Generation device and method of vector distortion Hermitian correlation light beam
Through the loading of optical devices and phase sequence diagrams, vector twisted Hermigaussian associated beams with high turbulence resistance are generated, solving the problem of difficulty in integrating multi-degree of freedom regulation in the prior art, and realizing the stability and measurement functions of the beam.
Patent Information
- Application Number
- CN202510868649.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-26
- Publication Date
- 2025-08-08
AI Technical Summary
The prior art is difficult to efficiently integrate vector polarization, distorted phase and special correlation characteristics into a single beam, achieving flexible regulation and measurement of multiple degrees of freedom.
Using an optical device including a first beam splitter, a spatial light modulator, a lens and a radial polarization conversion sheet, a vector twisted Hermigaussian associated beam is generated by loading a preset phase sequence diagram into the spatial light modulator, and a CCD camera is used to measure the Stokes parameter of the beam.
It realizes the generation of stable and accurate vector-distorted Hermigaussian associated beams, has high turbulence resistance, is suitable for free space optical communication, and can simultaneously measure the polarization state of the beam.
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Figure CN120447217A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of optical technology, and in particular to a device and method for generating a vector-distorted Hermite-Gaussian correlation light beam. Background Art
[0002] Partially coherent light (i.e., a laser beam with reduced coherence) offers advantages in many fields, including photolithography, quantitative imaging, ghost imaging, remote detection, light scattering, particle trapping, and free-space optical communications. Furthermore, by constructing special spatially coherent structures in the light field, partially coherent light exhibits unique transmission properties, such as self-shaping, self-splitting, and self-reconstruction.
[0003] In addition, polarization, as another important degree of freedom in light field manipulation, gives the light field many new physical properties, such as being able to effectively improve the light beam's ability to resist turbulence. Studies have shown that partially coherent light beams with twisted phases have orbital angular momentum, which has a more obvious advantage in improving the light beam's resistance to disturbances in complex environments and can give the light beam more dimensional control capabilities. Therefore, vector-specific correlated light beams carrying twisted phases (multi-degree-of-freedom joint manipulation) will have more important advantages in resisting the negative effects of turbulence and improving signal stability, and will have important applications in optical information encryption, super-resolution imaging, and free-space optical communications.
[0004] However, the generation of specially correlated twisted beams is currently limited to scalar applications. Efficiently integrating properties such as vector polarization, twisted phase, and special correlation into a single beam, while enabling flexible control, generation, and measurement of multiple degrees of freedom, remains a pressing challenge. Summary of the Invention
[0005] The present invention aims to provide a device and method for generating a vector twisted Hermite-Gaussian correlation beam, so as to solve the problem of how to efficiently integrate characteristics such as vector polarization, twisted phase, and special correlation into a single beam.
[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical solution: a device for generating a vector-distorted Hermite-Gaussian correlated light beam, comprising: a first beam splitter, a spatial light modulator, a light source branch and a reflection branch; the reflection branch comprises a first lens, an aperture, a second lens and a radial polarization converter arranged in sequence, the center of the first lens, the center of the second lens and the center of the radial polarization converter are collinear with the reflection point of the first beam splitter; the light source branch is used to generate a light beam and is incident on the first beam splitter; the spatial light modulator is used to modulate the transmitted light of the first beam splitter and reflect it to the first beam splitter, and the first beam splitter reflects the reflected light beam of the spatial light modulator to the reflection branch to obtain a vector-distorted Hermite-Gaussian correlated light beam; when a preset phase sequence diagram is loaded into the spatial light modulator, at any z plane The light intensity at a point is:
[0007]
[0008] Where N is the number of pseudo patterns, sampled in the interval |v|≤2a, and the sampling interval is Δv=2a / 7.
[0009] It is further defined that the light source branch includes: a light source, an attenuation plate and a beam expander, and the output port of the light source, the output port of the attenuation plate and the output port of the beam expander are collinear with the incident light port of the first beam splitter.
