Polarization measurement device and method based on biprism interference and diffraction

Abstract

The invention discloses a polarization measurement device and method based on biprism interference and diffraction. The device comprises a light barrier, a biprism with a polarizing film, a polarizing film and a CCD detector which are sequentially arranged along the direction of a light path, a slit is formed in the light barrier, and other parts, except the slit, of the light barrier are light-proof; a polarization film is attached to the side, facing the light barrier, of the surface of the biprism. Incident light sequentially passes through the slit on the light barrier, the polarization film, the biprism and the polarizer and then is imaged on the CCD detector. Polarization measurement is realized through the light barrier with the slit, the biprism with the polarization film, the polaroid and the CCD detector which are sequentially arranged along the light path direction, so that the accuracy and efficiency of polarization measurement are improved.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a polarization measurement device and method based on double prism interference and diffraction. Background Art

[0002] Light beams consist of oscillating electric and magnetic fields that are always perpendicular to each other as they propagate along an axis. Polarization generally refers to the shape that the fields take as they propagate toward an observer located along the axis of the beam's propagation. The polarization state of a light beam plays an important role in a wide range of applications, such as quantum and classical communications, remote sensing, astronomy, and biomedical diagnostics. The type of polarization is determined by the electric field used as a reference. For example, linear polarization means that the electric field oscillates in a single orientation from the observer's point of view. In circular or elliptical types of polarization, the electric field rotates in the shape of a corresponding circle or ellipse.

[0003] Since polarized light is of great significance in scientific research and industrial production, the detection of the polarization state of incident polarized light becomes particularly important.

[0004] The most commonly used method at present is the Stokes parameter measurement method. Its measurement principle is to adjust the polarizer and the optical axis direction of the 1 / 4 wave plate in the optical path to be measured, measure the transmitted light intensity, and calculate the Stokes parameter of the light to be measured by calculating the output signal. During measurement, at least 6 sets of light intensity values ​​can be obtained by rotating the optical axis of the polarizer and the fast axis direction of the 1 / 4 wave plate in the optical path; or the incident light can be split first, and each beam of light can be measured after passing through a fixed polarizer with different optical axis and fast axis directions and a 1 / 4 wave plate combination to obtain the light intensity.

[0005] However, the above existing solutions need to change the direction of the polarizer optical axis and the fast axis of the 1 / 4 wave plate multiple times during measurement, which increases the error of polarization measurement. And because of the use of a 1 / 4 wave plate, a specific device can only measure light of a specific wavelength. When measuring light of other wavelengths, the 1 / 4 wave plate corresponding to the wavelength needs to be replaced, and the fast axis direction of the 1 / 4 wave plate needs to be re-determined, which greatly limits the efficiency and accuracy of polarization light measurement. Therefore, how to design a method to improve the accuracy and efficiency of polarization measurement is a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide a polarization measurement device and method based on double prism interference and diffraction, and realize polarization measurement by means of a light-blocking plate with slits, a double prism with a polarization film, a polarizer and a CCD detector arranged in sequence along the light path direction, thereby improving the accuracy and efficiency of polarization measurement.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A polarization measurement device based on double prism interference and diffraction, comprising a light blocking plate, a double prism with a polarization film, a polarizer and a CCD detector arranged in sequence along the light path direction;

[0009] A slit is provided on the light blocking plate, and other parts of the light blocking plate except the slit are not light-transmissive;

[0010] A polarizing film is attached to the side of the double prism surface facing the light-blocking plate;

[0011] The incident light passes through the slit on the light-blocking plate, the polarizing film, the double prism and the polarizing plate in sequence, and then forms an image on the CCD detector.

[0012] The present invention also discloses a polarization measurement method based on double prism interference and diffraction, which is implemented based on the polarization measurement device of the present invention and specifically includes:

[0013] S1: A light blocking plate, a double prism with a polarizing film, a polarizing plate and a CCD detector are sequentially arranged along the light path direction;

[0014] S2: The incident light is irradiated onto the light-blocking plate. After the incident light passes through the slit, polarizing film, biprism and polarizing plate on the light-blocking plate in sequence, it is imaged on the CCD detector to collect the interference image.

