A method and device for realizing light field vector regulation through a scattering medium

Abstract

The application belongs to the field of optical information processing, and discloses a method and device for realizing light field vector regulation through a scattering medium, which is used for solving the poor real-time performance and the limitation of being unable to regulate the light field of a traditional wavefront shaping method. 1 The orthogonal component E 1 SH of the complex amplitude of the speckle field through the scattering medium 1 SV The orthogonal component E 2 The orthogonal component E 2 SH of the complex amplitude of the speckle field through the scattering medium 2 SV According to the digital optical phase conjugation technology and the light field regulation theory, the four complex amplitude components are simultaneously conjugated and returned and phase and amplitude regulation is applied, so that the focusing and vector regulation of the light field can be realized. The method can realize the real-time focusing and polarization state regulation of the light beam through the scattering medium, and is beneficial to the application of the vector light field in the imaging field of the scattering medium.

Description

Technical Field

[0001] This invention relates to a vector wavefront shaping method, specifically a method for achieving vector control of the optical field through a scattering medium. Background Technology

[0002] Wavefront shaping is a technique that utilizes spatial light modulators to pixel-level control the complex amplitude of a light wavefront, enabling the modulated light wave to be focused or imaged without distortion after passing through a scattering medium. Essentially, it compensates for wavefront distortion caused by the scattering medium by pre-modulating the complex amplitude of the wavefront, allowing the light to be refocused or imaged after passing through the scattering medium. The aim of this technique is to achieve clear imaging of light beams through scattering media such as deep biological tissues, turbid liquids, and atmospheric turbulence. Based on different implementation methods, existing wavefront shaping techniques can be divided into three main categories: iterative optimization techniques, transfer matrix techniques, and optical phase conjugation techniques. Iterative optimization and transfer matrix techniques require multiple acquisitions of speckle distributions, making real-time shaping difficult. Optical phase conjugation techniques, based on the time-reversal principle, require only a single acquisition to achieve real-time wavefront shaping, making them superior for wavefront shaping in dynamic scattering media. While existing wavefront shaping techniques can achieve focusing or imaging of light fields through scattering media, they struggle to achieve polarization control of the light field, thus failing to meet the requirements for applications such as polarized molecular imaging or vector focusing through scattering media. Summary of the Invention

[0003] The purpose of this invention is to provide a method and apparatus for controlling the vector of the light field through a scattering medium, overcoming the shortcomings of existing wavefront shaping techniques that are difficult to control the polarization distribution of the light field, and providing a new technical means for the imaging theory of scattering media. The main principle is based on digital optical phase conjugation and vector synthesis and decomposition of light waves.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0005] On the one hand, a method for controlling the optical field vector through a scattering medium is characterized by comprising the following steps:

[0006] S1, Speckle Field Complex Amplitude Recording Process: Based on off-axis digital holography and polarization angle multiplexing technology, left-handed circularly polarized light and right-handed circularly polarized light are sequentially passed through the scattering medium to form speckle fields S1 and S2, which then undergo compound interference with horizontally polarized reference light and vertically polarized reference light to form compound holograms H1(m,n) and H2(m,n), where (m,n) are discretized pixel coordinates;

[0007] S2. Process of obtaining the conjugate phase of the speckle field: The orthogonal polarization components of the complex amplitude of the speckle field formed by left-handed and right-handed circularly polarized light are demodulated from the composite holograms H1(m,n) and H2(m,n) using numerical reconstruction methods, and the conjugate phase distribution is further obtained by numerical calculation from the complex amplitude. Subscripts s and p represent the horizontal and vertical polarization components of the complex amplitude of the speckle field, respectively;

[0008] S3, Speckle Field Phase Conjugation and Refocusing Process: [The process involves...] and The image is converted to the image corresponding to the spatial light modulation device, and then encoded into the same grayscale image G1(m,n). Similarly, the image is converted to the image corresponding to the spatial light modulation device. and Encode them into the same image G2(m,n); load G1 and G2 onto two spatial light modulation devices simultaneously, and illuminate them with a reference light to obtain two phase conjugate beams. Use image acquisition device 2 to record the complex amplitude and polarization distribution of the superimposed focal point formed by the two phase conjugate beams.