[0010] After the laser beam is intensity-adjusted by an attenuation plate, it is incident on a beam expander for beam expansion, and then incident on the first beam splitter for beam splitting. The transmitted light is incident on a spatial light modulator loaded with a computer-generated hologram. The light beam modulated by the spatial light modulator is reflected back to the first beam splitter, reflected by the first beam splitter, and passes through the first lens. The first lens converges the light beam onto the aperture to select a first-order diffraction spot, and then passes through the second lens and a radial polarization converter to obtain a vector-distorted Hermite-Gaussian correlated light beam.
[0011] It is further defined that the light source is a laser.
[0012] It is further defined that the light spot after expansion by the beam expander can cover the hologram on the spatial light modulator.
[0013] It is further defined that the first lens and the second lens constitute a 4f optical system.
[0014] It is further defined that the spatial light modulator is connected to a computer terminal, and the spatial light modulator adopts a phase grating designed by computer holography.
[0015] It is further defined that the computer terminal generates a preset number of holograms distributed with a preset probability, and the spatial light modulator plays the holograms at a certain frequency.
[0016] The invention further includes a second beam splitter, a fourth lens, and a third CCD camera. The second beam splitter is configured to split the vector-distorted Hermite-Gaussian correlation beam generated by the radial polarization converter and transmit the reflected beam to the fourth lens. The reflected light sequentially passes through the fourth lens and the third CCD camera. This branch is used to measure the transmission evolution characteristics of the vector-distorted Hermite-Gaussian correlation beam.
[0017] To achieve the above object, the present invention further provides a method for generating a vector-distorted Hermite-Gaussian correlation beam, comprising:
[0018] A light source branch, a first beam splitter, a spatial light modulator, a first lens, an aperture, a second lens, and a radial polarization converter are sequentially arranged along the optical path.
[0019] According to the preset number of patterns and the number of holograms, the weight of each pattern is determined according to a preset weight function; according to the weight of each pattern, all holograms are loaded onto the spatial light modulator for cyclic playback;
[0020] A vector-distorted Hermite-Gaussian correlated beam is obtained at the output port of the radial polarization converter.
[0021] According to the above method, a stable and accurate vector twisted Hermite-Gaussian correlated beam is obtained. The generation method is simple. The beam simultaneously integrates characteristics such as vector polarization, twisted phase, and special correlation structure. It has high anti-turbulence ability and is a good carrier for free-space optical communication.
[0022] It is further defined that the hologram is loaded onto the spatial light modulator in the form of a random animation sequence, and the probability of each pattern appearing is determined by a weight function.
[0023] To achieve the above-mentioned objectives, the present invention also provides a device for measuring the Stokes parameters of a vector-distorted Hermite-Gaussian correlated beam, which is arranged at the exit end of the radial polarization converter of the above-mentioned vector-distorted Hermite-Gaussian correlated beam generating device, and includes: a second beam splitter, a third lens, a third beam splitter, a vertical measurement branch and a horizontal measurement branch, wherein the horizontal measurement branch includes a first quarter-wave plate, a first linear polarizer and a first CCD camera arranged in sequence; the vertical measurement branch includes a second quarter-wave plate, a second linear polarizer and a second CCD camera; the reflection point of the second beam splitter, the center point of the third lens and the incident light port of the third beam splitter are collinear; the second beam splitter is used to split the vector-distorted Hermite-Gaussian correlated beam generated at the radial polarization converter, and the transmitted beam is incident on the third lens; the third beam splitter is used to split the beam into two beams and enter the first quarter-wave plate and the second quarter-wave plate respectively, the transmission direction of the first linear polarizer is adjustable, and the transmission direction of the second linear polarizer is also adjustable.
[0024] It is further defined that the distance from the third lens to the second beam splitter, the distance from the third lens to the first CCD camera, and the distance from the third lens to the second CCD camera are all 2f.
[0025] It is further defined that the first CCD camera and the second CCD camera operate in a synchronous mode and are controlled by a digital signal generator to simultaneously capture light intensity components in two different directions.
