Light field control system and method based on laser array coherent synthesis

Abstract

The present invention discloses a light field control system and method based on laser array coherent synthesis, wherein a laser array generation module is used to output a high-power array beam; a spatial beam reduction optical path in the light field control module samples the array beam and performs beam reduction processing so that the light field area of ​​the beam-reduced array beam can match the effective target size of a spatial light modulator; two spatial light modulators respectively control the phase and polarization of the two orthogonal polarization components of the beam-reduced array beam, and transmit the controlled beams to a phase and polarization locking circuit; the phase and polarization locking circuit generates a phase control signal and a polarization control signal based on the controlled beam output by the light field control module, and applies them to the phase modulator and polarization controller of each unit laser in the laser array generation module to achieve phase and polarization locking of the high-power array beam. The present invention can achieve flexible light field control of the far-field synthetic light spot of the array beam.

Description

Technical Field

[0001] The present invention belongs to the technical field of light field control, and more specifically, relates to a light field control system and method based on laser array coherent synthesis. Background Art

[0002] Light field manipulation technology manipulates the spatial amplitude, phase, and polarization distribution of light fields, enabling them to exhibit numerous novel phenomena and effects during transmission, transformation, and interaction with matter. With its unique advantages and broad application prospects, light field manipulation technology has gradually developed into a highly anticipated independent branch of optics. With the development of fields such as high-power laser processing and space optical communications, the demand for light fields is constantly escalating, requiring not only stronger mode manipulation capabilities but also higher power output. Currently, common light field manipulation technologies generally face the inherent contradiction between mode switching flexibility and power enhancement, making it difficult to simultaneously meet these two requirements. Summary of the Invention

[0003] In view of the defects of the existing technology, the present invention proposes a light field control system and method based on laser array coherent synthesis.

[0004] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0005] In one aspect, the present invention provides a light field control system based on laser array coherent combining, comprising:

[0006] A laser array generation module, used for outputting high-power array beams;

[0007] The light field control module includes a spatial beam reduction optical path and two spatial light modulators. The spatial beam reduction optical path reduces the sampled array beam so that the optical field area of ​​the reduced array beam matches the effective target size of the spatial light modulator. The two spatial light modulators separately control the phase and polarization of the two orthogonal polarization components of the reduced array beam and transmit the controlled beams to the phase and polarization locking loop.

[0008] The phase and polarization locking circuit generates a phase control signal and a polarization control signal based on the regulated light beam output by the light field control module, and applies them to the phase modulator and polarization controller of each unit laser in the laser array generation module to achieve phase and polarization locking of the high-power array beam.

[0009] On the other hand, a light field control method of the light field control system based on laser array coherent combining is provided, comprising:

[0010] The laser array generation module outputs a high-power array beam;

[0011] A small portion of the power of the array beam is collected as a sampling array beam for beam reduction processing, so that the light field area of ​​the reduced array beam can match the effective target size of the spatial light modulator. The two spatial light modulators respectively control the phase and polarization of the two orthogonal polarization components of the reduced array beam.

[0012] A phase control signal and a polarization control signal are generated based on the regulated light beam and applied to the phase modulator and polarization controller of each unit laser in the laser array generation module. The piston phase and polarization state of each unit laser are adjusted so that the phase and polarization distribution of the high-power array beam output by the system match the expected settings of the spatial light modulator, thereby achieving phase and polarization locking of the high-power array beam. At this time, the light field of the high-power array beam output by the system meets the preset polarization and phase distribution requirements.