[0009] S4. Phase conjugate beam vector modulation process: Different phase differences are applied to the conjugate phase distribution obtained in step S2, and the intensity ratio of the two reference beams is changed. According to the principle of vector beam synthesis and decomposition, the phase conjugate beam at this time is formed by the superposition of left-handed and right-handed circularly polarized light, and the intensity and phase of the left-handed and right-handed circularly polarized light are adjustable. The focal polarization distribution formed by the conjugate beam is recorded by the detection image acquisition device, thus completing the vector modulation of the beam through the scattering medium.

[0010] Preferably, the speckle field complex amplitude recording process corresponds to Figure 2 The optical path structure shown includes the following steps:

[0011] (S1-1) The visible light output from the continuous laser source 1 is converted into a linearly polarized beam after passing through the optical beam expander collimation system 2, and then modulated by the polarizer 3 to obtain a 45-degree linearly polarized beam, which is then split into a transmitted beam and a reflected beam by the polarizing beam splitter 4.

[0012] (S1-2) The reflected beam is modulated by the polarization modulation system 5 to obtain a left-hand circularly polarized beam, which passes through the reflector 6 and the converging lens 7 in sequence and is incident into the scattering medium 8. The scattered beam exiting from the scattering medium is collected by the converging lens 9, and after passing through the non-polarizing beam combiner 10, it reaches the target surface of the image acquisition device 11 to form a speckle field, denoted as S1.

[0013] (S1-3) The transmitted beam passes again through the unpolarized beam splitter 12 and the half-wave plate 13, splitting into horizontally polarized light R. 1S and vertically polarized light R 1PThe light beam is incident perpendicularly onto the surfaces of two reflective spatial light modulators 14 and 15, respectively. The polarization response direction of the spatial light modulator is consistent with the polarization direction of the light beam, and the light beam is in the off state.

[0014] (S1-4) After the two beams of light are directly reflected by the spatial light modulator, they are combined again by the non-polarizing beam splitter and then reach the target surface of the image acquisition device after passing through the 4f system composed of lens 16 and lens 17. The spatial position, pitch and rotation angles of the two reflective spatial light modulators and the image acquisition device are adjusted so that the two reflective spatial light modulators and the image acquisition device are in the conjugate plane of the 4f system.

[0015] (S1-5) Fine-tune the angle of the depolarizing beam combiner in front of the image acquisition device so that S1 and R S R P Off-axis interference occurs, forming a composite hologram H1(m,n), which is recorded by the imaging device; then, the left-handed circularly polarized light is adjusted to right-handed circularly polarized light, resulting in the speckle field S2 and the reference light R. S R P The off-axis interference again forms a composite hologram H2(m,n), which is recorded by the image acquisition device.

[0016] Preferably, the method used for obtaining the conjugate phase of the speckle field in the digital holographic complex amplitude reconstruction is the angular spectrum method.

[0017] Preferably, the speckle field phase conjugation and refocusing process corresponds to Figure 3 Specifically, it includes the following steps:

[0018] (S3-1) Conjugate phase and Converted into grayscale images G of spatial light modulators respectively 1S (m,n) and G 2S (m,n), using the pixel space reuse method, G 1S (m,n) and G 2S (m,n), fused and encoded into a grayscale image G1, similarly based on the conjugate phase. and The resulting fused coded grayscale image G2 is obtained, and the fusion coding method is as follows: Figure 4 As shown;

[0019] (S3-2) Load G1 and G2 onto two spatial light modulators respectively, and use the two reference beams separated in step S1 to illuminate the two spatial light modulators respectively.

[0020] (S3-3) Place a reflector 18 in the transmission direction of the non-polarizing beam splitter 10 in front of the image acquisition device, and adjust the spatial position, pitch and rotation angle of the reflector so that the reflector is also in the conjugate plane of the 4f system in step S1. At this time, the reflector and the target surface of the image acquisition device are symmetrical and equivalent about the non-polarizing beam splitter.

[0021] (S3-4) After the two phase conjugate beams are reflected by the reflector and the depolarizing beam combiner, they are transmitted in the opposite direction and pass through the lens, the scattering medium and the lens in sequence. Then the direction of the reflector 6 is rotated to the downward direction in the figure, and the beams are focused by the lens 19 onto the target surface of the image acquisition device 2.

