A spherical wave exposure interference field online control system and control method

Abstract

The present application provides an online control system and method for the spherical wave exposure interference field. The incident light passes through a beam splitting grating to obtain two beams of diffracted light. The two beams of diffracted light are incident on a spatial filter and are expanded into spherical waves. The two beams of spherical waves form Moiré fringes on the surface of the reference grating. The phase of the two diffracted light beams is changed by fine-tuning the position of the beam splitting grating to achieve phase shift. A camera is used to capture the Moiré fringe image obtained by phase shift, and the Moiré fringe phase distribution is extracted from the image. The coefficients of the line distribution function are fitted based on the extracted phase information. The value of the recording parameter is roughly measured as the initial value, and a local optimization is performed to obtain the actual value of the recording parameter. Based on the actual value of the recording parameter obtained by measurement, the spatial position of the spatial filter is automatically calibrated. After multiple measurements and calibrations, the measurement results of the recording parameters are close to the target value, thereby realizing online control of the exposure interference field and improving measurement accuracy and efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of holographic grating manufacturing, and in particular to an online control system and control method for a spherical wave exposure interference field. Background Art

[0002] Holographic aberration-corrected gratings (HAGs) exhibit both dispersive and convergent properties, offering significant advantages in reducing the number of components in spectrometer systems, improving signal-to-noise ratio, and increasing energy efficiency. With in-depth research in fields such as synchrotron radiation and deep space exploration, spectroscopic instruments are developing towards higher precision, higher resolution, and smaller size. The aberration correction capabilities of HAGs are becoming increasingly prominent. The fabrication process of a holographic aberration-corrected grating involves superimposing two coherent spherical laser beams on a substrate coated with a photosensitive material to form an interference field. The incident angles of the two beams vary with the substrate's position, generating interference fringes with a periodic pattern in both the tangential and sagittal dimensions. Through exposure and development steps, the distribution of the interference fringes is converted into a grating's line density. The spatial position of the spherical beams determines the interference field distribution, directly influencing the grating's line density and, consequently, the aberration correction capability of the HAGs. However, errors in the spatial position of the two beams during the manipulation of the exposure interference field can reduce the aberration correction capability, limiting the fabrication and application of HAGs.

[0003] Traditional non-online control methods measure the density of grating lines created by the exposure interference field and then re-correct the exposure interference field based on the measurement results. However, this method has significant limitations. First, current line density detection methods are limited by quality defects in the grating grooves, motion errors of the translation stage, and alignment errors in the measurement optical path, resulting in relatively large errors in the measurement results. Second, errors in the line density distribution cannot directly reflect errors in the interference field recording parameters. As a result, the measurement results of the non-online method cannot accurately assist the interference field control process, and it is necessary to rely on the experience of the assembler to make repeated corrections to complete the control.

[0004] Current online control methods utilize the Moiré fringes generated by a reference grating and the exposure interference field to invert and calculate the spatial position information of the spherical beam, thereby online correcting the exposure interference field based on the measurement results. However, this method is highly dependent on the computational efficiency and accuracy of the inversion algorithm employed. Existing methods require orthogonalization of discrete phase data, resulting in a large computational load and large relative errors in the measurement results, making them insufficient to meet the growing demand for precision and efficiency in controlling the exposure interference field of aberration-corrected gratings. These issues make it difficult to achieve high-precision and efficient control of the exposure interference field. Summary of the Invention

[0005] In view of this, it is necessary to provide an online control system and control method for the spherical wave exposure interference field that can effectively improve the measurement accuracy and efficiency, in order to address the current defects of relatively low control accuracy and efficiency of the aberration-corrected grating exposure interference field.

