents the diffraction pattern collected from the nth region of the sample.

[0085] Step 7: Backpropagate the obtained light field to obtain the updated modulator output field.

[0086]

[0087] In the formula, This represents the reverse wave propagation operator.

[0088] Step 8: Update the modulator's transmittance function

[0089]

[0090]

[0091] In the formula, * represents complex conjugate operation, and α and β are feedback coefficients, which are generally taken as 1.

[0092] Step 9: Perform inverse diffraction on the updated modulator incident field to obtain the updated Nth layer exit field.

[0093]

[0094] Step 10: Continue backpropagating the updated Nth layer emission field and updating it layer by layer until the first layer is reached. This yields the updated material function and probe 4 distribution for each layer.

[0095]

[0096]

[0097]

[0098]

[0099] Repeat steps two through ten until all recorded diffraction patterns have been used, which is considered a completed iteration. The algorithm terminates when the predetermined number of iterations is completed or when convergence is achieved. The algorithm can be considered to have converged when the mean square error between the recovered diffraction pattern and the recorded diffraction pattern is sufficiently small or the correlation between the two is sufficiently high.

[0100] Step 6: Based on the complex field of each layer of the three-dimensional sample 5 under test at the scanning position, obtain the phase of each layer of the three-dimensional sample 5 under test, and form the three-dimensional phase of the three-dimensional sample 5 under test.

[0101] The present invention has the following technical effects:

[0102] 1. Strong independence: During reconstruction, both the sample function and the modulator function are updated simultaneously. An iterative projection algorithm is used to reconstruct the object's complex field and the modulator's transmittance function even with a completely unknown modulator distribution. The proposed method requires no prior information and operates independently without relying on other imaging methods. Under plane wave illumination, this method achieves a higher signal-to-noise ratio than traditional coherent modulation imaging.

[0103] 2. Large field of view: By translating the three-dimensional sample under test to acquire diffraction patterns at different positions, the imaging range is increased, overcoming the problem of small field of view in a single exposure of coherent modulation imaging. At the same time, the imaging resolution is also improved due to the redundancy of data.

[0104] 3. High adaptability: The phase reconstruction of three-dimensional thick samples is performed by layering and slicing, which enables the method to reconstruct not only two-dimensional non-expanded samples, but also the complex amplitude distribution of three-dimensional expanded samples of tens to hundreds of micrometers.

[0105] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0106] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A large field of view three-dimensional phase reconstruction system based on coherent modulation imaging, characterized in that, The system comprises a semiconductor laser source, a spatial filtering collimation system, a beam splitter, a probe, a two-dimensional translation stage, a phase modulator, a detector and a computer. The three-dimensional sample to be measured is arranged on the two-dimensional translation stage, which is used to drive the three-dimensional sample to be measured to translate in two dimensions; the three-dimensional sample to be measured is a three-dimensional thick sample. After the two-dimensional translation stage drives the three-dimensional sample to be measured to translate each time: the laser beam emitted by the semiconductor laser source passes through the spatial filtering collimation system to output a plane wave; the plane wave is reflected by the beam splitter to form an incident light wave, which passes through the probe and the three-dimensional sample to be measured in sequence, and the outgoing wave of the three-dimensional sample to be measured reaches the phase modulator; after the phase modulator applies phase modulation to the outgoing wave, the outgoing wave is transmitted to the detector, and the diffraction pattern of the scanning position of the three-dimensional sample to be measured is recorded in the detector; the scanning position is the position of the three-dimensional sample to be measured where the incident light wave is irradiated. The detector is connected to the computer, and the computer is used to obtain the diffraction patterns of different scanning positions of the three-dimensional sample to be measured recorded by the detector after the three-dimensional sample to be measured is translated multiple times, and reconstruct the phase of the three-dimensional sample to be measured by using a multi-slice method; during the reconstruction, the sample function and the modulator function are updated simultaneously, and the complex field of the three-dimensional sample to be measured and the transmittance function of the modulator are reconstructed simultaneously under the condition that the modulator distribution is completely unknown by using an iterative projection algorithm. The large-field three-dimensional phase reconstruction process based on coherent modulation imaging comprises: determining the diffraction propagation distance of the large-field three-dimensional phase reconstruction system; obtaining the diffraction patterns of different positions of the three-dimensional sample to be measured, and determining the scanning position of the three-dimensional sample to be measured from each diffraction pattern; layering the three-dimensional sample to be measured by using a multi-slice method; initializing the complex amplitude distribution of the probe, the complex amplitude distribution of each layer of the three-dimensional sample to be measured, and the transmittance function of the phase modulator; reconstructing the complex field of each layer of the three-dimensional sample to be measured at the scanning position and the transmittance function of the modulator by using an iterative projection algorithm for each diffraction pattern according to the scanning position determined from each diffraction pattern, the diffraction propagation distance, the initialized complex amplitude distribution of the probe, the initialized complex amplitude distribution of each layer of the three-dimensional sample to be measured, and the initialized transmittance function of the phase modulator; obtaining the phase of each layer of the three-dimensional sample to be measured according to the complex field of each layer of the three-dimensional sample to be measured at the scanning position, and constituting the three-dimensional phase of the three-dimensional sample to be measured. The computer is connected to the two-dimensional translation stage; 2. The large field of view three-dimensional phase reconstruction system based on coherent modulation imaging of claim 1, wherein, The computer is used to control the movement trajectory of the two-dimensional translation stage. The detector is a CCD camera.