[0022] Preferably, the phase conjugate beam vector modulation process specifically includes the following steps:

[0023] (S4-1) Based on the principle of vector light field decomposition and synthesis, calculate the phase difference and intensity ratio of the left and right circularly polarized components corresponding to the required polarized light distribution;

[0024] (S4-2) Adjust the intensity ratio of the incident light to the two spatial light modulators until the required value is met;

[0025] (S4-3) Maintain the conjugate phase G of the left-handed circularly polarized light respectively 1S (m,n) and G 1P Phase difference of (m,n) Constant, and the conjugate phase G of right-handed circularly polarized light 2S (m,n) and G 2P Phase difference of (m,n) Keep the overall phase difference between left-handed and right-handed circularly polarized beams constant, then change the overall phase difference between them. Achieve vector control of synthesized phase-conjugated light.

[0026] On the other hand, a device for controlling the optical field vector through a scattering medium includes a laser, a beam expander and collimator, a polarizer, a half-wave plate, a polarization control system, two mirrors, a scattering medium, five lenses, a polarizing beam splitter, two unpolarizing beam splitters, two spatial light modulators, two image acquisition devices, and a computer. The light emitted from the laser passes sequentially through the beam expander and collimator and the polarizer to obtain a 45-degree linearly polarized beam. This beam is then split into two beams by the polarizing beam splitter. The reflected beam is converted to left-handed circularly polarized light by the polarization control system, reflected by the mirrors, converged by the lenses, passes through the scattering medium, is collected and collimated by the lenses, and then passes through the unpolarizing beam splitter to reach the target surface of the image acquisition device. The beam transmitted by the polarizing beam splitter is split into two beams again by the non-polarizing beam splitter. One beam is modulated by the half-wave plate and then incident on the two spatial light modulators. After being reflected, it is re-combined by the non-polarizing beam splitter and imaged onto the target surface of image acquisition device one by the 4f imaging system composed of the two lenses. It then undergoes angular multiplexing interference with the speckle field to form a hologram. During the phase conjugation and refocusing process of the speckle field, a reflector is placed symmetrically about the non-polarizing beam splitter on image acquisition device one, and the reflector in front of the scattering medium is rotated by 90 degrees. This allows the phase conjugated beam to exit from the reflector and be converged by the lens onto image acquisition device two, realizing real-time detection of the phase conjugated beam focusing effect and vector control result.

[0027] Beneficial effects

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. The method for controlling the light field vector through the scattering medium of the present invention is based on digital optical phase conjugation technology. By recording all polarization components of the complex amplitude of the speckle field and performing full polarization conjugation, the simultaneous conjugation of the polarization and phase of the speckle field is achieved, which improves the conjugation efficiency by nearly 100% compared with the prior art.

[0030] 2. The optical field vector control method of the present invention through the scattering medium utilizes two spatial light modulation devices to simultaneously conjugate the orthogonal polarization components of the speckle field complex amplitude, and adopts a pixel-level interleaved coding method and spatial multiplexing technology to significantly improve the utilization rate of the conjugate beam.

[0031] 3. The method for controlling the light field vector through the scattering medium of the present invention is based on the principle of decomposition and synthesis of vector light field. It uses a pair of orthogonal polarized light as basis vectors and combines two spatial light modulation devices and polarization optical elements to control the complex amplitude of the orthogonal polarized light, thereby realizing real-time control of the polarization state of the light field through the scattering medium. Attached Figure Description

[0032] Figure 1 This is a flowchart of the method for achieving optical field vector manipulation through a scattering medium according to the present invention.

[0033] Figure 2 This is an optical path diagram of the speckle field complex amplitude recording process in the device for realizing optical field vector control through a scattering medium according to an embodiment of the present invention.

[0034] Figure 3 This is an optical path diagram of the speckle field phase conjugation and refocusing process in the device for realizing optical field vector control through a scattering medium according to an embodiment of the present invention.

[0035] Figure 4 This is a schematic diagram illustrating the encoding principle of the conjugate phase in the method and apparatus for achieving optical field vector control through a scattering medium according to an embodiment of the present invention.