[0006] To solve the above problems, this application adopts the following technical solutions:

[0007] One of the purposes of the present application is to provide an online control system for a spherical wave exposure interference field, comprising a laser (1), a beam splitting grating (2), a first reflector (3), a second reflector (4), a third reflector (5), a fourth reflector (6), a first beam position detector (713), a first spatial filter (714), a second beam position detector (723), a second spatial filter (724), a reference grating (8), a CCD camera (9), and a controller (10);

[0008] The incident light emitted by the laser (1) passes through the beam splitting grating (2) to obtain a first diffracted light and a second diffracted light;

[0009] The first diffracted light passes through the first reflecting mirror (3) and the third reflecting mirror (5) in sequence, and then enters the first beam position detector (713) and the first spatial filter (714) in sequence;

[0010] The second diffracted light passes through the second reflector (4), the fourth reflector (6) in sequence, and then passes through the second beam position detector (723) and the second spatial filter (724);

[0011] Two diffracted light beams incident on the first spatial filter (714) and the second spatial filter (724) respectively are expanded into spherical waves, and the two spherical waves form Moiré fringes on the surface of the reference grating (8);

[0012] Finely adjusting the position of the beam splitting grating (2) to change the phases of the two diffracted light beams to achieve phase shift;

[0013] The CCD camera (9) captures the phase shift to obtain a Moiré fringe image;

[0014] The controller (10) can capture a Moiré fringe image obtained by phase shifting according to the CCD camera (9), extract the Moiré fringe phase distribution from the Moiré fringe image using a phase shift algorithm, and fit the line distribution function coefficient according to the extracted phase information; roughly measure the value of the recording parameter as an initial value, and use a reconstruction algorithm to perform local optimization to obtain the actual value of the recording parameter; automatically calibrate the spatial positions of the first spatial filter (714) and the second spatial filter (724) based on the measured actual value of the recording parameter; and after multiple measurements and calibrations, make the recording parameter measurement result close to the target value, thereby realizing online control of the exposure interference field.

[0015] In some embodiments, a rotation module (7) is further included, wherein the rotation module (7) includes a first rotation arm (71), a second rotation arm (72) and a turntable (73), wherein the first rotation arm (71) and the second rotation arm (72) can rotate with the turntable (73) as the center, and the first rotation arm (71) is provided with a first linear guide rail (711) and a first slider (712), wherein the first slider (712) can slide along the first linear guide rail (711), and the first slider (712) is also provided with the first light beam position detector (713) and the first spatial filter (714), and the second rotation arm (72) is provided with a second linear guide rail (721) and a second slider (722), wherein the second slider (722) can slide along the second linear guide rail (721), and the second light beam position detector (723) and the second spatial filter (724) are also provided with the second slider (722).

[0016] In some embodiments, the first beam position detector (713) is composed of a first beam splitting prism and a first position sensitive detector, and the first spatial filter (714) is composed of a first objective lens and a first pinhole; the second beam position detector (723) is composed of a second beam splitting prism and a second position sensitive detector, and the second spatial filter (724) is composed of a second objective lens and a second pinhole.

[0017] In some embodiments, the first diffracted light passes through the first reflector (3) and the third reflector (5) in sequence and then enters the first beam splitter prism, wherein a portion of the light beam is incident on the first position sensitive detector through the first beam splitter prism, and another portion of the light beam is transmitted through the first beam splitter prism and then passes through the first objective lens and then vertically enters the reference grating through the first pinhole and is reflected by the reference grating and then reflected by the first beam splitter prism to the first position sensitive detector;

[0018] The second diffracted light passes through the second reflector (4) and the fourth reflector (6) in sequence and then enters the two-beam splitting prism, wherein a portion of the light beam passes through the second beam splitting prism and enters the second position-sensitive detector, and another portion of the light beam is transmitted through the second beam splitting prism and then passes through the second objective lens and then vertically enters the reference grating through the second pinhole and is reflected by the reference grating and then reflected by the second beam splitting prism to the second position-sensitive detector.

[0019] In some embodiments, the beam splitting grating (2) can be fine-tuned by a piezoelectric actuator to achieve a change in position.