[0026] To achieve the above object, the present invention further provides a method for measuring the Stokes parameters of a vector-distorted Hermite-Gaussian correlation beam, comprising:
[0027] Splitting the vector-distorted Hermite-Gaussian correlation beam generated at the radial polarization converter into two beams through a second beam splitter;
[0028] The light beam in the transmission branch is also split into two beams after passing through the third beam splitter, one beam passes through the first linear polarizer, and the other beam passes through the second linear polarizer;
[0029] The first CCD camera is used to obtain the light intensity in the horizontal direction, and the second CCD camera is used to obtain the light intensity in the vertical direction. The Stokes parameter S0 is obtained by adding the light intensity in the horizontal direction and the light intensity in the vertical direction, and the Stokes parameter S1 is obtained by subtracting the light intensity in the horizontal direction from the vertical direction.
[0030] The first linear polarizer is rotated so that its transmission direction is 45° to the horizontal direction to obtain the transmitted light intensity in this direction. The second linear polarizer is rotated so that its transmission direction is 135° to the horizontal direction to obtain the transmitted light intensity in this direction. The Stokes parameter S2 is obtained by subtracting the light intensity in the 135° direction from the light intensity in the 45° direction.
[0031] A quarter-wave plate is placed before each of the first and second linear polarizers. The vector-distorted Hermite-Gaussian correlated beams from the third beam splitter are sequentially passed through a quarter-wave plate and a linear polarizer. The fast axis of the quarter-wave plate is set horizontally and fixed. The first linear polarizer's transmission direction is ensured to be 45° to the horizontal, and the transmitted light intensity in this direction is measured using a first CCD camera. The second linear polarizer's transmission direction is ensured to be 135° to the horizontal, and the transmitted light intensity in this direction is measured using a second CCD camera. The Stokes parameter S3 is obtained by subtracting the second from the first.
[0032] In this scheme, the generated vector twisted Hermite-Gaussian correlation beam is split into two beams through a second beam splitter, wherein the transmission branch is used to measure the Stokes parameter of the beam light source surface.
[0033] S0 is the total light intensity, S1 is the difference between horizontal and vertical polarization components, S2 is the difference between diagonal polarization components, and S3 is the difference between left and right circular polarization components. The optical elements required to measure different Stokes parameters are not exactly the same. Sometimes only a linear polarizer is needed, such as measuring S0, S1, and S2. Sometimes both a quarter-wave plate and a linear polarizer are needed, such as measuring S3.
[0034] The beneficial effects of the present invention are:
[0035] 1. This scheme obtains a stable and accurate vector-distorted Hermite-Gaussian correlated beam by loading the phase sequence diagram into the spatial light modulator in the form of a random animation. This beam simultaneously integrates the characteristics of vector polarization, twisted phase, and special correlation structure, has high anti-turbulence ability, and is an excellent carrier for free-space optical communication. In addition, the generation method is simple and the generation device is concise.
[0036] 2. In addition to generating a vector-distorted Hermite-Gaussian correlated beam, this scheme can also simultaneously measure the Stokes parameters of the beam, thereby obtaining the polarization state of the beam. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 Schematic diagram of the structure of an embodiment of the present invention.
[0038] Figure 2 This is a transmission evolution characteristic diagram of a vector-distorted Hermite-Gaussian correlated beam according to an embodiment of the present invention.
[0039] Figure 3 This is a diagram showing the measurement results of the Stokes parameters and polarization degree of a vector-twisted Hermite-Gaussian correlated beam according to an embodiment of the present invention. DETAILED DESCRIPTION
[0040] The following is further described in detail through specific implementation methods:
[0041] The figure marks in the drawings of the specification include: laser 1, attenuation plate 2, beam expander 3, first beam splitter 4, spatial light modulator 5, first thin lens 6, aperture 7, second thin lens 8, radial polarization converter 9, second beam splitter 10, third lens 11, third beam splitter 12, first quarter wave plate 13, first linear polarizer 14, first CCD camera 15, second quarter wave plate 16, second linear polarizer 17, second CCD camera 18, fourth lens 19, third CCD camera 20.