[0013] The method of the present invention can achieve the following technical effects:

[0014] The present invention provides a light field control system and method based on laser array coherent synthesis, which is divided into three parts: a laser array generation module, a light field control module, and a phase and polarization locking loop. The laser array generation module is used to output a high-power array light beam. The laser array coherent synthesis technology can break through the power limit of a single laser, significantly improving the laser power while maintaining good beam quality. The light field control module is used to precisely control the phase and polarization of the laser array light field. The phase and polarization locking loop is used to generate real-time phase and polarization control signals, and apply them to the phase modulator and polarization controller of each unit laser to achieve system phase and polarization locking. Each laser unit of the present invention has the ability to independently control the amplitude, phase and polarization parameters, and can achieve flexible light field control of its far-field synthetic light spot, ensuring that the light field of the system output laser array meets the preset polarization and phase distribution requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0016] Figure 1 The figure is a schematic structural diagram of a light field control system based on a laser array provided in one embodiment of the present invention.

[0017] Figure 2 This is a schematic structural diagram of another laser array-based light field control system provided in one embodiment of the present invention.

[0018] Description of reference numerals:

[0019] 1. Seed laser; 2. 1×N laser beam splitter; 3. N phase modulators; 4. N polarization controllers; 5. N laser amplifiers; 6. N laser collimators; 7. Laser beam combiner; 8. Beam splitter; 9. First convex lens; 10. Second convex lens; 11. 1 / 4 wave plate; 12. Depolarizing beam splitter prism; 13. Polarizing beam splitter prism; 14. 1 / 2 wave plate; 15. 2 spatial light modulators; 16. Modulated phase generator; 17. Polarizer; 18. Third convex lens; 19. Pinhole aperture; 20. Photodetector; 21. Phase control module; 22. Polarization control module.

[0020] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0021] In order to make the technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Thus, a feature identified as "first," "second," or "third" may explicitly or implicitly include at least one of such features.

[0023] One embodiment provides a light field control system based on laser array coherent combining, including a laser array generation module, a light field control module, and a phase and polarization locking loop.

[0024] A laser array generation module, used for outputting high-power array beams;

[0025] The light field control module includes a spatial beam reduction optical path and two spatial light modulators. The spatial beam reduction optical path reduces the sampled array beam so that the optical field area of ​​the reduced array beam matches the effective target size of the spatial light modulator. The two spatial light modulators separately control the phase and polarization of the two orthogonal polarization components of the reduced array beam and transmit the controlled beams to the phase and polarization locking loop.

[0026] The phase and polarization locking circuit generates a phase control signal and a polarization control signal based on the regulated light beam output by the light field control module, and applies them to the phase modulator and polarization controller of each unit laser in the laser array generation module to achieve phase and polarization locking of the high-power array beam.

[0027] Reference Figure 1 In one embodiment, a light field control system based on laser array coherent synthesis is provided. Specifically, the laser array generation module includes a seed laser 1, a 1×N laser beam splitter 2, N phase modulators 3, N polarization controllers 4, N laser amplifiers 5, N laser collimators 6, a laser beam combiner 7 and a beam splitter 8.

[0028] The output end of the seed laser 1 is connected to the input end of the 1×N laser beam splitter, and the seed laser output by the seed laser 1 is divided into N unit lasers after passing through the 1×N laser beam splitter 2;

[0029] The N output ends of the 1×N laser beam splitter 2 are connected to the corresponding phase modulator 3, polarization controller 4, laser amplifier 5, and laser collimator 6 in sequence. Each unit laser passes through the phase modulator 3 in sequence for phase control, polarization control is achieved through the polarization controller 4, power amplification is completed in the laser amplifier 5, and collimated output is achieved through the laser collimator 6.

[0030] The output beams of the N laser collimators 6 are transmitted to the laser beam combiner 7 , which combines the N unit lasers to reduce the spacing between the unit lasers and form a tightly arranged array beam.

[0031] The array beam output by the laser beam combiner 7 is transmitted to the beam splitter 8, which divides the array beam into two parts. The transmitted high-power array beam serves as the output of the system to achieve the preset light field distribution in the far field; the remaining small part of the reflected array beam is transmitted as a sampling array beam to the light field control module for the system's light field control.