[0020] A second object of the present application is to provide an online control method for the spherical wave exposure interference field online control system, comprising the following steps:

[0021] The incident light emitted by the laser (1) passes through the beam splitting grating (2) to obtain a first diffracted light and a second diffracted light;

[0022] The first diffracted light passes through the first reflecting mirror (3) and the third reflecting mirror (5) in sequence, and then enters the first beam position detector (713) and the first spatial filter (714) in sequence;

[0023] The second diffracted light passes through the second reflector (4), the fourth reflector (6) in sequence, and then passes through the second beam position detector (723) and the second spatial filter (724);

[0024] Two diffracted light beams incident on the first spatial filter (714) and the second spatial filter (724) respectively are expanded into spherical waves, and the two spherical waves form Moiré fringes on the surface of the reference grating (8);

[0025] By fine-tuning the position of the beam splitting grating (2), the phases of the two diffracted light beams are changed to achieve phase shift;

[0026] The CCD camera (9) captures the phase shift to obtain a Moiré fringe image;

[0027] The controller (10) can capture a Moiré fringe image obtained by phase shifting according to the CCD camera (9), extract the Moiré fringe phase distribution from the Moiré fringe image using a phase shift algorithm, and fit the line distribution function coefficient according to the extracted phase information; roughly measure the value of the recording parameter as an initial value, and use a reconstruction algorithm to perform local optimization to obtain the actual value of the recording parameter; automatically calibrate the spatial positions of the first spatial filter (714) and the second spatial filter (724) based on the measured actual value of the recording parameter; and after multiple measurements and calibrations, make the recording parameter measurement result close to the target value, thereby realizing online control of the exposure interference field.

[0028] This application adopts the above technical solution, and its beneficial effects are as follows:

[0029] The present application provides an online control system and control method for the spherical wave exposure interference field. The incident light passes through a beam splitting grating to obtain two beams of diffracted light. The two beams of diffracted light pass through two mirrors and are incident on a spatial filter and expanded into spherical waves. The two beams of spherical waves form Moiré fringes on the surface of a plane equidistant reference grating. The position of the beam splitting grating is fine-tuned by a piezoelectric actuator, thereby changing the phase of the two diffracted light beams to achieve phase shift. A CCD camera is used to capture the Moiré fringe image obtained by phase shift, and a phase shift algorithm is used to extract the Moiré fringe phase distribution from the image, and the line distribution function coefficient is fitted based on the extracted phase information. The value of the recording parameter is roughly measured as the initial value, and a reconstruction algorithm is used to perform local optimization to obtain the actual value of the recording parameter. According to the measured actual value of the recording parameter, the spatial position of the first spatial filter and the second spatial filter is automatically calibrated. After multiple measurements and calibrations, the recording parameter measurement results are close to the target values, realizing online control of the exposure interference field, improving the measurement accuracy and efficiency of the recording parameters, and assisting the online control of the spherical wave exposure interference field to realize automatic online control of the spherical wave exposure interference field, thereby greatly shortening the production cycle of the aberration-corrected grating and reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 A schematic structural diagram of the spherical wave exposure interference field online control system provided in an embodiment of the present application.

[0032] Figure 2This is a parameter diagram of the spherical wave exposure interference field recording provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0034] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0036] In order to make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below with reference to the accompanying drawings and embodiments.

[0037] See also Figure 1 The structural diagram of the spherical wave exposure interference field online control system provided in the embodiment of the present application includes: a laser (1), a beam splitting grating (2), a first reflector (3), a second reflector (4), a third reflector (5), a fourth reflector (6), a first beam position detector (713), a first spatial filter (714), a second beam position detector (723), a second spatial filter (724), a reference grating (8), a CCD camera (9) and a controller (10). The specific implementation method is described in detail below.

