Faraday rotation deflection angle measuring method and device

Abstract

The invention discloses a Faraday optical rotation deflection angle measurement method and device, and the method comprises the steps: arranging quartz glass on a propagation path of Faraday optical rotation, determining an incident angle of the Faraday optical rotation to the quartz glass, carrying out the gain of an actual deflection angle of the Faraday optical rotation through the quartz glass, and obtaining the deflection angle of the Faraday optical rotation; the gain multiple corresponds to the incident angle of the Faraday rotation to the quartz glass; imaging the gained Faraday optical rotation to obtain an optical rotation image; and determining a deflection angle after gain according to the optical rotation image, and reversely deducing an actual deflection angle of the Faraday optical rotation according to the deflection angle after gain, the incident angle of the Faraday optical rotation emitted to the quartz glass and a corresponding relation between the gain multiple and the incident angle of the Faraday optical rotation emitted to the quartz glass. According to the invention, reliable measurement of small-angle Faraday rotation can be realized.

Description

Technical Field

[0001] The invention belongs to the field of magnetic field measurement, and in particular relates to a method and a device for measuring a Faraday rotation deflection angle. Background Art

[0002] Faraday rotation is the phenomenon that the polarization plane of polarized light rotates when passing through a magneto-optical medium. The magnetic field measurement method based on the Faraday effect has been widely used in z-pinch experiments and laboratory pulse power generator astrophysics experiments due to its extremely high spatial resolution and non-invasiveness. One of the main directions for the next stage of development of Faraday rotation diagnosis is how to achieve small-angle measurement of optical rotation in low-density magneto-optical media.

[0003] Existing two-dimensional magnetic field measurement devices based on Faraday rotation diagnosis mainly use focal plane amplitude splitting polarimeter and time-sharing polarizer. The time-sharing polarizer obtains high-quality polarization images by setting polarizers at different angles in front of the sensor and collecting multiple images, but it is not suitable for scenes with rapid changes in polarization direction. The focal plane amplitude splitting polarimeter uses multiple sensors or a sub-region sensor to capture images filtered by polarizers at different angles, thereby realizing polarization imaging. This method uses a polarization beam splitter to separate P polarization and S polarization, and then different CCD sensors capture P polarization and S polarization to determine the linear polarization angle, but there is still no better measurement method for measuring the deflection angle of small-angle optical rotation generated by low-density magneto-optical media. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a method and device for measuring the deflection angle of Faraday rotation, which can realize reliable measurement of small-angle Faraday rotation.

[0005] In order to solve the above technical problems, the present invention is implemented by the following technical solutions: According to a first aspect of the present invention, a method for measuring a Faraday rotation deflection angle is provided, comprising: Quartz glass is arranged on the propagation path of Faraday rotation light, and the incident angle of Faraday rotation light to the quartz glass is determined, and the actual deflection angle of Faraday rotation light is amplified by using the quartz glass, and the gain multiple has a corresponding relationship with the incident angle of Faraday rotation light to the quartz glass; Imaging the Faraday rotation after gain to obtain an optical rotation image; The deflection angle after gain is determined according to the optical rotation image, and the actual deflection angle of the Faraday rotation is inferred according to the deflection angle after gain, the incident angle of the Faraday rotation to the quartz glass, and the corresponding relationship between the gain multiple and the incident angle of the Faraday rotation to the quartz glass.

[0006] In a possible implementation manner of the first aspect, when the quartz glass is provided, an incident angle of the Faraday rotation light to the quartz glass is 52° to 54°.

[0007] In a possible implementation manner of the first aspect, the corresponding relationship between the gain multiple and the incident angle of the Faraday rotation light onto the quartz glass is determined by the following method: a. deflecting all P polarized light at a known angle to obtain simulated optical rotation, wherein the deflection angle of the simulated optical rotation is the known angle; b. directing the simulated optical rotation toward the quartz glass, determining the incident angle of the simulated optical rotation toward the quartz glass, and using the quartz glass to gain the deflection angle of the simulated optical rotation; c. imaging the simulated optical rotation after gain to obtain a simulated optical rotation image; d. determining the deflection angle of the simulated optical rotation after gain according to the simulated optical rotation image; e. Determine the relationship between the incident angle of the simulated optical rotation directed to the quartz glass and the gain multiple based on the known angle and the deflection angle of the simulated optical rotation after gain; f. For different incident angles, repeat steps b to e to obtain a series of relationships between the incident angles of the simulated optical rotation incident on the quartz glass and the corresponding gain multiples, that is, the corresponding relationship between the gain multiple and the incident angle of the Faraday optical rotation incident on the quartz glass is obtained.