[0036] Figure 1 and Figure 2 In the diagram: 1-Laser, 2-Beam expander and collimator, 3-Polarizer, 4-Polarizing beam splitter, 5-Polarization control device, 6-Reflector, 7-Converging lens, 8-Scattering medium, 9-Collimating lens, 10-Unpolarizing beam splitter, 11-Image acquisition device one, 12-Unpolarizing beam splitter, 13-Half-wave plate, 14-Spatial light modulation device one, 15-Spatial light modulation device two, 16-Converging lens, 17-Collimating lens, 18-Reflector, 19-Converging lens, 20-Image acquisition device two. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments and accompanying drawings. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0038] Example 1: See Figure 1 The present invention provides a method for controlling the optical field vector through a scattering medium, comprising the following steps:

[0039] S1, Speckle Field Complex Amplitude Recording Process: Based on off-axis digital holography and polarization angle multiplexing technology, left-handed circularly polarized light and right-handed circularly polarized light are sequentially passed through the scattering medium to form speckle fields S1 and S2, which then undergo compound interference with horizontally polarized reference light and vertically polarized reference light to form compound holograms H1(m,n) and H2(m,n), where (m,n) are discretized pixel coordinates;

[0040] S2. Process of obtaining the conjugate phase of the speckle field: The orthogonal polarization components of the complex amplitude of the speckle field formed by left-handed and right-handed circularly polarized light are demodulated from the composite holograms H1(m,n) and H2(m,n) using numerical reconstruction methods, and the conjugate phase distribution is further obtained by numerical calculation from the complex amplitude. Subscripts s and p represent the horizontal and vertical polarization components of the complex amplitude of the speckle field, respectively;

[0041] S3, Speckle Field Phase Conjugation and Refocusing Process: [The process involves...] and The image is converted to the image corresponding to the spatial light modulation device, and then encoded into the same grayscale image G1(m,n). Similarly, the image is converted to the image corresponding to the spatial light modulation device. and Encode them into the same image G2(m,n); load G1 and G2 onto two spatial light modulation devices simultaneously, and illuminate them with a reference light to obtain two phase conjugate beams. Use image acquisition device 2 to record the complex amplitude and polarization distribution of the superimposed focal point formed by the two phase conjugate beams.

[0042] S4. Phase conjugate beam vector modulation process: Different phase differences are applied to the conjugate phase distribution obtained in step S2, and the intensity ratio of the two reference beams is changed. According to the principle of vector beam synthesis and decomposition, the phase conjugate beam at this time is formed by the superposition of left-handed and right-handed circularly polarized light, and the intensity and phase of the left-handed and right-handed circularly polarized light are adjustable. The focal polarization distribution formed by the conjugate beam is recorded by the detection image acquisition device, thus completing the vector modulation of the beam through the scattering medium.

[0043] Preferably, the speckle field complex amplitude recording process corresponds to Figure 2 The optical path structure shown includes the following steps:

[0044] (S1-1) The visible light output from the continuous laser source 1 is converted into a linearly polarized beam after passing through the optical beam expander collimation system 2, and then modulated by the polarizer 3 to obtain a 45-degree linearly polarized beam, which is then split into a transmitted beam and a reflected beam by the polarizing beam splitter 4.

[0045] (S1-2) The reflected beam is modulated by the polarization modulation system 5 to obtain a left-hand circularly polarized beam, which passes through the reflector 6 and the converging lens 7 in sequence and is incident into the scattering medium 8. The scattered beam exiting from the scattering medium is collected by the converging lens 9, and after passing through the non-polarizing beam combiner 10, it reaches the target surface of the image acquisition device 11 to form a speckle field, denoted as S1.

[0046] (S1-3) The transmitted beam passes again through the unpolarized beam splitter 12 and the half-wave plate 13, splitting into horizontally polarized light R. 1S and vertically polarized light R 1PThe light beam is incident perpendicularly onto the surfaces of two reflective spatial light modulators 14 and 15, respectively. The polarization response direction of the spatial light modulator is consistent with the polarization direction of the light beam, and the light beam is in the off state.

[0047] (S1-4) After the two beams of light are directly reflected by the spatial light modulator, they are combined again by the non-polarizing beam splitter and then reach the target surface of the image acquisition device after passing through the 4f system composed of lens 16 and lens 17. The spatial position, pitch and rotation angles of the two reflective spatial light modulators and the image acquisition device are adjusted so that the two reflective spatial light modulators and the image acquisition device are in the conjugate plane of the 4f system.

[0048] (S1-5) Fine-tune the angle of the depolarizing beam combiner in front of the image acquisition device so that S1 and R S R P Off-axis interference occurs, forming a composite hologram H1(m,n), which is recorded by the imaging device; then, the left-handed circularly polarized light is adjusted to right-handed circularly polarized light, resulting in the speckle field S2 and the reference light R. S R P The off-axis interference again forms a composite hologram H2(m,n), which is recorded by the image acquisition device.