[0038] The incident light emitted by the laser (1) passes through the beam splitting grating (2) to obtain a first diffracted light and a second diffracted light; the first diffracted light passes through the first reflector (3) and the third reflector (5) in sequence and then enters the first beam position detector (713) and the first spatial filter (714) in sequence; the second diffracted light passes through the second reflector (4) and the fourth reflector (6) in sequence and then enters the second beam position detector (723) and the second spatial filter (724) in sequence; the two diffracted light beams incident on the first spatial filter (714) and the second spatial filter (724) respectively are expanded into spherical waves, and the two spherical waves form Moiré fringes on the surface of the reference grating (8); the position of the beam splitting grating (2) is fine-tuned, from The phases of the two diffracted light beams are changed to achieve phase shift; the CCD camera (9) photographs the phase shift to obtain a Moiré fringe image; the controller (10) can extract the Moiré fringe phase distribution from the Moiré fringe image based on the Moiré fringe image obtained by photographing the phase shift by the CCD camera (9), and fit the line distribution function coefficient according to the extracted phase information; roughly measure the value of the recording parameter as an initial value, and use the reconstruction algorithm to perform local optimization to obtain the actual value of the recording parameter; based on the measured actual value of the recording parameter, automatically calibrate the spatial positions of the first spatial filter (714) and the second spatial filter (724); after multiple measurements and calibrations, the recording parameter measurement result is close to the target value, thereby realizing online control of the exposure interference field.

[0039] In a specific embodiment, a rotation module (7) is further included. The rotation module (7) includes a first rotation arm (71), a second rotation arm (72) and a turntable (73). The first rotation arm (71) and the second rotation arm (72) can rotate around the turntable (73). The first rotation arm (71) is equipped with a first linear guide rail (711) and a first slider (712). The first slider (712) can slide along the first linear guide rail (711). The first slider (712) is also equipped with the first light beam position detector (713) and the first spatial filter (714). The second rotation arm (72) is equipped with a second linear guide rail (721) and a second slider (722). The second slider (722) can slide along the second linear guide rail (721). The second slider (722) is also equipped with the second light beam position detector (723) and the second spatial filter (724).

[0040] It can be understood that in practice, the positions of the first rotating arm (71) and the second rotating arm (72) are adjusted by rotating the first rotating arm (71) and the second rotating arm (72), so as to better receive the incident diffracted light beam; and the positions of the first slider (712) and / or the second slider (722) on the linear guide rail are adjusted to the appropriate positions of the beam position detector and the spatial filter, so as to better utilize the diffracted light beam.

[0041] In a specific embodiment, the first beam position detector (713) is composed of a first beam splitting prism and a first position sensitive detector, and the first spatial filter (714) is composed of a first objective lens and a first pinhole; the second beam position detector (723) is composed of a second beam splitting prism and a second position sensitive detector, and the second spatial filter (724) is composed of a second objective lens and a second pinhole.

[0042] In a specific embodiment, the first diffracted light passes through the first reflector (3) and the third reflector (5) in sequence and then enters the first beam splitter prism, wherein a portion of the light beam passes through the first beam splitter prism and enters the first position sensitive detector, and another portion of the light beam transmits through the first beam splitter prism and then passes through the first objective lens and then vertically enters the reference grating from the first pinhole, and is reflected by the reference grating and then reflected by the first beam splitter prism to the first position sensitive detector; the second diffracted light passes through the second reflector (4) and the fourth reflector (6) in sequence and then enters the second beam splitter prism, wherein a portion of the light beam passes through the second beam splitter prism and enters the second position sensitive detector, and another portion of the light beam transmits through the second beam splitter prism and then passes through the second objective lens and then vertically enters the reference grating from the second pinhole, and is reflected by the reference grating and then reflected by the second beam splitter prism to the second position sensitive detector.

[0043] In a specific embodiment, the beam splitting grating (2) can be fine-tuned by a piezoelectric actuator to achieve a change in position.

[0044] It should be noted that: in some specific embodiments, the system includes a rotation module (7), which is composed of two sets of automatically controlled first rotation arms (71), second rotation arms (72) and turntables (73). Each rotation arm can rotate around the turntable to adjust the recording angle. A linear guide rail and a slider are installed on the rotation arm. The slider can move along the guide rail to adjust the recording arm length. A beam position detector and a spatial filter are installed on the slider. The incident light beam is split into two beams by a planar equidistant beam splitting grating (2), and the beam splitting grating (2) is installed on a piezoelectric actuator. The two light beams are reflected by a reflector and enter the beam position detector (first beam position detector (713) and second beam position detector (723)) for calibrating the angle of the rotation arm. The beam position detector is composed of a beam splitting prism BS and a position sensitive detector. After the position calibration is completed, the two light beams pass through spatial filters (first spatial filter (714) and second spatial filter (724)) composed of an objective lens and a pinhole, respectively, so that the two plane light beams are converted into good spherical light beams and form Moiré fringes on the reference grating surface.