[0042] Example:
[0043] A device for generating vector distorted Hermite-Gaussian correlation beams is shown in the attached figure. Figure 1 As shown, it includes a laser light source 1 with a preset optical path setting, an attenuation plate 2, a beam expander 3, a first beam splitter 4, a spatial light modulator 5, a first lens 6, an aperture 7, a second lens 8 and a radial polarization converter 9.
[0044] The laser light source is a laser 1. The first lens and the second lens are both thin lenses.
[0045] The working method of the above-mentioned device is as follows: a monochromatic laser beam coming out of the laser 1 passes through the attenuation plate 2 (ND) to adjust the light intensity distribution, then passes through a beam expander 3 (BE) for beam expansion, and then passes through the first beam splitter 4 (BS) for beam splitting. The transmitted light then passes through a reflective spatial light modulator 5 (SLM), and the SLM is loaded with a computer-generated hologram by a computer.
[0046] After the light beam reflected by the spatial light modulator 5 enters the first beam splitter 4, it is converged by the first thin lens 6 (L1) and converged onto the plane of the aperture 7 (CA3). The first-order diffraction spot is selected by the aperture 7. After passing through the second thin lens 8 (L2) and the radial polarization converter (RPC), a vector-distorted Hermite-Gaussian correlated beam is generated.
[0047] This solution also provides a method for generating a vector-distorted Hermite-Gaussian correlation beam based on the above-mentioned device, comprising:
[0048] determining a weight for each mode according to a preset number of modes and number of holograms and a preset weight function;
[0049] According to the weight of each mode, all holograms are loaded onto the spatial light modulator 5 and played in a loop;
[0050] The hologram is loaded onto the spatial light modulator 5 in the form of a random animation sequence, and the probability of each pattern appearing is determined by a weight function.
[0051] Each hologram represents a pattern, and holograms representing different patterns are played cyclically on the spatial light modulator 5 according to a preset probability, and each hologram has the same play time.
[0052] Specifically include the following:
[0053] First, a vector twisted Hermite-Gaussian correlated beam is constructed. In the spatial frequency domain, the vector partially coherent beam is characterized by the cross spectral density matrix.
[0054]
[0055] Among them, W αβ (r1, r2)(α, β=x, y) is the cross spectral density matrix element, r1, r2 are two arbitrary position vectors on the transverse plane of the light source.
[0056] If such a beam can be generated physically, then each element of its cross-spectral density matrix must satisfy the non-negative positive definite condition,
[0057]
[0058] Among them, α and β represent the two components of x and y, p(v) is a non-negative weight matrix function, v is an arbitrary position vector in the spatial frequency domain, and H α(β) (r2,v) is an arbitrary kernel function, p αβ (v) is the matrix element of the weight matrix p(v), and the weight matrix and the matrix element satisfy:
[0059]
[0060] p xx (v)≥0,p yy (v)≥0,p xx (v)p yy (v)≥|p xy (v)| 2 , (4)
[0061] H α(β) (r,v) is an arbitrary kernel function.
[0062] When p αβ (v) and H α(β) Different forms of (r2,v) are selected, and different types of vector partially coherent beams are generated. In this embodiment, in order to generate a vector twisted Hermite-Gaussian correlation beam, p αβ (v) and H α(β) (r2,v) are respectively in the following forms, which can generate radially polarized distorted Hermite-Gaussian correlated beams.
[0063] p αβ (v)=B αβ (1 / 4π)(4a) 2m+1 (v x v y ) 2m exp(-av 2 ), (5)
[0064] H α(β) (r,v)=α(β)exp(-σr 2 )exp{-[(auy+ix)v x -(aux-iy)v y ]}, (6)
[0065] Among them, B αβ is the correlation coefficient, and B xx =B yy =1, B xy =B yx =1, σ is a positive real constant representing the width of the kernel function, a is a positive real constant determining the coherence width, u is a real constant representing the distortion factor, i is the imaginary unit, and m is a positive integer representing the beam order.