[0008] In a possible implementation manner of the first aspect, an anti-reflection film is coated on the incident surface of the quartz glass.

[0009] In a possible implementation manner of the first aspect, a cross section of the quartz glass is a wedge-shaped surface.

[0010] In a possible implementation manner of the first aspect, imaging the Faraday rotation light after the actual deflection angle is subjected to gain is specifically: A charge-coupled device image sensor equipped with a pixelated polarizer is used to image the Faraday rotation of the actual deflection angle after gain to obtain a rotation image.

[0011] In a possible implementation manner of the first aspect, before determining the deflection angle after gain according to the optical rotation image, the method further includes: Bilinear interpolation is performed on the optical rotation image to complete the spatial resolution.

[0012] In a possible implementation manner of the first aspect, determining the deflection angle after gain according to the optical rotation image is specifically: The polarization state is determined by analyzing the pixel grayscale value of the optical rotation image, thereby obtaining the Faraday optical rotation deflection angle distribution.

[0013] According to a second aspect of the present invention, there is provided a Faraday rotation deflection angle measuring device, comprising: A Faraday rotation emission component, used for generating Faraday rotation; Quartz glass is arranged on the propagation path of Faraday rotation light, and the incident angle of Faraday rotation light to the quartz glass is determined. The quartz glass is used to gain the actual deflection angle of Faraday rotation light, and the gain multiple has a corresponding relationship with the incident angle of Faraday rotation light to the quartz glass; An optical rotation imaging component is arranged on the propagation path of the Faraday rotation light after being reflected by the quartz glass, and is used to image the Faraday rotation light after the actual deflection angle is amplified; The processing module is used to determine the deflection angle after gain according to the optical rotation image, and reversely infer the actual deflection angle of the Faraday optical rotation according to the deflection angle after gain, the incident angle of the Faraday optical rotation to the quartz glass, and the corresponding relationship between the gain multiple and the incident angle of the Faraday optical rotation to the quartz glass.

[0014] In a possible implementation of the second aspect, the Faraday rotation light emitting assembly includes a beam expander, a half-wave plate, a full P polarizer, a vacuum chamber, and a magneto-optical medium disposed in the vacuum chamber, which are sequentially disposed on the laser propagation path along the laser propagation path; the laser light is converted into full P polarized light after passing through the full P polarizer; and the full P polarized light is converted into Faraday rotation light after passing through the magneto-optical medium in the vacuum chamber; The optical rotation imaging component includes a convex lens arranged on the propagation path of the Faraday rotation light after being reflected by the quartz glass, and a charge coupled device image sensor equipped with a pixelated polarizer arranged behind the convex lens.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides a method for measuring the Faraday rotation deflection angle. By cleverly using quartz glass to gain the deflection angle of Faraday rotation, the small-angle rotation that was originally difficult to measure can be amplified, thereby greatly improving the measurement accuracy. It is particularly suitable for small-angle rotation measurement under low-density magneto-optical media, filling the gap in the prior art in this field. By adjusting the angle of the detection light incident on the quartz glass, the gain multiple of the rotation angle can be flexibly adjusted to adapt to different experimental conditions and measurement requirements, so that the present invention can be widely used in various Faraday rotation measurement scenarios, including z-pinch experiments, laboratory pulse power generator astrophysical experiments, etc. The measurement method of the present invention does not rely on complex polarization imaging systems, such as focal plane amplitude polarimeter or time-sharing polarizer, but can be realized using simple quartz glass and imaging technology, which not only simplifies the measurement device and reduces the cost, but also improves the flexibility of measurement, so that it can be applied to more different experimental scenarios and conditions. In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the following is a preferred embodiment, and in conjunction with the attached drawings, a detailed description is given as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the description of the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is an optical path diagram of a Faraday rotation deflection angle measurement device according to an embodiment of the present invention; Figure 2 A diagram of an array of pixelated polarizers provided in an embodiment of the present invention; Figure 3 FIG. 4 is a graph showing the relationship between the incident angle of Faraday rotation light onto the quartz glass and the gain factor according to an embodiment of the present invention.