[0045] It can be understood that the spatial distribution of the two spatial filters relative to the center of the grating substrate determines the phase distribution of the spherical wave exposure interference field. The parameters representing their spatial positions are the recording parameters. A planar, equally spaced reference grating is used in place of the grating substrate. Its groove density corresponds to the target value of the incident angle at the center of the two spherical wave interference fields, forming Moiré fringes with the interference field. Once the exposure interference field is regulated, the reference grating is replaced with the grating substrate for exposure.

[0046] See also Figure 2 , is the parameter diagram of the spherical wave exposure interference field recording proposed by the present invention. Figure 2 As shown in Figure 1, the spatial distribution of the two spatial filters relative to the center of the grating substrate determines the phase distribution of the spherical wave exposure interference field. The parameters representing their spatial positions are called recording parameters. rC and rD are the lengths of CO and DO, respectively, and are called recording arm lengths. γ and δ are the angles between CO and DO and the xOz plane, respectively. α and β are the angles between CO and DO and the xOy plane, respectively, and are called recording angles.

[0047] This application uses a planar, equally spaced reference grating in place of a grating substrate. Its line density corresponds to the target angle of incidence at the center of the interference field between two spherical waves, forming Moiré fringes with the interference field. A five-step phase shifting method is used to calculate the phase distribution of the Moiré fringe image, extract the phase information of the measured interference field, fit the line distribution function coefficients, and invert the exposure interference field recording parameters using an iterative reconstruction algorithm.

[0048] Specifically, the online control process of the system is as follows:

[0049] 1) The reference grating (8), the turntable (73) and the first rotating arm (71) are respectively rotated to a recording angle γ, the first slider (712) is controlled to move so that the distance between the pinhole center of the first spatial filter (714) and the center of the reference grating (8) is approximately the recording arm length rC, the position of the first reflector (3) and / or the third reflector (5) is adjusted so that the reflected light passes through the first beam splitting prism of the first beam position detector (713), wherein a portion of the light beam is incident on the first position sensitive detector, and the other portion of the light beam is perpendicularly incident on the reference grating (8) and reflected by the first beam splitting prism and then reflected to the first position sensitive detector. By adjusting the position of the first reflector (3) and / or the third reflector (5), the light spot centers of the reference beam and the measurement beam in the position sensitive detector are made to coincide; the second rotating arm (72) is similarly regulated to achieve coarse adjustment of the second rotating arm length and the recording angle.

[0050] 2) The reference grating (8) and the turntable (73) are rotated to zero position, and the first spatial filter (714) and the second spatial filter (724) are installed to generate a spherical wave interference field, thereby generating Moiré fringes on the surface of the reference grating (8). The beam splitting grating (2) is moved in a direction perpendicular to the direction of its scribed lines by a piezoelectric actuator, so that the step value of the spherical wave interference field is π / 2, and five Moiré fringe images on the surface of the reference grating (8) are captured by a camera. In order to ensure the signal-to-noise ratio of the extracted fringes, only the fringe area with the highest contrast in the Moiré fringe image is selected when extracting phase information. The five Moiré fringe images are subjected to region selection and filtering, and the phase data corresponding to the Moiré fringes are extracted by a five-step phase shift and unwrapping algorithm.

[0051] 3) Fitting the line distribution function coefficients and iteratively reconstructing the recording parameters are performed on the selected portion of the Moiré fringe phase distribution data. After multiple iterative calculations, the line distribution function coefficients converge to obtain the recording parameter measurement results. The recording parameters of the exposure interference field center are calculated based on the spatial position relationship between the center of the selected area and the center of the reference grating. Based on the measurement results, the exposure interference field recording parameters are automatically adjusted by adjusting the positions of the first rotating arm (71), the second rotating arm (72), the first slider (712), and the second slider (722). After multiple measurements and adjustments, the recording parameter measurement results are close to the target value.