[0015] S3: Calculate the interference intensity model and diffraction intensity model of any point on the CCD detector by using double-slit interference theory and Fraunhofer diffraction theory respectively;

[0016] S4: The data in the interference image is brought into the interference intensity model or the diffraction intensity model for fitting to obtain the polarization state of the incident light.

[0017] Preferably, in step S3, the formula of the interference intensity model is expressed as:

[0018]

[0019] Where: I φ (p) represents the interference intensity; E x represents the amplitude of the electric vector along the x-axis; E y represents the amplitude of the electric vector along the y-axis; α represents E y Relative to E x The leading phase; φ represents the angle between the optical axis of the polarizer in front of the CCD and the y-axis; θ represents the angle between the light and the z-axis; γ represents the angle between the optical axis of the polarizing film and the x-axis; w represents the distance between the two slits; and k represents the wave number of the incident light.

[0020] Preferably, in step S3, the formula of the diffraction intensity model is expressed as:

[0021]

[0022]

[0023] Where: I y (p) represents the diffraction intensity; E x represents the amplitude of the electric vector along the x-axis; E y represents the amplitude of the electric vector along the y-axis; α represents E y Relative to E x The leading phase; θ represents the angle between the light and the z-axis; γ represents the angle between the optical axis of the polarizing film and the x-axis; w represents the spacing between adjacent slits; k represents the wave number of the incident light; λ represents the wavelength of the incident light; a represents the width of the slit; L1 and L2 represent the optical paths of the two special light rays; c1 and c2 are constants.

[0024] Preferably, in step S4, the data in the interference image is brought into the interference intensity model or the diffraction intensity model for fitting to obtain the amplitude E of the electric vector component along the x-axis. x , the amplitude E of the electric vector along the y-axis y and E y Relative to E x The leading phase α of the incident light is then determined.

[0025] Preferably, in step S4, the polarization state of the incident light includes linearly polarized light, circularly polarized light and elliptically polarized light.

[0026] Compared with the prior art, the polarization measurement device and method based on double prism interference and diffraction in the present invention have the following beneficial effects:

[0027] The present invention realizes polarization measurement of incident light by sequentially setting a light-blocking plate, a double prism with a polarization film, a polarizer and a CCD detector along the optical path. First, the slit on the light-blocking plate plays a role in limiting light, which helps to reduce the interference of stray light and background light, thereby improving the accuracy and efficiency of polarization measurement. Secondly, the double prism can divide the incident light into two coherent light beams, which will interfere with each other in the subsequent propagation process. The polarization film modulates the polarization state of one of the incident light beams, so that the two coherent light beams generated by the double prism have different polarization characteristics. Then, the two light beams are polarized and interfered at the polarizer in front of the CCD. The interference image and interference or diffraction formula collected by the CCD can fit and obtain the polarization type of the incident light, and can also minimize errors and improve the accuracy of polarization measurement. Finally, the CCD detector is used to capture and record interference patterns. Its high resolution and sensitivity can capture subtle changes in interference fringes, providing high-quality raw data for subsequent image processing and data analysis.

[0028] In summary, the polarization measurement device and method of the present invention can significantly improve the accuracy and efficiency of polarization measurement by limiting light through a slit and utilizing a double prism with a polarization film, a polarizer, and a CCD detector; by observing and analyzing interference patterns and combining the fitting of an interference intensity model and a diffraction intensity model, it can accurately identify whether the incident light is linearly polarized, circularly polarized, or elliptically polarized; the device has a simple structure and is easy to operate, and is suitable for a variety of polarization measurement scenarios, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the purpose, technical solution and advantages of the invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0030] Figure 1 It is a schematic diagram of the structure of a polarization measurement device based on double prism interference and diffraction;

[0031] Figure 2 Schematic diagram of the optical axis direction of the polarizing film;

[0032] Figure 3 This is the interference image detected by the CCD detector when the slit width is large;

[0033] Figure 4 This is the interference image detected by the CCD detector when the slit width is small;

[0034] Figure 5 The interference image when the optical axis of the polarizing film and the y-axis are at 0 degrees when the interference phenomenon is dominant;

[0035] Figure 6 The interference image is when the optical axis of the polarizing film is 50 degrees to the y-axis when the interference phenomenon is dominant;

[0036] Figure 7 Schematic diagram of nonlinear least squares fitting of experimental data light intensity and diffraction angle when the diffraction phenomenon is dominant. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but only represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0038] The following is a further detailed description through specific implementation methods:

[0039] Embodiment 1:

[0040] This embodiment discloses a polarization measurement device based on double prism interference and diffraction.