[0032] The light field control module is used to precisely control the phase and polarization of the laser array light field. It includes two parts: a spatial beam reduction optical path and a dual-channel spatial light modulator architecture. The spatial beam reduction optical path performs beam reduction processing on the sampling laser array so that its light field area can match the effective target size of the spatial light modulator. In this embodiment, the spatial beam reduction optical path adopts a Kepler telescope structure and includes a first convex lens 9 and a second convex lens 10. The first convex lens 9 and the second convex lens 10 are arranged in a confocal manner, and the spacing between the first convex lens 9 and the second convex lens 10 is equal to the sum of the focal lengths of the first convex lens 9 and the second convex lens 10. The first convex lens 9 receives the sampling array light beam. The light aperture of the first convex lens 9 is larger than the size of the circumscribed circle of the sampling array light beam, ensuring that all N unit lasers can be incident on the beam reduction optical path. At the same time, the focal length of the first convex lens 9 is larger than the focal length of the second convex lens 10. The achieved beam reduction ratio is the ratio of the focal lengths of the first convex lens 9 and the second convex lens 10. By properly designing the diameters and focal lengths of the first convex lens 9 and the second convex lens 10 , the size of the sampling laser array after beam reduction can match the effective target surface size of the two spatial light modulators 15 .

[0033] The dual-channel spatial light modulator architecture uses two independent spatial light modulators 15 to precisely control the two orthogonal polarization components (the horizontal polarization p component and the vertical polarization s component) of the beam-contracted laser array. The present invention provides two ways to implement this architecture: Figure 1 The embodiment shown adopts a polarization beam splitting method, that is, a polarization beam splitter prism is used to separate the array light beam after the beam is reduced into two paths, p-light and s-light. Two spatial light modulators respectively control the phase and polarization of the p-light and s-light, and then combine them through coaxial superposition to transmit them to the phase and polarization locking loop.

[0034] Specifically, the light field control module also includes a 1 / 4 wave plate 11, a depolarizing beam splitter prism 12, a polarizing beam splitter prism 13 and a modulation phase generator 16. The array light beam after being beam-contracted is converted into elliptically polarized light by the 1 / 4 wave plate 11, and then enters the depolarizing beam splitter prism 12. The light beam transmitted through the depolarizing beam splitter prism 12 is leakage light and is discarded. The light beam reflected by the depolarizing beam splitter prism 12 is further incident on the polarizing beam splitter prism 13 and is divided into two beams with mutually perpendicular polarization directions, wherein the transmitted light is p light and the reflected light is s light; the p light and the s light are respectively transmitted to the corresponding spatial light modulator 1 5 performs phase modulation; since the spatial light modulator 15 only phase modulates the polarization direction perpendicular to the long axis of the liquid crystal, and has no phase modulation effect on the polarization direction parallel to the long axis of the liquid crystal, each spatial light modulator 15 needs to be rotated to an appropriate angle to match its polarization operating direction; both spatial light modulators 15 are connected to a modulation phase generator 16, which generates two phase modulation signals based on a preset light field distribution model and loads them onto the corresponding spatial light modulator 15, thereby precisely controlling the phase and polarization distribution of the light field incident on the two spatial light modulators 15. The light field reflected by each spatial light modulator 15 will carry the preset phase information and will be reflected back along the original path to the polarization beam splitter prism 13 for re-combination. The combined light beam is then incident on the depolarization beam splitter prism 12 again, and the light beam transmitted through the depolarization beam splitter prism 12 is incident on the phase and polarization locking circuit.

[0035] The spatial light modulator 15 only modulates the phase of polarization perpendicular to the long axis of its liquid crystal. Typically, the long side of the spatial light modulator's physical shape represents the polarization direction. In Example 1, the transmitted light of the polarization beam splitter prism 12 is p-polarized light (horizontally polarized), and the reflected light is s-polarized light (vertically polarized). Positioning the long side of the spatial light modulator horizontally modulates p-polarized light, while positioning it vertically modulates s-polarized light.