[0049] Preferably, the method used for obtaining the conjugate phase of the speckle field in the digital holographic complex amplitude reconstruction is the angular spectrum method.

[0050] Preferably, the speckle field phase conjugation and refocusing process corresponds to Figure 3 Specifically, it includes the following steps:

[0051] (S3-1) Conjugate phase and Converted into grayscale images G of spatial light modulators respectively 1S (m,n) and G 2S (m,n), using the pixel space reuse method, G 1S (m,n) and G 2S (m,n), fused and encoded into a grayscale image G1, similarly based on the conjugate phase. and The resulting fused coded grayscale image G2 is obtained, and the fusion coding method is as follows: Figure 4 As shown;

[0052] (S3-2) Load G1 and G2 onto two spatial light modulators respectively, and use the two reference beams separated in step S1 to illuminate the two spatial light modulators respectively.

[0053] (S3-3) Place a reflector 18 in the transmission direction of the non-polarizing beam splitter 10 in front of the image acquisition device, and adjust the spatial position, pitch and rotation angle of the reflector so that the reflector is also in the conjugate plane of the 4f system in step S1. At this time, the reflector and the target surface of the image acquisition device are symmetrical and equivalent about the non-polarizing beam splitter.

[0054] (S3-4) After the two phase conjugate beams are reflected by the reflector and the depolarizing beam combiner, they are transmitted in the opposite direction and pass through the lens, the scattering medium and the lens in sequence. Then the direction of the reflector 6 is rotated to the downward direction in the figure, and the beams are focused by the lens 19 onto the target surface of the image acquisition device 2.

[0055] Preferably, the phase conjugate beam vector modulation process specifically includes the following steps:

[0056] (S4-1) Based on the principle of vector light field decomposition and synthesis, calculate the phase difference and intensity ratio of the left and right circularly polarized components corresponding to the required polarized light distribution;

[0057] (S4-2) Adjust the intensity ratio of the incident light to the two spatial light modulators until the required value is met;

[0058] (S4-3) Maintain the conjugate phase G of the left-handed circularly polarized light respectively 1S (m,n) and G 1P Phase difference of (m,n) Constant, and the conjugate phase G of right-handed circularly polarized light 2S (m,n) and G 2P Phase difference of (m,n) Keep the overall phase difference between left-handed and right-handed circularly polarized beams constant, then change the overall phase difference between them. Achieve vector control of synthesized phase-conjugated light.

[0059] Example 2: Unlike Example 1, in the process of recording the complex amplitude of the speckle field, the polarization state of the beams incident on the scattering medium twice can be changed to a pair of horizontally polarized light and vertically polarized light.

[0060] The above are two preferred embodiments of the present invention. However, the embodiments of the present invention are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for controlling the optical field vector through a scattering medium, characterized in that, Includes the following steps: S1, Speckle Field Complex Amplitude Recording Process: Based on off-axis digital holography and polarization angle multiplexing technology, left-handed circularly polarized light and right-handed circularly polarized light are sequentially passed through the scattering medium to form speckle fields S1 and S2, which then undergo compound interference with horizontally polarized reference light and vertically polarized reference light to form compound holograms H1(m,n) and H2(m,n), where (m,n) are discretized pixel coordinates; S2. Process of obtaining the conjugate phase of the speckle field: The orthogonal polarization components of the complex amplitude of the speckle field formed by left-handed and right-handed circularly polarized light are demodulated from the composite holograms H1(m,n) and H2(m,n) using numerical reconstruction methods, and the conjugate phase distribution φ is further calculated numerically from the complex amplitude. 1s (m,n), φ 1p (m,n), φ 2s (m,n), φ 2p (m,n), where subscripts s and p represent the horizontal and vertical polarization components of the complex amplitude of the speckle field, respectively; S3, Speckle Field Phase Conjugation and Refocusing Process: φ 1s (m,n) and φ 2s (m,n) is converted into the image corresponding to the spatial light modulation device, and then encoded into the same grayscale image G1(m,n). Similarly, φ is... 1p (m,n) and φ 2p (m,n) are encoded into the same image G2(m,n); G1 and G2 are simultaneously loaded onto two spatial light modulation devices and illuminated with a reference light to obtain two phase conjugate beams; the complex amplitude and polarization distribution of the superimposed focal point formed by the two phase conjugate beams are recorded using image acquisition device 2. S4. Phase conjugate beam vector modulation process: Different phase differences are applied to the conjugate phase distribution obtained in step S2, and the intensity ratio of the two reference beams is changed. According to the principle of vector beam synthesis and decomposition, the phase conjugate beam at this time is formed by the superposition of left-handed and right-handed circularly polarized light, and the intensity and phase of the left-handed and right-handed circularly polarized light are adjustable. The focal polarization distribution formed by the conjugate beam is recorded by the detection image acquisition device, thus completing the vector modulation of the beam through the scattering medium.