[0041] like Figure 1 As shown, a polarization measurement device based on double prism interference and diffraction includes a light blocking plate, a double prism with a polarization film, a polarizer, and a CCD detector which are sequentially arranged along the light path direction;

[0042] A slit is provided on the light blocking plate, and other parts of the light blocking plate except the slit are not light-transmissive;

[0043] A polarizing film is attached to the side of the double prism surface facing the light blocking plate; wherein the transmission axis of the polarizing film is as follows Figure 2 shown.

[0044] The incident light passes through the slit on the light-blocking plate, the polarizing film, the double prism and the polarizing plate in sequence, and then forms an image on the CCD detector.

[0045] According to the characteristics of the slit light source passing through the double prism, it can be equivalent to the interference and diffraction of two parallel slits on the light blocking plate.

[0046] The present invention realizes polarization measurement of incident light by sequentially setting a light-blocking plate, a double prism with a polarization film, a polarizer and a CCD detector along the optical path. First, the slit on the light-blocking plate plays a role in limiting light, which helps to reduce the interference of stray light and background light, thereby improving the accuracy and efficiency of polarization measurement. Secondly, the double prism can divide the incident light into two coherent light beams, which will interfere with each other in the subsequent propagation process. The polarization film modulates the polarization state of one of the incident light beams, so that the two coherent light beams generated by the double prism have different polarization characteristics. Then, the two light beams are polarized and interfered at the polarizer in front of the CCD. The interference image and interference or diffraction formula collected by the CCD can fit and obtain the polarization type of the incident light, and can also minimize errors and improve the accuracy of polarization measurement. Finally, the CCD detector is used to capture and record interference patterns. Its high resolution and sensitivity can capture subtle changes in interference fringes, providing high-quality raw data for subsequent image processing and data analysis.

[0047] In summary, the polarization measurement device and method of the present invention can significantly improve the accuracy and efficiency of polarization measurement by limiting light through a slit and utilizing a double prism with a polarization film, a polarizer, and a CCD detector; by observing and analyzing interference patterns and combining the fitting of an interference intensity model and a diffraction intensity model, it can accurately identify whether the incident light is linearly polarized, circularly polarized, or elliptically polarized; the device has a simple structure and is easy to operate, and is suitable for a variety of polarization measurement scenarios, and has broad application prospects.

[0048] Embodiment 2:

[0049] Based on the first embodiment, this embodiment discloses a polarization measurement method based on double prism interference and diffraction.

[0050] Polarization measurement methods based on dual prism interference and diffraction, including:

[0051] S1: A light blocking plate, a double prism with a polarizing film, a polarizing plate and a CCD detector are sequentially arranged along the light path direction;

[0052] S2: The incident light is irradiated onto the light blocking plate. After passing through the slit, polarizing film, biprism and polarizing plate on the light blocking plate in sequence, the incident light is imaged on the CCD detector to collect the interference image. According to the characteristics of the slit light source passing through the biprism, it can be equivalent to the interference and diffraction of the two parallel slits on the light blocking plate.

[0053] S3: Calculate the interference intensity model and diffraction intensity model of any point on the CCD detector by using double-slit interference theory and Fraunhofer diffraction theory respectively;

[0054] S4: The data in the interference image is brought into the interference intensity model or the diffraction intensity model for fitting to obtain the polarization state of the incident light.