[0052] The spherical wave exposure interference field online control system and method provided in the above embodiment of the present application has been simulated and found that the recording parameter measurement method adopted by the system can improve the relative error of the measurement accuracy to less than 1×10 -8 , which greatly improves the measurement accuracy. The experimental results are analyzed and the variance of the multiple measurement results of the arm length is less than 1×10 -2 , the variance of the recorded angles is less than 1×10-6 , proving that the system has high accuracy. The wavefront phase corresponding to the recorded parameter measurement results and the wavefront phase error extracted by the phase shift method meet PV<1×10 -3 rad, RMS<1×10 -4 rad, demonstrating the high accuracy of the system. The exposure interference field can be fully regulated after less than three measurements and calibrations, demonstrating the system's ability to achieve high-precision and efficient regulation of the exposure interference field.

[0053] The present application provides an online control system and control method for the spherical wave exposure interference field. The incident light passes through a beam splitting grating to obtain two beams of diffracted light. The two beams of diffracted light pass through two mirrors and are incident on a spatial filter and expanded into spherical waves. The two beams of spherical waves form Moiré fringes on the surface of a plane equidistant reference grating. The position of the beam splitting grating is fine-tuned by a piezoelectric actuator, thereby changing the phase of the two diffracted light beams to achieve phase shift. A CCD camera is used to capture the Moiré fringe image obtained by phase shift, and a phase shift algorithm is used to extract the Moiré fringe phase distribution from the image, and the line distribution function coefficient is fitted based on the extracted phase information. The value of the recording parameter is roughly measured as the initial value, and a reconstruction algorithm is used to perform local optimization to obtain the actual value of the recording parameter. According to the measured actual value of the recording parameter, the spatial position of the first spatial filter and the second spatial filter is automatically calibrated. After multiple measurements and calibrations, the recording parameter measurement results are close to the target values, realizing online control of the exposure interference field, improving the measurement accuracy and efficiency of the recording parameters, and assisting the online control of the spherical wave exposure interference field to realize automatic online control of the spherical wave exposure interference field, thereby greatly shortening the production cycle of the aberration-corrected grating and reducing the production cost.

[0054] It can be understood that the various technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A spherical wave exposure interference field online control system, characterized in that: It comprises a laser (1), a beam splitting grating (2), a first reflector (3), a second reflector (4), a third reflector (5), a fourth reflector (6), a first beam position detector (713), a first spatial filter (714), a second beam position detector (723), a second spatial filter (724), a reference grating (8), a CCD camera (9), and a controller (10); The incident light emitted by the laser (1) passes through the beam splitting grating (2) to obtain a first diffracted light and a second diffracted light; The first diffracted light sequentially passes through the first reflector (3) and the third reflector (5) and then sequentially enters the first beam position detector (713) and the first spatial filter (714); The second diffracted light passes through the second reflector (4) and the fourth reflector (6) in sequence and then enters the second beam position detector (723) and the second spatial filter (724) in sequence; Two diffracted light beams are incident on the first spatial filter (714) and the second spatial filter (724) respectively and are expanded into spherical waves, the two spherical waves forming Moiré fringes on the surface of the reference grating (8); Fine-tuning the position of the beam splitting grating (2) to change the phase of the two diffracted beams to achieve phase shift; The CCD camera (9) captures the phase shift to obtain a Moiré fringe image; The controller (10) can capture a Moiré fringe image obtained by phase shifting according to the CCD camera (9), extract the Moiré fringe phase distribution from the Moiré fringe image using a phase shift algorithm, and fit the line distribution function coefficient based on the extracted phase information; roughly measure the value of the recording parameter as an initial value, and use a reconstruction algorithm to perform local optimization to obtain the actual value of the recording parameter; wherein the spatial position distribution of the two spatial filters relative to the center of the grating base determines the phase distribution of the spherical wave exposure interference field, and the parameter representing its spatial position is called the recording parameter; based on the measured actual value of the recording parameter, automatically calibrate the spatial position of the first spatial filter (714) and the second spatial filter (724); after multiple measurements and calibrations, the recording parameter measurement result is close to the target value, thereby realizing online control of the exposure interference field; The system further comprises a rotation module (7), wherein the rotation module (7) comprises a first rotation arm (71), a second rotation arm (72) and a turntable (73), wherein the first rotation arm (71) and the second rotation arm (72) can rotate with the turntable (73) as the center, wherein a first linear guide rail (711) and a first slider (712) are mounted on the first rotation arm (71), wherein the first slider (712) can slide along the first linear guide rail (711), and wherein the first light beam position detector (713) and the first spatial filter (714) are also mounted on the first slider (712), wherein a second linear guide rail (721) and a second slider (722) are mounted on the second rotation arm (72), wherein the second slider (722) can slide along the second linear guide rail (721), and wherein the second light beam position detector (723) and the second spatial filter (724) are also mounted on the second slider (722).