[0018] 1 is a beam expander; 2 is detection light; 3 is a half-wave plate; 4 is a full P polarizer; 5 is a vacuum chamber; 6 is a magneto-optical medium; 7 is quartz glass; 8 is a convex lens; 9 is a charge-coupled device image sensor equipped with a pixelated polarizer; 10 is a Faraday rotation channel; 11 is a 90° polarizer; 12 is a 45° polarizer; 13 is a 135° polarizer; 14 is a 0° polarizer; 15 is a super pixel unit. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The embodiment of the present invention provides a method for measuring the Faraday rotation deflection angle, which is mainly to solve the problem in the prior art that it is difficult to achieve small-angle rotation measurement under low-density magneto-optical media. By introducing quartz glass as a gain medium, the deflection characteristics of quartz glass to light are cleverly utilized to enhance the deflection angle of Faraday rotation, thereby improving the measurement sensitivity. The specific process includes: Step 1, quartz glass is arranged on the propagation path of Faraday rotation, and the incident angle of Faraday rotation to the quartz glass is determined, and the actual deflection angle of Faraday rotation is amplified by using the quartz glass, and the gain multiple has a corresponding relationship with the incident angle of Faraday rotation to the quartz glass; Step 2, imaging the Faraday rotation after gain to obtain an optical rotation image; Step 3: determine the deflection angle after gain according to the optical rotation image, and reversely infer the actual deflection angle of the Faraday optical rotation according to the deflection angle after gain, the incident angle of the Faraday optical rotation onto the quartz glass, and the corresponding relationship between the gain multiple and the incident angle of the Faraday optical rotation onto the quartz glass.

[0021] That is to say, this method arranges quartz glass on the propagation path of Faraday rotation and utilizes the deflection gain characteristics of quartz glass to amplify the actual deflection angle of Faraday rotation. Then, the optical rotation image is obtained through imaging technology, and the deflection angle after gain is determined accordingly. Finally, the actual deflection angle of Faraday rotation is inferred by combining the known corresponding relationship between the incident angle, gain multiple and incident angle.

[0022] Specifically, a quartz glass is placed on the propagation path of the Faraday rotation light, and the incident angle of the Faraday rotation light to the quartz glass is accurately measured. The quartz glass produces a deflection gain effect on the incident Faraday rotation light, and the gain multiple has a clear corresponding relationship with the incident angle, which is determined in advance by experiments. The Faraday rotation light after the quartz glass gain is imaged to obtain an optical rotation image. Through image processing, the deflection angle in the optical rotation image is measured, that is, the deflection angle after gain. According to the deflection angle after gain, the incident angle, and the corresponding relationship between the gain multiple and the incident angle. For example, for Faraday rotation light with an actual deflection angle of 2°, the quartz glass is captured at an incident angle of 52°. It is known that when the incident angle is 52°, the gain of the quartz glass on the deflection angle of Faraday rotation light is 10 times, and the deflection angle after gain is 20°.

[0023] In one possible implementation, when quartz glass is set, the incident angle of Faraday rotation light to the quartz glass is 52° to 54°. Specifically, within this angle range, quartz glass has a significant gain effect on the deflection angle of Faraday rotation light, and the gain multiple is between 10 times and 22 times, which not only ensures the obvious gain of the deflection angle, making the measurement more sensitive and accurate, but also avoids the noise problems such as self-luminescence and scattered light that may be caused by excessive gain multiples, thereby improving the signal-to-noise ratio of the measurement.

[0024] Specifically, the gain multiple relationship when the incident angle is 52°~54°, combined with Figure 3 And as shown in Table 1.

[0025] Table 1

[0026] In one possible implementation, the corresponding relationship between the gain multiple and the incident angle of the Faraday rotation light onto the quartz glass is determined by the following method: a. Deflecting the full P polarized light at a known angle to obtain simulated optical rotation, wherein the deflection angle of the simulated optical rotation is the known angle.