[0055] In this embodiment, the interference image collected by the CCD detector is a photograph, which is converted into grayscale data through Matlab, and a formula can be used to fit the data to obtain the polarization state of the incident light. Figure 3 This is the interference image detected by the CCD detector when the slit width is large. At this time, double-slit interference is dominant, and the double-slit interference formula can be used to fit the polarization state of the incident light. Figure 4 This is the interference image detected by the CCD detector when the slit width is small. At this time, the diffraction phenomenon is obvious, and the double-slit diffraction formula can be used to fit the polarization state of the incident light.

[0056] Specifically, the data in the interference image are fitted into the interference intensity model or the diffraction intensity model to obtain the amplitude E of the electric vector along the x-axis component. x , the amplitude E of the electric vector along the y-axis y and E y Relative to E xThe leading phase α of the incident light determines the polarization state of the incident light. The polarization states of the incident light include linear polarization, circular polarization, and elliptically polarized light. If α is zero, it is linear polarization; if α is not 0, it is elliptically polarized light; if α is π / 2 and E y =E x , then it is circularly polarized light.

[0057] The present invention realizes polarization measurement of incident light by sequentially setting a light-blocking plate, a double prism with a polarization film, a polarizer and a CCD detector along the optical path. First, the slit on the light-blocking plate plays a role in limiting light, which helps to reduce the interference of stray light and background light, thereby improving the accuracy and efficiency of polarization measurement. Secondly, the double prism can divide the incident light into two coherent light beams, which will interfere with each other in the subsequent propagation process. The polarization film modulates the polarization state of one of the incident light beams, so that the two coherent light beams generated by the double prism have different polarization characteristics. Then, the two light beams are polarized and interfered at the polarizer in front of the CCD. The interference image and interference or diffraction formula collected by the CCD can fit and obtain the polarization type of the incident light, and can also minimize errors and improve the accuracy of polarization measurement. Finally, the CCD detector is used to capture and record interference patterns. Its high resolution and sensitivity can capture subtle changes in interference fringes, providing high-quality raw data for subsequent image processing and data analysis.

[0058] In summary, the polarization measurement device and method of the present invention can significantly improve the accuracy and efficiency of polarization measurement by limiting light through a slit and utilizing a double prism with a polarization film, a polarizer, and a CCD detector; by observing and analyzing interference patterns and combining the fitting of an interference intensity model and a diffraction intensity model, it can accurately identify whether the incident light is linearly polarized, circularly polarized, or elliptically polarized; the device has a simple structure and is easy to operate, and is suitable for a variety of polarization measurement scenarios, and has broad application prospects.

[0059] In the specific implementation process, the formula of the interference intensity model is expressed as:

[0060]

[0061] Where: I φ (p) represents the interference intensity; E x represents the amplitude of the electric vector along the x-axis; E y represents the amplitude of the electric vector along the y-axis; α represents E y Relative to E x The leading phase; φ represents the angle between the optical axis of the polarizer in front of the CCD and the y-axis; θ represents the angle between the light and the z-axis; γ represents the angle between the optical axis of the polarizing film and the x-axis; w represents the distance between the two slits; and k represents the wave number of the incident light.

[0062] Specifically, the theoretical formula of the interference intensity model is derived as follows:

[0063] when Figure 1 When the slit width of the middle light-blocking plate is large, parallel light shines on the ridge of the double prism, and it is considered that there are two virtual light sources S1 and S2. At this time, the slit width of S1 and S2 is ignored.

[0064] Polarized light can be expressed as

[0065] Where E x is the amplitude of the electric vector component along the x-axis; E y is the amplitude of the electric vector component along the y-axis, α is E y Relative to E x The leading phase.

[0066] When the transmission direction of the polarization film in front of the CCD detector is at an angle φ to the y-axis, any point p (such as Figure 1 The interference intensity of

[0067] I(p)=I φ (p) (1)

[0068] I φ (p) can be expressed in the form of complex amplitude as follows:

[0069] I φ (p)=(U 1φ +U 2φ )(U 1φ +U 2φ )* (2)

[0070] After the polarized light passes through the polarization film and the biprism (the first slit S1), it reaches point p of the CCD detector. The complex amplitude component along the y-axis at an angle of φ is U 1φ :

[0071] U 1φ =E x cosysin(γ+φ)+E y e iα sinysin(γ+φ)e i(wt-kL) (3)

[0072] After the polarized light passes through the polarization film and the biprism (the second slit S2), it reaches point p of the CCD detector. The complex amplitude component in the direction with an angle of φ with the y-axis is U 2φ :

[0073] U 2φ =E x sin(φ)+E y e iα cos(φ)ei(wt-kL2) (4) According to double-slit interference and the above equation, the interference intensity of completely polarized light at point p is:

[0074]

[0075] Experimental verification of the interference intensity model:

[0076] It is known that the incident light is linearly polarized light passing through a polarizer, and the transmission axis of the polarizer is 45° with the y-axis. x With E y The ratio should be 1 and α should be 0°.