[0066] Substituting equations (5) and (6) into equation (2), we can obtain the cross spectral density matrix (7) of the radially polarized twisted Hermite-Gaussian correlated beam.
[0067]
[0068] Where ω0 represents the beam spot width parameter, which satisfies ω0=(4σ-2au 2), δ0 represents the coherence width parameter of the beam, and satisfies According to the Fresnel diffraction integral, the cross spectral density matrix element of the partially coherent beam transmitted to any z plane in free space and the cross spectral density matrix element at the light source satisfy:
[0069]
[0070] Where λ is the wavelength of light, z is the transmission distance, and k is the wave number of light. For some vector partially coherent beams that are difficult to handle mathematically, It is expressed as follows:
[0071]
[0072] Based on the above analysis, in order to generate a vector Hermitian inhomogeneous correlated beam in the experiment, this embodiment discretizes the integral of v in formula (2), effectively replacing the continuous distribution of incoherent modes with a finite set. This is because it has been proven that pseudo-mode expansion can well approximate the exact integral, even with a relatively small number of modes. In discrete form, the matrix elements of the cross-spectral density matrix can be expressed as:
[0073]
[0074] in, Indicated by v n A mode is determined, and Δv represents the sampling interval.
[0075] So, in any z plane The light intensity at a point can be expressed as follows:
[0076]
[0077] Where N is the number of pseudo-patterns, sampled in the interval |v|≤2a, and the sampling interval is Δv=2a / 7. In this embodiment, 225 patterns are selected, 225 phase images are synthesized in the computer terminal, and they are loaded into the SLM in a random animation sequence, where the probability of each pseudo-pattern occurring is determined by formula (3).
[0078] The average frames per second (fps) of the phase pattern sequence loaded into the SLM was approximately 15 s-1, which is lower than the maximum SLM refresh rate of 60 Hz. The intensity of the vector-distorted Hermite-Gaussian correlation beam was then obtained by averaging the pseudo-mode image sequence captured by the CCD camera. In this example, 1200 images were used.
[0079] The system also includes a second beam splitter 10, a fourth lens 19, and a third CCD camera 20. The second beam splitter 10 is used to split the vector-distorted Hermite-Gaussian correlation beam generated by the radial polarization converter 9 and transmit the reflected beam to the fourth lens 19. The reflected light passes through the fourth lens 19 and the third CCD camera 20 in sequence. This branch is used to measure the transmission evolution characteristics of the vector-distorted Hermite-Gaussian correlation beam. Figure 2 The transmission evolution characteristics of the beam are given. Figure 2 In the figure, the beam order m and distortion factor u corresponding to the three rows from top to bottom are m = 1, u = 1, m = 1, u = 2, and m = 2, u = 2, respectively. The corresponding columns show the light intensity distribution characteristics at the light source surface, 0.2 focal length, 0.4 focal length, 0.6 focal length, 0.8 focal length, and one focal length respectively.
[0080] This solution also provides a device for measuring the Stokes parameters of a vector-distorted Hermite-Gaussian correlation beam based on the above device, as shown in the attached figure. Figure 1 As shown, on the basis of the above device, a second beam splitter 10, a third lens 11, a third beam splitter 12, a first quarter wave plate 13, a first linear polarizer 14, a first CCD camera 15, a second quarter wave plate 16, a second linear polarizer 17 and a second CCD camera 18 are also provided.
[0081] The first CCD camera 15 and the second CCD camera 18 operate in a synchronous mode and are controlled by a digital signal generator to simultaneously capture two different light intensity components.
[0082] When measuring the Stokes parameters S0, S1 and S2, the first quarter wave plate 13 and the second quarter wave plate 16 do not need to be placed. When measuring the Stokes parameter S3, these two quarter wave plates need to be placed.