[0027] That is to say, full P polarized light (i.e. polarized light parallel to the incident plane) is used as the initial light source. The full P polarized light is deflected at a known angle to obtain simulated optical rotation. The deflection angle of the simulated optical rotation is the known deflection angle, which is used for subsequent gain multiple calculations.

[0028] b. Directing the simulated optical rotation to the quartz glass, determining the incident angle of the simulated optical rotation to the quartz glass, and using the quartz glass to gain the deflection angle of the simulated optical rotation.

[0029] That is, the prepared simulated optical rotation is directed to the quartz glass, and the incident angle of the simulated optical rotation to the quartz glass is measured. The deflection angle of the simulated optical rotation is amplified by the quartz glass.

[0030] c. Imaging the simulated optical rotation after gain to obtain a simulated optical rotation image.

[0031] That is to say, the simulated optical rotation after the deflection angle is gained is imaged to obtain a simulated optical rotation image.

[0032] d. Determine the deflection angle of the simulated optical rotation after gain based on the simulated optical rotation image.

[0033] e. Determine the relationship between the incident angle of the simulated optical rotation onto the quartz glass and the gain multiple based on the known angle and the deflection angle of the simulated optical rotation after gain.

[0034] That is, the gain multiple is calculated according to the known angle (ie, the initial deflection angle of the simulated optical rotation) and the deflection angle of the simulated optical rotation after gain, and the gain multiple is equal to the deflection angle after gain divided by the known angle.

[0035] f. For different incident angles, repeat steps b to e to obtain a series of relationships between the incident angles of the simulated optical rotation incident on the quartz glass and the corresponding gain multiples, that is, the corresponding relationship between the gain multiple and the incident angle of the Faraday optical rotation incident on the quartz glass is obtained.

[0036] That is to say, for different incident angles, repeat the above steps to obtain a series of relationships between the incident angles of simulated optical rotation incident on the quartz glass and the corresponding gain multiples. Record the gain multiple at each incident angle, and draw a curve or table of the relationship between the incident angle and the gain multiple, so as to facilitate quick search and application in subsequent measurements.

[0037] In one achievable manner, an anti-reflection film is plated on the incident surface of the quartz glass, and the anti-reflection film can reduce reflection loss, thereby improving the sensitivity of the measurement.

[0038] In one possible implementation, the cross section of the quartz glass is a wedge-shaped surface. The design of the wedge-shaped cross section helps to separate artifacts and avoid the generation of interference fringes, thereby improving the accuracy of measurement.

[0039] In one achievable manner, the Faraday rotation of the actual deflection angle after gain is imaged, specifically: a charge coupled device image sensor equipped with a pixelated polarizer is used to image the Faraday rotation of the actual deflection angle after gain to obtain a rotation image.

[0040] That is, a CCD image sensor equipped with a pixelated polarizer is placed behind the quartz glass. The pixelated polarizer is a special filter, each pixel has a different polarization direction, so it can record different polarization components of light at the same time, allowing the CCD image sensor to capture the detailed deflection information of the Faraday rotated light after passing through the quartz glass gain.

[0041] Preferably, Figure 2 As shown, the super pixel unit 15 is composed of four pixels with polarization directions (0°, 45°, 90°, 135°) relative to the polarizer, namely, 90° polarizer 11, 45° polarizer 12, 135° polarizer 13 and 0° polarizer 14. In the CCD image sensor, each adjacent 2×2 pixel area constitutes a super pixel unit, and the state of polarization can be determined by analyzing the gray value in each super pixel.

[0042] In an implementable manner, before determining the deflection angle after gain according to the optical rotation image, the method further includes: performing bilinear interpolation on the optical rotation image to complete the spatial resolution.

[0043] Specifically, bilinear interpolation is a commonly used image scaling and resolution enhancement technology. It calculates the grayscale values ​​of new pixels through linear interpolation based on the grayscale values ​​of adjacent pixels in the image, thereby completing the spatial resolution of the image and improving the details and clarity of the image.

[0044] In an implementable manner, determining the deflection angle after gain according to the optical rotation image is specifically: determining the polarization state by analyzing the pixel grayscale value of the optical rotation image, thereby obtaining the Faraday optical rotation deflection angle distribution.