[0077] Figure 5 It is the interference image collected when the transmission axis of the polarization film in front of the CCD detector is 0° with the y-axis. After grayscale processing, the relationship between the grayscale value and the pixel point is shown in Table 1.

[0078] Table 1

[0079]

[0080] Figure 6 The interference image is collected when the transmission axis of the polarization film in front of the CCD detector is 50° with the y-axis. After grayscale processing, the relationship between the grayscale value and the pixel point is shown in Table 2.

[0081] Table 2

[0082]

[0083] When φ=0, the transmission axis of the polarizer in front of the CCD detector is along the y-axis:

[0084]

[0085]

[0086] When the transmission axis of the CCD front polarizer forms an angle φ with the y-axis

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] According to the known light intensity, four equations can be determined. By solving the nonlinear equations using Matlab, E can be determined.x 、E y , α, and then determine the polarization state of the incident light. Use MATLAB to bring the data in the interference image into the interference intensity model for fitting, and we get:

[0093] E x =11.348040

[0094] E y =11.112074

[0095] α=0.000074°

[0096] Among them, E x With E y The ratio of ( is 1.01, which is very close to 1, and α is 0.000074°, which is very close to 0°. It can be determined that the incident light is linearly polarized light, which is consistent with the facts and the experiment is accurate.

[0097] In the specific implementation process, the formula of the diffraction intensity model is expressed as:

[0098]

[0099]

[0100] Where: I y (p) represents the diffraction intensity; E x represents the amplitude of the electric vector along the x-axis; E y represents the amplitude of the electric vector along the y-axis; α represents E y Relative to E x The leading phase; θ represents the angle between the light and the z-axis; γ represents the angle between the optical axis of the polarizing film and the x-axis; w represents the spacing between adjacent slits; k represents the wave number of the incident light; λ represents the wavelength of the incident light; a represents the width of the slit; L1 and L2 represent the optical paths of the two special light rays; c1 and c2 are constants.

[0101] Specifically, the theoretical formula of the diffraction intensity model is derived as follows:

[0102] when Figure 1 When the slit width of the middle light-blocking plate is small, the diffraction phenomenon of light is obvious.

[0103] When parallel light hits the ridge of the biprism, it is considered that there are two virtual light sources, S1 and S2. At this time, the slit width of the light source is considered.

[0104] Polarized light can be expressed as

[0105] When the transmission direction of the polarization film in front of the CCD detector is along the y-axis (i.e., 0° with the y-axis), any point p (such as Figure 1The diffraction intensity of (shown) is:

[0106] I(p)=I y (p) (6)

[0107] Among them I y (p) is the diffraction intensity of the completely polarized light in the y direction.

[0108] I y (p) can be expressed in the form of complex amplitude as follows:

[0109] I y (p)=(U 1y +U 2y )(U 1y +U 2y ) * (7)

[0110] After the polarized light passes through the polarization film and the biprism (the first slit S1), it reaches point p of the CCD detector. The complex amplitude component in the y-axis direction is:

[0111]

[0112] After the polarized light passes through the polarization film and the biprism (the second slit S2), it reaches point p of the CCD detector. The complex amplitude component in the y-axis direction is:

[0113]

[0114] According to Fraunhofer diffraction and the above equation, the diffraction intensity of polarized light at point p is:

[0115]

[0116] Experimental verification of the diffraction intensity model:

[0117] It is known that the incident light is linearly polarized light passing through a polarizer, and the projection axis of the polarizer is -35° with the y-axis. x With E y The ratio should be 0.7 and α should be 180°.