2. The method for controlling the optical field vector through a scattering medium according to claim 1, characterized in that, The process of recording the complex amplitude of the speckle field in step S1 specifically includes the following steps: (S1-1) Visible light output from a continuous laser source is converted into a linearly polarized beam after passing through an optical beam expander and collimator system. Then, it is modulated by a polarizer to obtain a 45-degree linearly polarized beam, which is then split into a transmitted beam and a reflected beam by a polarizing beam splitter. (S1-2) The reflected beam is modulated by the polarization modulation system to obtain a left-hand circularly polarized beam, which passes through the reflector and the converging lens in sequence and is incident on the scattering medium. The scattered beam exiting from the scattering medium is collected by the converging lens, and after passing through the non-polarizing beam combiner, it reaches the target surface of the image acquisition device to form a speckle field, denoted as S1. (S1-3) The transmitted beam passes through the unpolarized beam splitter and half-wave plate again, splitting into horizontally polarized light R. 1S and vertically polarized light R 1P The light beam is incident perpendicularly onto the surfaces of two reflective spatial light modulators, whose polarization response direction is consistent with the beam polarization direction and which are in the off state. (S1-4) After the two beams of light are directly reflected by the spatial light modulator, they are combined again by the non-polarizing beam splitter and then reach the target surface of the image acquisition device after passing through the 4f system composed of two lenses. The spatial position, pitch and rotation angles of the two reflective spatial light modulators and the image acquisition device are adjusted so that the two reflective spatial light modulators and the image acquisition device are in the conjugate plane of the 4f system. (S1-5) Fine-tune the angle of the depolarization beam combiner in front of the image acquisition device so that S1 and R S R P Off-axis interference occurs, forming a composite hologram H1(m,n), which is recorded by the imaging device; then, the left-handed circularly polarized light is adjusted to right-handed circularly polarized light, resulting in the speckle field S2 and the reference light R. S R P The off-axis interference again forms a composite hologram H2(m,n), which is recorded by the image acquisition device.

3. The method for controlling the optical field vector through a scattering medium according to claim 2, characterized in that, In step S1, the polarizing beam splitter is used to cooperate with the polarizer during phase conjugation to achieve full transmission of the light beam; the reflective spatial light modulation device is in two states, namely off and on, during speckle field recording and conjugation.

4. The method for controlling the optical field vector through a scattering medium according to claim 1, characterized in that, In step S2, during the acquisition of the conjugate phase of the speckle field, the methods for obtaining the complex amplitude distribution from the hologram through numerical reconstruction include convolution, angular spectrum, Fresnel diffraction, and numerical reconstruction methods derived from Fresnel diffraction.

5. The method for controlling the optical field vector through a scattering medium according to claim 1, characterized in that, The process of speckle field phase conjugation and refocusing in step S3 specifically includes the following steps: (S3-1) The conjugate phase φ 1s (m,n) and φ 2s (m,n) are respectively converted into grayscale images G of the spatial light modulation device. 1S (m,n) and G 2S (m,n), using the pixel space reuse method, G 1S (m,n) and G 2S (m,n) are fused and encoded into a grayscale image G1. Similarly, the conjugate phase φ can be used to encode the data. 1p (m,n) and φ 2p (m,n) yields the fused coded grayscale image G2, and the fusion coding method is shown in Figure 4; (S3-2) Load G1 and G2 onto two spatial light modulators respectively, and use the two reference beams separated in step S1 to illuminate the two spatial light modulators respectively. (S3-3) Place a reflector in the transmission direction of the non-polarizing beam splitter in front of the image acquisition device, and adjust the spatial position, pitch and rotation angle of the reflector so that the reflector is also in the conjugate plane of the 4f system in step S1. At this time, the reflector and the target surface of the image acquisition device are symmetrical and equivalent about the non-polarizing beam splitter. (S3-4) After the two phase conjugate beams are reflected by the reflector and the depolarization beam combiner, they are transmitted in the opposite direction and pass through the lens, the scattering medium and the lens in sequence. Then the reflector is rotated to the downward direction in the figure and focused by the lens onto the target surface of the image acquisition device 2.