[0045] The Faraday rotation angle measurement of the present invention is realized based on the following theoretical basis: The Faraday rotation effect refers to the phenomenon that the polarization direction of plane polarized light rotates when it passes through a plasma medium (magneto-optical medium) in the presence of a magnetic field. The formula is as follows:

[0046] in is the wavelength of the probe light, L is the path of the probe light beam through the plasma medium, B is the magnetic field along the direction of the probe light, and n e is the electron density. Therefore, by measuring the Faraday rotation angle distribution, the internal parameter distribution of the plasma can be determined.

[0047] For small-angle Faraday rotation, it can be detected by a focal plane polarimeter. The pixelated polarimeter array consists of four polarizers with directions (0°, 45°, 90°, 135°) relative to the P direction. Each adjacent 2X2 pixel area constitutes a super-pixel unit. The state of polarization can be determined by analyzing the Stokes component of light in the super-pixel unit. The specific formula is as follows:

[0048]

[0049]

[0050] in, is the grayscale value in the superpixel unit, It represents the angle between the polarization direction of the linear polarization detection beam and the polarization direction of the 0° pixel unit. However, direct use will result in a loss of 3 / 4 of the image pixels, so bilinear interpolation is used to fill in the pixels. The specific formula is as follows:

[0051]

[0052]

[0053] The 0° interpolation grayscale value at the pixel position (2, 2) is the average grayscale value of the four adjacent diagonal pixels; the 45° interpolation grayscale value is the average grayscale value of the two adjacent vertical pixels, and the 135° interpolation grayscale value is the average grayscale value of the two adjacent horizontal pixels. Therefore, the small-angle optical rotation polarization angle incident on the camera can be represented by bilinear interpolation. However, when the optical rotation angle is less than the camera angular resolution, the reflectivity ratio between S polarization and P polarization must be adjusted through Fresnel reflection. According to the Fresnel equation, it can be obtained:

[0054]

[0055] in are the refractive indices of the two media, are the angle of incidence and the angle of refraction, respectively. is the electric field component corresponding to the polarization direction. According to the law of refraction, we can get:

[0056] Introducing sensitivity indicators for:

[0057] The relationship between sensitivity and incident angle can be derived from the above formula. When the incident angle is less than the Brewster angle, there is a half-wavelength phase difference between the s-polarized light and the p-polarized light, resulting in the reflected light rotating in the opposite direction to the Faraday rotation. When approaching the Brewster angle, the sensitivity increases. However, increasing sensitivity is not always good, and the self-luminous plasma needs to be taken into account as noise.

[0058] Combination Figure 1 As shown, an embodiment of the present invention provides a Faraday rotation deflection angle measuring device, which specifically includes: The Faraday rotation emission component is used to generate Faraday rotation.

[0059] Preferably, the Faraday rotation emission assembly comprises a beam expander 1, a half-wave plate 3, a full P polarizer 4, a vacuum chamber 5 and a magneto-optical medium 6 arranged in sequence on the laser propagation path along the laser propagation path. The laser is converted into full P polarized light after passing through the full P polarizer 4, and the full P polarized light is converted into Faraday rotation after passing through the magneto-optical medium 6 in the vacuum chamber 5. A full P polarizer is arranged on the polarized light path before the optical rotation is generated, ensuring that the generated optical rotation contains only P polarized light and no S polarized light, thereby preventing interference in the measurement result of the optical rotation deflection angle.

[0060] The quartz glass is arranged on the propagation path of the Faraday rotation light, and the incident angle of the Faraday rotation light to the quartz glass is determined. The quartz glass is used to gain the actual deflection angle of the Faraday rotation light, and the gain multiple has a corresponding relationship with the incident angle of the Faraday rotation light to the quartz glass.

[0061] The optical rotation imaging component is arranged on the propagation path of the Faraday rotation light after being reflected by the quartz glass, and is used to image the Faraday rotation light after the actual deflection angle is amplified.

[0062] Preferably, the optical rotation imaging component includes a convex lens 8 arranged on the propagation path of the Faraday rotation after being reflected by the quartz glass, and a charge coupled device image sensor 9 equipped with a pixelated polarizer arranged behind the convex lens 8.