[0118] The interference image is collected by the CCD detector. After grayscale processing, the relationship between the light intensity value and the diffraction angle is shown in Table 3.

[0119] Table 3

[0120]

[0121]

[0122] According to formula (10), Matlab is used to perform nonlinear least squares fitting on the experimental data of light intensity and diffraction angle. The fitting results are as follows: Figure 7 shown.

[0123] The data in the interference image is brought into the diffraction intensity model for fitting through MATLAB, and the following is obtained:

[0124] E x =61.454545

[0125] E y =82.545455

[0126] α=175°

[0127] Root mean square error (RMSE): 3.1529

[0128] Among them, E x With E y The ratio is 0.74, α is 175°, and the fitting E x With E y Ratio and actual E x With E y The ratio of 0.7 is very close, and α is very close to 180°. It can be determined that the incident light is linearly polarized light, which is consistent with the facts and the experiment is accurate.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A polarization measurement device based on double prism interference and diffraction, characterized in that: It includes a light blocking plate, a double prism with a polarizing film, a polarizing plate and a CCD detector which are sequentially arranged along the light path direction; A slit is provided on the light blocking plate, and other parts of the light blocking plate except the slit are not light-transmissive; A polarizing film is attached to the side of the double prism surface facing the light-blocking plate; The incident light passes through the slit on the light-blocking plate, the polarizing film, the double prism and the polarizing plate in sequence, and then forms an image on the CCD detector.

2. A polarization measurement method based on double prism interference and diffraction, characterized in that: Based on the implementation of the polarization measurement device described in claim 1, it specifically includes: S1: A light blocking plate, a double prism with a polarizing film, a polarizing plate and a CCD detector are sequentially arranged along the light path direction; S2: The incident light is irradiated onto the light-blocking plate. After the incident light passes through the slit, polarizing film, biprism and polarizing plate on the light-blocking plate in sequence, it is imaged on the CCD detector to collect the interference image. S3: Calculate the interference intensity model and diffraction intensity model of any point on the CCD detector by using double-slit interference theory and Fraunhofer diffraction theory respectively; S4: The data in the interference image is brought into the interference intensity model or the diffraction intensity model for fitting to obtain the polarization state of the incident light.

3. The polarization measurement method based on double prism interference and diffraction as claimed in claim 2, characterized in that: In step S3, the formula of the interference intensity model is expressed as: Where: I φ (p) represents the interference intensity; E x represents the amplitude of the electric vector along the x-axis; E y represents the amplitude of the electric vector along the y-axis; α represents E y Relative to E x The leading phase; φ represents the angle between the optical axis of the polarizer in front of the CCD and the y-axis; θ represents the angle between the light and the z-axis; γ represents the angle between the optical axis of the polarizing film and the x-axis; w represents the distance between the two slits; and k represents the wave number of the incident light.

4. The polarization measurement method based on double prism interference and diffraction as claimed in claim 2, characterized in that: In step S3, the formula of the diffraction intensity model is expressed as: Where: I y (p) represents the diffraction intensity; E x represents the amplitude of the electric vector along the x-axis; E y represents the amplitude of the electric vector along the y-axis; α represents E y Relative to E x The leading phase; θ represents the angle between the light and the z-axis; γ represents the angle between the optical axis of the polarizing film and the x-axis; w represents the spacing between adjacent slits; k represents the wave number of the incident light; λ represents the wavelength of the incident light; a represents the width of the slit; L1 and L2 represent the optical paths of the two special light rays; c1 and c2 are constants.

5. The polarization measurement method based on double prism interference and diffraction as claimed in claim 3 or 4, characterized in that: In step S4, the data in the interference image is brought into the interference intensity model or the diffraction intensity model for fitting to obtain the amplitude E of the electric vector along the x-axis component. x , the amplitude E of the electric vector along the y-axis y and E y Relative to E x The leading phase α of the incident light is then determined.

6. The polarization measurement method based on double prism interference and diffraction as claimed in claim 5, characterized in that: In step S4, the polarization state of the incident light includes linear polarized light, circular polarized light and elliptically polarized light.

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