[0083] This solution also provides a measurement method based on the above-mentioned measurement device, including:
[0084] In theory, the calculation of Stokes parameters is mainly based on the relationship between them and the cross-spectral density matrix:
[0085] S0(ρ,z)=W xx (ρ,z)+W yy (ρ,z), (14)
[0086] S1(ρ,z)=W xx (ρ,z)-W yy (ρ,z), (15)
[0087] S2(ρ,z)=W xy (ρ,z)+W yx (ρ,z), (16)
[0088] S3(ρ,z)=i[W yx (ρ,z)-W xy (ρ,z)], (17)
[0089] In the experiment, the Stokes parameters were obtained mainly by measuring six different sets of light intensities. The generated vector distorted Hermite-Gaussian correlation beam passed through the third beam splitter 12 and then through the first linear polarizer 14 and the second linear polarizer 17. The transmission directions of the two polarizers were set in the horizontal and vertical directions respectively. The measured transmitted light intensities were recorded as I 0° and I 90° The sum of the two is S0, and the difference between the two is S1.
[0090] Then the two linear polarizers are placed at 45° and 135° to the horizontal direction, and the intensity of the transmitted light is measured. 45° and I 135° , thus S2 is:
[0091] S2(ρ,z)=I 45° (ρ,z)-I 135° (ρ,z). (18)
[0092] The generated vector distorted Hermite-Gaussian correlation beam passes through the third beam splitter 12, and then passes through a quarter wave plate and a linear polarizer in sequence, with the fast axis direction of the wave plate along the horizontal direction. Then, the first linear polarizer 14 and the second linear polarizer 17 are placed at 45° and 135° to the horizontal direction respectively, and the first CCD camera 15 and the second CCD camera 18 are used to obtain the light intensity distribution I under the two conditions respectively. 右旋 and I 左旋 , thus S3 is:
[0093] S3(ρ,z)=I 右旋 -I 左旋 , (19)
[0094] Figure 3 Figure 3. Stokes parameters and polarization degree distributions of radially polarized twisted Hermite-Gaussian correlated beams measured using this experimental setup. The first three rows, from top to bottom, correspond to beam order m and twist factor u, respectively: m = 1, u = 1, m = 1, u = 2, and m = 2, u = 2. From left to right, they show S0, S1, S2, S3, and the polarization degree distribution.
[0095] The above embodiments provide a method for generating, a method for measuring, and a device for generating a vector-distorted Hermite-Gaussian correlated light beam, which can be realized. The device is flexible and concise and has broad application prospects.
[0096] The above description is merely an embodiment of the present invention, and the commonly known specific technical solutions and / or features of the solution are not described in detail here. It should be noted that those skilled in the art can make a number of modifications and improvements without departing from the technical solution of the present invention. In the present invention, unless otherwise clearly specified or limited, the scope of protection claimed by this application shall be based on the content of the claims, and the specific implementation methods and other records in the specification may be used to interpret the content of the claims.
Claims
1. A device for generating a vector-distorted Hermite-Gaussian correlation beam, characterized in that: include: a first beam splitter, a spatial light modulator, a light source branch, and a reflection branch; The reflection branch comprises a first lens, an aperture, a second lens and a radial polarization converter arranged in sequence, wherein the center of the first lens, the center of the second lens and the center of the radial polarization converter are collinear with the reflection point of the first beam splitter; The light source branch is used to generate a light beam and is incident on the first beam splitter; the spatial light modulator is used to modulate the transmitted light of the first beam splitter and reflect it to the first beam splitter, and the first beam splitter reflects the reflected light beam of the spatial light modulator to the reflection branch to obtain a vector distorted Hermite-Gaussian correlated light beam.
2. The device for generating a vector-distorted Hermite-Gaussian correlation beam according to claim 1, characterized in that: The light source branch includes: a light source, an attenuation plate and a beam expander. The exit port of the light source, the exit port of the attenuation plate and the exit port of the beam expander are collinear with the incident light port of the first beam splitter.