6. The method for controlling the optical field vector through a scattering medium according to claim 5, characterized in that, In step S3-1, the scheme for converting the conjugate phases from different speckle fields under the same polarization state into grayscale images and fusing them into a single image is to use adjacent pixel interleaved encoding fusion.

7. The method for controlling the optical field vector through a scattering medium according to claim 1, characterized in that, The phase conjugate beam polarization modulation process described in step S4 specifically includes the following steps: (S4-1) Based on the principle of vector light field decomposition and synthesis, calculate the phase difference and intensity ratio of the left and right circularly polarized components corresponding to the required polarized light distribution; (S4-2) Adjust the intensity ratio of the incident light to the two spatial light modulators until the required value is met; (S4-3) Maintain the conjugate phase G of the left-handed circularly polarized light respectively 1S (m,n) and G 1P The phase difference ∆φ1 between (m,n) is constant, and the conjugate phase G of right-hand circularly polarized light is constant. 2S (m,n) and G 2P The phase difference ∆φ2 of (m,n) is kept constant. Then, the overall phase difference δφ = ∆φ1 - ∆φ2 of the left-hand and right-hand circularly polarized beams is changed to achieve polarization control of the synthesized phase conjugate light.

8. The method for controlling the optical field vector through a scattering medium according to claim 7, characterized in that, In the process of changing the overall phase difference between the left-handed and right-handed circularly polarized beams as described in step S4-3, each set of independent conjugate phase distributions can only be changed as a whole, and their individual distributions cannot be altered.

9. The method for controlling the optical field vector through a scattering medium according to claim 7, characterized in that, In the phase conjugate beam polarization modulation process described in step S4, the phase conjugate beam generated by modulation needs to be able to be decomposed into left-handed and right-handed circularly polarized beams with a certain phase difference and amplitude ratio.

10. An apparatus for implementing the method of optical field vector manipulation through a scattering medium as described in claim 1, characterized in that, The system includes a laser, a beam expander and collimator, a polarizer, a half-wave plate, a polarization control system, two mirrors, a scattering medium, five lenses, a polarizing beam splitter, two unpolarizing beam splitters, two spatial light modulators, two image acquisition devices, and a computer. The laser light is sequentially passed through the beam expander and collimator and the polarizer to obtain a 45-degree linearly polarized beam. This beam is then split into two beams by the polarizing beam splitter. The reflected beam is polarized by the polarization control system to obtain left-handed circularly polarized light. After being reflected by the mirrors, it is converged by the lenses, passes through the scattering medium, is collected and collimated by the lenses, and then passes through the unpolarizing beam splitter to reach the target surface of the image acquisition device. Finally, it is transmitted through the polarizing beam splitter. The beam is split into two beams again by the non-polarizing beam splitter. One beam is modulated by the half-wave plate and then incident on the two spatial light modulators. After being reflected, it is re-combined by the non-polarizing beam splitter and imaged onto the target surface of image acquisition device one by a 4f imaging system composed of two lenses. It then undergoes angular multiplexing interference with the speckle field to form a hologram. During the phase conjugation and refocusing process of the speckle field, a reflector is placed at a position symmetrical about the non-polarizing beam splitter on image acquisition device one, and the reflector in front of the scattering medium is rotated by 90 degrees. This allows the phase conjugated beam to exit from the reflector and be converged onto image acquisition device two by the lens, realizing real-time detection of the phase conjugated beam focusing effect and polarization control result.

11. The apparatus for controlling the optical field vector through a scattering medium according to claim 10, characterized in that, The beam expander and collimator consists of a lens group and a pinhole filter; the spatial light modulator is a phase-type liquid crystal spatial light modulator; and the image acquisition device is a CCD or CMOS camera.

12. The apparatus for controlling the optical field vector through a scattering medium according to claim 10, characterized in that, The polarization control system consists of polarizers, half-wave plates, and quarter-wave plates, or adjustable liquid crystal polarization devices, and can convert linearly polarized beams into left- or right-hand circularly polarized beams.

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