[0063] The processing module is used to determine the deflection angle after gain according to the optical rotation image, and reversely infer the actual deflection angle of the Faraday optical rotation according to the deflection angle after gain, the incident angle of the Faraday optical rotation to the quartz glass, and the corresponding relationship between the gain multiple and the incident angle of the Faraday optical rotation to the quartz glass.

[0064] Specifically, the detection light 2 emitted by the light source is expanded by the beam expander 1, and then adjusted in strength by the half-wave plate 3 and the full P polarizer 4, and then emitted to the quartz glass 8 through the magneto-optical medium 6 in the vacuum chamber 5. The reflection ratios of different polarization directions are different, and the gain multiples of the optical rotation angle are adjusted. The charge-coupled device image sensor 9 equipped with a pixelated polarizer is used for real-time visible light imaging polarization measurement, and the Faraday optical rotation angle is doubled after the detection light passes through the magneto-optical medium. The laser pulse width is in the order of ns or less, thereby ensuring the time resolution of the measurement.

[0065] Figure 1 A Faraday rotation channel 10 is formed by quartz glass 7, a convex lens 8 and a charge-coupled device image sensor 9 equipped with a pixelated polarizer, wherein the detection light passes through the electrically rotating polarizer to adjust the laser polarization direction to full P polarization, and the Faraday rotation causes the detection light passing through the magneto-optical medium 6 to have a small amount of s polarization. If the Fresnel reflection is more reflective to s polarization, the reflected light also has a larger proportion of s polarization, that is, the Faraday rotation is amplified. The refractive index of quartz glass 7 is 1.46. When the incident angle is less than the Brewster angle, there is a half-wavelength phase difference between the s-polarized light and the p-polarized light, resulting in a rotation direction of the reflected light opposite to the Faraday rotation direction. When approaching the Brewster angle, the sensitivity increases and is imaged to the charge-coupled device image sensor 9 equipped with a pixelated polarizer through the convex lens 8.

[0066] Figure 2It is a pixelated polarization array mounted on a CCD, which can be used for real-time polarization imaging of Faraday rotation. Among them, four polarizations with different polarization directions can form a superpixel unit 15, and the angle between the polarization direction of the linear polarization detection beam and the polarization direction of the superpixel 0° pixel unit can be obtained by analyzing the grayscale values ​​of different sensors in the superpixel. The light intensity of different polarizations in the superpixel unit can be regarded as the light intensity after Stokes decomposition, which can fully represent the polarization state of the light. At the same time, bilinear interpolation is used to ensure that the spatial resolution of the Faraday rotation angle is not lost. In summary, the present invention provides a Faraday rotation deflection angle measurement device, which is separated by quartz glass and enters the Faraday rotation channel. The Faraday rotation channel uses a charge-coupled device image sensor equipped with a pixelated polarizer to detect the sample beam rotation polarization angle. The sample light beam is split by quartz glass, which makes the current optical rotation angle controllable and can be increased by more than ten times, which can solve the problem of too small optical rotation angle after passing through low-density magneto-optical media, which is common in existing optical rotation diagnosis. The charge-coupled device image sensor equipped with a pixelated polarizer adopts bilinear interpolation to improve the spatial resolution. The technical solution of the charge-coupled device image sensor equipped with a pixelated polarizer through Fresnel reflection can effectively avoid the problem of limited image registration of the charge-coupled device image sensor equipped with a pixelated polarizer. The optical system has a compact structure, simple interpretation of diagnostic data, and is easy to realize miniaturization of optical rotation diagnosis, while improving the environmental adaptability of the optical rotation diagnosis channel.

[0067] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0068] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for measuring a Faraday rotation deflection angle, characterized in that: include: Quartz glass is arranged on the propagation path of Faraday rotation light, and the incident angle of Faraday rotation light to the quartz glass is determined, and the actual deflection angle of Faraday rotation light is amplified by using the quartz glass, and the gain multiple has a corresponding relationship with the incident angle of Faraday rotation light to the quartz glass; Imaging the Faraday rotation after gain to obtain an optical rotation image; The deflection angle after gain is determined according to the optical rotation image, and the actual deflection angle of the Faraday rotation is inferred according to the deflection angle after gain, the incident angle of the Faraday rotation to the quartz glass, and the corresponding relationship between the gain multiple and the incident angle of the Faraday rotation to the quartz glass.