3. The large field of view three-dimensional phase reconstruction system based on coherent modulation imaging of claim 1, wherein, The large-field three-dimensional phase reconstruction method based on coherent modulation imaging applies the large-field three-dimensional phase reconstruction system based on coherent modulation imaging according to any one of claims 1-3, and the large-field three-dimensional phase reconstruction method based on coherent modulation imaging comprises:

4. A large field of view three-dimensional phase reconstruction method based on coherent modulation imaging, characterized in that, determining the diffraction propagation distance of the large-field three-dimensional phase reconstruction system; obtaining the diffraction patterns of different positions of the three-dimensional sample to be measured, and determining the scanning position of the three-dimensional sample to be measured from each diffraction pattern; layering the three-dimensional sample to be measured by using a multi-slice method; initializing the complex amplitude distribution of the probe, the complex amplitude distribution of each layer of the three-dimensional sample to be measured, and the transmittance function of the phase modulator; ​ reconstructing the complex field of each layer of the three-dimensional sample to be measured at the scanning position and the transmittance function of the phase modulator by using an iterative projection algorithm for each diffraction pattern according to the scanning position determined for each diffraction pattern, the diffraction propagation distance, the initialized complex amplitude distribution of the probe, the initialized complex amplitude distribution of each layer of the three-dimensional sample to be measured, and the initialized transmittance function of the phase modulator; obtaining the phase of each layer of the three-dimensional sample to be measured according to the complex field of each layer of the three-dimensional sample to be measured at the scanning position, and constructing the three-dimensional phase of the three-dimensional sample to be measured.

5. The method of claim 4, wherein, The diffraction propagation distance of the large-field three-dimensional phase reconstruction system is determined, and specifically includes the following steps: The diffraction propagation distance of the large-field three-dimensional phase reconstruction system is determined from the multiple diffraction pattern samples by using an automatic focusing and position registration algorithm; the diffraction propagation distance includes the layer spacing of the three-dimensional sample, the diffraction propagation distance between the three-dimensional sample and the phase modulator, and the diffraction propagation distance between the phase modulator and the detector.