[0036] The phase and polarization locking circuit includes a polarizer 17, a third convex lens 18, a pinhole aperture 19, a photodetector 20, a phase control module 21, and a polarization control module 22. The light beam output by the light field control module is incident on the polarizer 17 for polarization detection. The polarization direction of the polarizer 17 is consistent with the fast axis direction of the 1 / 4 wave plate 11. When the polarization and phase distribution of the array light beam incident on the light field control module match the expected settings of the spatial light modulator, a linearly polarized light beam with the same polarization direction as the polarizer will be output.

[0037] The light beam output by the polarizer 17 is transmitted to the third convex lens 18 for focusing. A pinhole aperture 19 and a photodetector 20 are placed at the focus of the third convex lens 18 to extract the central main lobe energy of the far-field spot of the light beam. The electrical signal generated by the photodetector 20 is output to the phase control module 21 and the polarization control module 22 respectively. The phase control module 21 and the polarization control module 22 can generate corresponding real-time control signals based on the electrical signals. The phase control signal generated by the phase control module 21 is applied to the phase modulator 3 of each unit laser to adjust the piston phase of each unit laser. The polarization control signal generated by the polarization control module 22 is applied to the polarization controller 4 of each unit laser to adjust the polarization state of each unit laser so that the phase and polarization distribution of the high-power array beam output by the system match the expected settings of the spatial light modulator. The detection signal of the photodetector 20 reaches the maximum value, realizing the phase and polarization locking of the high-power array beam. At this time, the light field of the high-power array beam output by the system meets the preset polarization and phase distribution requirements. Both the phase control module 21 and the polarization control module 22 are preloaded with optimization algorithms that generate corresponding real-time control signals based on the electrical signals. The optimization algorithms preloaded on the phase control module 21 and the polarization control module 22 are not limited and can employ various existing optimization algorithms, such as dithering algorithms and SPGD algorithms.

[0038] Reference Figure 2 , an optical field control system based on laser array coherent synthesis is provided in one embodiment, wherein Figure 2 The laser array generation module in the embodiment shown is Figure 1 The laser array generation modules in the illustrated embodiments are the same, and the laser array generation modules also include a seed laser 1, a 1×N laser beam splitter 2, N phase modulators 3, N polarization controllers 4, N laser amplifiers 5, N laser collimators 6, a laser beam combiner 7 and a beam splitter 8.

[0039] The output end of the seed laser 1 is connected to the input end of the 1×N laser beam splitter, and the seed laser output by the seed laser 1 is divided into N unit lasers after passing through the 1×N laser beam splitter 2;

[0040] The N output ends of the 1×N laser beam splitter 2 are connected to the corresponding phase modulator 3, polarization controller 4, laser amplifier 5, and laser collimator 6 in sequence. Each unit laser passes through the phase modulator 3 in sequence for phase control, polarization control is achieved through the polarization controller 4, power amplification is completed in the laser amplifier 5, and collimated output is achieved through the laser collimator 6.

[0041] The output beams of the N laser collimators 6 are transmitted to the laser beam combiner 7 , which combines the N unit lasers to reduce the spacing between the unit lasers and form a tightly arranged array beam.

[0042] The array beam output by the laser beam combiner 7 is transmitted to the beam splitter 8, which divides the array beam into two parts. The transmitted high-power array beam serves as the output of the system to achieve the preset light field distribution in the far field; the remaining small part of the reflected array beam is transmitted as a sampling array beam to the light field control module for the system's light field control.