2. The spherical wave exposure interference field online control system according to claim 1, characterized in that: The first beam position detector (713) is composed of a first beam splitting prism and a first position sensitive detector, and the first spatial filter (714) is composed of a first objective lens and a first pinhole; the second beam position detector (723) is composed of a second beam splitting prism and a second position sensitive detector, and the second spatial filter (724) is composed of a second objective lens and a second pinhole.

3. The spherical wave exposure interference field online control system according to claim 2, characterized in that: The first diffracted light passes through the first reflector (3) and the third reflector (5) in sequence and then enters the first beam splitter prism, wherein a portion of the light beam is incident on the first position sensitive detector through the first beam splitter prism, and another portion of the light beam is transmitted through the first beam splitter prism and then passes through the first objective lens and then vertically enters the reference grating through the first pinhole and is reflected by the reference grating and then reflected by the first beam splitter prism to the first position sensitive detector; The second diffracted light passes through the second reflector (4) and the fourth reflector (6) in sequence and then enters the two-beam splitting prism, wherein a part of the light beam passes through the second beam splitting prism and enters the second position sensitive detector, and the other part of the light beam is transmitted through the second beam splitting prism and then passes through the second objective lens and then vertically enters the reference grating through the second pinhole and is reflected by the reference grating and then reflected by the second beam splitting prism to the second position sensitive detector.

4. The spherical wave exposure interference field online control system according to claim 1, characterized in that: The beam splitting grating (2) can be fine-tuned by a piezoelectric actuator to achieve a change in position.

5. An online control method for the spherical wave exposure interference field online control system according to claim 1, characterized in that: The steps include: The incident light emitted by the laser (1) passes through the beam splitting grating (2) to obtain a first diffracted light and a second diffracted light; The first diffracted light sequentially passes through the first reflector (3) and the third reflector (5) and then sequentially enters the first beam position detector (713) and the first spatial filter (714); The second diffracted light passes through the second reflector (4) and the fourth reflector (6) in sequence and then enters the second beam position detector (723) and the second spatial filter (724) in sequence; Two diffracted light beams are incident on the first spatial filter (714) and the second spatial filter (724) respectively and are expanded into spherical waves, the two spherical waves forming Moiré fringes on the surface of the reference grating (8); By fine-tuning the position of the beam splitting grating (2), the phases of the two diffracted light beams are changed to achieve phase shift; The CCD camera (9) captures the phase shift to obtain a Moiré fringe image; The controller (10) can capture a Moiré fringe image obtained by phase shifting using the CCD camera (9), extract the Moiré fringe phase distribution from the Moiré fringe image using a phase shift algorithm, and fit the line distribution function coefficient based on the extracted phase information; roughly measure the value of the recording parameter as an initial value, and use a reconstruction algorithm to perform local optimization to obtain the actual value of the recording parameter; automatically calibrate the spatial positions of the first spatial filter (714) and the second spatial filter (724) based on the measured actual value of the recording parameter; and after multiple measurements and calibrations, make the recording parameter measurement result close to the target value, thereby realizing online control of the exposure interference field.

Images