6. The method of claim 4, wherein, The complex field of each layer of the three-dimensional sample to be measured at the scanning position and the transmittance function of the phase modulator are reconstructed by using an iterative projection algorithm for each diffraction pattern according to the scanning position determined for each diffraction pattern, the diffraction propagation distance, the initialized complex amplitude distribution of the probe, the initialized complex amplitude distribution of each layer of the three-dimensional sample to be measured, and the initialized transmittance function of the phase modulator, and specifically includes the following steps: According to the diffraction pattern, the scanning position determined for the diffraction pattern, the diffraction propagation distance, the initialized complex amplitude distribution of the probe, the initialized complex amplitude distribution of each layer of the three-dimensional sample to be measured, and the initialized transmittance function of the phase modulator, the outgoing field of each layer of the three-dimensional sample to be measured, the incoming field of the phase modulator, the outgoing field of the phase modulator, and the planar light field of the detector are sequentially determined in the propagation direction of the light wave; The planar light field of the detector is back-propagated to sequentially update the planar light field of the detector, the outgoing field of the phase modulator, the incoming field of the phase modulator, and the outgoing field of each layer of the three-dimensional sample to be measured; The initialized transmittance function is updated according to the updated incoming field of the phase modulator; The initialized complex amplitude distribution of the probe and the initialized complex amplitude distribution of each layer of the three-dimensional sample to be measured are updated according to the outgoing field of each layer of the three-dimensional sample to be measured before and after the update, and one iteration is completed. The next iteration is performed according to the updated complex amplitude distribution of the probe, the updated complex amplitude distribution of each layer of the three-dimensional sample to be measured, and the updated transmittance function, until the maximum number of iterations is reached or convergence is achieved, and the process ends.

7. The method of claim 6, wherein, The outgoing field of each layer of the three-dimensional sample to be measured, the incoming field of the phase modulator, the outgoing field of the phase modulator, and the planar light field of the detector, which are sequentially determined in the propagation direction of the light wave, are as follows: Emission fields of each layer of the three-dimensional sample under test: In the formula, Indicates that the light wave passes through the first... N The launch field behind the layer, n The third dimension of the three-dimensional sample to be tested n Each scan location j Indicates the first j In the next iteration, the symbol · indicates element-wise multiplication. Let z denote the wave propagation operator, and z0 denote the interlayer spacing of the three-dimensional sample. This represents the complex amplitude distribution of the probe. O N Indicates the three-dimensional sample to be tested. N Complex amplitude distribution of the layer; incident field of the phase modulator: ; where represents the incident field of the phase modulator, and z1 represents the diffractive propagation distance between the three-dimensional sample and the phase modulator; exit field of the phase modulator: wherein denotes the exit field of the phase modulator, denotes the transmittance function of the phase modulator; the planar light field of the probe: ; wherein denotes the planar light field of the probe, and z2 denotes the diffractive propagation distance between the phase modulator and the probe.

8. The large-field three-dimensional phase reconstruction method based on coherent modulation imaging according to claim 7, characterized in that, The updated planar light field of the detector is: wherein represents the updated planar light field of the detector, represents the diffraction pattern collected at the i-th scanning position of the three-dimensional sample to be measured, n represents the diffraction pattern collected at the i-th scanning position of the three-dimensional sample to be measured, The exit field of the updated phase modulator is where denotes the exit field of the updated phase modulator, denotes the inverse wave propagation operator; The incident field of the updated phase modulator is: wherein, denotes the incident field of the updated phase modulator, denotes the complex conjugate operation, denotes the first feedback coefficient; The exit field of each layer of the updated three-dimensional sample to be measured is: ; wherein, represents the exit field of the updated first layer of the three-dimensional sample to be measured. N represents the exit field of the updated first layer of the three-dimensional sample to be measured.

9. The method of claim 8, wherein, The transmittance function update formula of the phase modulator is: In the formula, represents the updated transmittance function, represents the second feedback coefficient.

10. The large-field three-dimensional phase reconstruction method based on coherent modulation imaging according to claim 9, characterized in that, The update formula for the complex amplitude distribution of each layer of the three-dimensional sample under test is as follows: In the formula, Indicates the three-dimensional sample to be tested. N Complex amplitude distribution of the layer; The update formula for the probe complex amplitude distribution is: In the formula, Indicates the three-dimensional sample to be tested. N The updated probe complex amplitude distribution corresponding to the layer.

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