2. The method for measuring the Faraday rotation angle according to claim 1, characterized in that: When the quartz glass is arranged, the incident angle of the Faraday rotation light onto the quartz glass is 52° to 54°.

3. The method for measuring the Faraday rotation deflection angle according to claim 1, characterized in that: The corresponding relationship between the gain factor and the incident angle of the Faraday rotation light onto the quartz glass is determined by the following method: a. deflecting all P polarized light at a known angle to obtain simulated optical rotation, wherein the deflection angle of the simulated optical rotation is the known angle; b. directing the simulated optical rotation toward the quartz glass, determining the incident angle of the simulated optical rotation toward the quartz glass, and using the quartz glass to gain the deflection angle of the simulated optical rotation; c. imaging the simulated optical rotation after gain to obtain a simulated optical rotation image; d. determining the deflection angle of the simulated optical rotation after gain according to the simulated optical rotation image; e. Determine the relationship between the incident angle of the simulated optical rotation directed to the quartz glass and the gain multiple based on the known angle and the deflection angle of the simulated optical rotation after gain; f. For different incident angles, repeat steps b to e to obtain a series of relationships between the incident angles of the simulated optical rotation incident on the quartz glass and the corresponding gain multiples, that is, the corresponding relationship between the gain multiple and the incident angle of the Faraday optical rotation incident on the quartz glass is obtained.

4. The method for measuring the Faraday rotation angle according to claim 1, characterized in that: An anti-reflection film is plated on the incident surface of the quartz glass.

5. The method for measuring the Faraday rotation deflection angle according to claim 1, characterized in that: The cross section of the quartz glass is a wedge-shaped surface.

6. The method for measuring the Faraday rotation angle according to claim 1, characterized in that: The imaging of the Faraday rotation light after the actual deflection angle is subjected to gain is specifically as follows: A charge-coupled device image sensor equipped with a pixelated polarizer is used to image the Faraday rotation of the actual deflection angle after gain to obtain a rotation image.

7. The method for measuring the Faraday rotation angle according to claim 1, characterized in that: Before determining the deflection angle after gain according to the optical rotation image, it also includes: Bilinear interpolation is performed on the optical rotation image to complete the spatial resolution.

8. The method for measuring the Faraday rotation angle according to claim 1, characterized in that: The deflection angle after gain is determined according to the optical rotation image, specifically: The polarization state is determined by analyzing the pixel grayscale value of the optical rotation image, thereby obtaining the Faraday optical rotation deflection angle distribution.

9. A Faraday rotation deflection angle measuring device, characterized in that: include: A Faraday rotation emission component, used for generating Faraday rotation; Quartz glass is arranged on the propagation path of Faraday rotation light, and the incident angle of Faraday rotation light to the quartz glass is determined. The quartz glass is used to gain the actual deflection angle of Faraday rotation light, and the gain multiple has a corresponding relationship with the incident angle of Faraday rotation light to the quartz glass; An optical rotation imaging component is arranged on the propagation path of the Faraday rotation light after being reflected by the quartz glass, and is used to image the Faraday rotation light after the actual deflection angle is amplified; The processing module is used to determine the deflection angle after gain according to the optical rotation image, and reversely infer the actual deflection angle of the Faraday optical rotation according to the deflection angle after gain, the incident angle of the Faraday optical rotation to the quartz glass, and the corresponding relationship between the gain multiple and the incident angle of the Faraday optical rotation to the quartz glass.

10. The Faraday rotation deflection angle measuring device according to claim 9, characterized in that: The Faraday rotation light emitting assembly comprises a beam expander (1), a half-wave plate (3), a full P polarizer (4), a vacuum chamber (5), and a magneto-optical medium (6) arranged in sequence on the laser propagation path along the laser propagation path; the laser light is converted into full P polarized light after passing through the full P polarizer (4); and the full P polarized light is converted into Faraday rotation light after passing through the magneto-optical medium (6) in the vacuum chamber (5); The optical rotation imaging component comprises a convex lens (8) arranged on the propagation path of the Faraday rotation light after being reflected by the quartz glass, and a charge coupled device image sensor (9) equipped with a pixelated polarizer and arranged behind the convex lens (8).

Images