3. The device according to claim 2, characterized in that: The light source is a laser.
4. The device according to claim 2, characterized in that: The light spot expanded by the beam expander can cover the hologram on the spatial light modulator.
5. The device according to claim 2, characterized in that: The first lens and the second lens constitute a 4f optical system.
6. The device according to claim 1, characterized in that: The spatial light modulator is connected to a computer terminal, and the spatial light modulator adopts a phase grating designed by computer holography.
7. A method for generating a vector-distorted Hermite-Gaussian correlation beam based on the device of claim 1, characterized in that: A light source branch, a first beam splitter, a spatial light modulator, a first lens, an aperture, a second lens, and a radial polarization converter are sequentially arranged along the optical path direction; Determining the weight of each mode according to a preset number of modes and a preset number of holograms, and a preset weight function; According to the weight of each pattern, all holograms are loaded onto the spatial light modulator and played in a loop; A vector-distorted Hermite-Gaussian correlated beam is obtained at the output port of the radial polarization converter.
8. The method according to claim 7, wherein: The hologram is loaded onto the spatial light modulator in the form of a random animation sequence, and the probability of each pattern appearing is determined by a weight function.
9. A device for measuring the Stokes parameters of a vector-distorted Hermite-Gaussian correlation beam based on the device of claim 1, characterized in that: Also includes: a second beam splitter, a third lens, a third beam splitter, a vertical measurement branch, and a horizontal measurement branch; The horizontal measurement branch includes a first quarter-wave plate, a first linear polarizer and a first CCD camera arranged in sequence; the vertical measurement branch includes a second quarter-wave plate, a second linear polarizer and a second CCD camera; the transmission point of the second beam splitter, the center point of the third lens and the incident light port of the third beam splitter are collinear; the second beam splitter is used to split the vector-distorted Hermite-Gaussian correlated light beam generated at the radial polarization converter and to input the transmitted light beam into the third lens; the third beam splitter is used to split the light beam into two beams and enter the first quarter-wave plate and the second quarter-wave plate respectively, and the transmission directions of the first linear polarizer and the second linear polarizer are adjustable.
10. A method for measuring the Stokes parameters of a vector-distorted Hermite-Gaussian correlation beam based on the device of claim 9, characterized in that: include: The vector-distorted Hermite-Gaussian correlated beam generated at the radial polarization converter is split into two beams by a second beam splitter; the beam in the transmission branch is also split into two beams after passing through a third beam splitter, one beam passing through the first linear polarizer and the other beam passing through the second linear polarizer; Adjust the transmission direction of the linear polarizer so that the first CCD camera can obtain the horizontal light intensity distribution, and the second CCD camera can obtain the vertical light intensity distribution. The Stokes parameter S0 is obtained by adding the horizontal and vertical light intensities, and the Stokes parameter S1 is obtained by subtracting the horizontal and vertical light intensities. The first linear polarizer is rotated so that its transmission direction is 45° to the horizontal direction to obtain the transmitted light intensity in this direction. The second linear polarizer is rotated so that its transmission direction is 135° to the horizontal direction to obtain the transmitted light intensity in this direction. The Stokes parameter S2 is obtained by subtracting the light intensity in the 135° direction from the light intensity in the 45° direction. A quarter-wave plate is added before the first linear polarizer and the second linear polarizer, respectively. The vector-distorted Hermite-Gauss correlated light beam coming out of the third beam splitter passes through a quarter-wave plate and a linear polarizer in sequence, and the fast axis direction of the quarter-wave plate is set to be horizontal and fixed; and the transmission direction of the first linear polarizer is ensured to be 45° to the horizontal direction, and the transmitted light intensity in this direction is measured by a first CCD camera; the transmission direction of the second linear polarizer is ensured to be 135° to the horizontal direction, and the transmitted light intensity in this direction is measured by a second CCD camera. The Stokes parameter S3 can be obtained by subtracting the latter from the former.