[0043] The light field control module is used to precisely control the phase and polarization of the laser array light field. It includes two parts: a spatial beam reduction optical path and a dual-channel spatial light modulator architecture. The spatial beam reduction optical path performs beam reduction processing on the sampling laser array so that its light field area can match the effective target size of the spatial light modulator. In this embodiment, the spatial beam reduction optical path adopts a Kepler telescope structure and includes a first convex lens 9 and a second convex lens 10. The first convex lens 9 and the second convex lens 10 are arranged in a confocal manner, and the spacing between the first convex lens 9 and the second convex lens 10 is equal to the sum of the focal lengths of the first convex lens 9 and the second convex lens 10. The first convex lens 9 receives the sampling array light beam. The light aperture of the first convex lens 9 is larger than the size of the circumscribed circle of the sampling array light beam, ensuring that all N unit lasers can be incident on the beam reduction optical path. At the same time, the focal length of the first convex lens 9 is larger than the focal length of the second convex lens 10. The achieved beam reduction ratio is the ratio of the focal lengths of the first convex lens 9 and the second convex lens 10. By properly designing the diameters and focal lengths of the first convex lens 9 and the second convex lens 10 , the size of the sampling laser array after beam reduction can match the effective target surface size of the two spatial light modulators 15 .

[0044] The dual-channel spatial light modulator architecture uses two independent spatial light modulators 15 to precisely control the two orthogonal polarization components (the horizontal polarization p component and the vertical polarization s component) of the beam-contracted laser array. The present invention provides two ways to implement this architecture: Figure 2 The illustrated embodiment employs a cascaded reflective approach, employing a reflective optical path of cascaded spatial light modulators in conjunction with a half-wave plate 14 to rotate the polarization direction of the array beam, sequentially modulating the different polarization components of the beam after being condensed. Specifically, the condensed array beam is converted into elliptically polarized light by the quarter-wave plate 11 and then incident on the first spatial light modulator 15. The first spatial light modulator 15 performs phase modulation on the first polarization component of the array beam that conforms to its polarization operating direction. The array beam reflected by the first spatial light modulator 15 is rotated by the half-wave plate 14, so that the second polarization component of the array beam conforms to the polarization operating direction of the second spatial light modulator 15. The second spatial light modulator 15 then performs phase modulation on the second polarization component of the array beam that conforms to its polarization operating direction. The phase-modulated light field carries the preset phase information and is incident on the phase and polarization locking loop.

[0045] The spatial light modulator 15 only modulates the phase of the polarization direction perpendicular to the long axis of its liquid crystal. Typically, spatial light modulators use the long side of their physical shape to indicate the direction of their polarization. In Example 2, both spatial light modulators are positioned with their long sides horizontal. The first spatial light modulator modulates only the p-polarization component in the array beam, while the s-polarization component remains unchanged. Subsequently, the fast axis of the half-wave plate 14 is angled 45° with the horizontal, rotating the polarization direction of the array beam by 90°. The original s-polarization component is converted to a p-polarization component, which is modulated by the second spatial light modulator.

[0046] Figure 2 The phase and polarization locked loop in the embodiment shown is Figure 1 The phase and polarization locking circuit in the illustrated embodiment is the same, and also includes a polarizer 17, a third convex lens 18, a pinhole aperture 19, a photodetector 20, a phase control module 21, and a polarization control module 22. The light beam output by the light field manipulation module is incident on the polarizer 17 for polarization detection. The polarization direction of the polarizer 17 is consistent with the fast axis direction of the 1 / 4 wave plate 11. When the polarization and phase distribution of the array light beam incident on the light field manipulation module matches the expected settings of the spatial light modulator, a linearly polarized light beam with the same polarization direction as the polarizer will be output.

[0047] The light beam output by the polarizer 17 is transmitted to the third convex lens 18 for focusing. A pinhole aperture 19 and a photodetector 20 are placed at the focus of the third convex lens 18 to extract the central main lobe energy of the far-field spot of the light beam. The electrical signal generated by the photodetector 20 is output to the phase control module 21 and the polarization control module 22 respectively. The phase control module 21 and the polarization control module 22 can generate corresponding real-time control signals based on the electrical signals. The phase control signal generated by the phase control module 21 is applied to the phase modulator 3 of each unit laser to adjust the piston phase of each unit laser. The polarization control signal generated by the polarization control module 22 is applied to the polarization controller 4 of each unit laser to adjust the polarization state of each unit laser so that the phase and polarization distribution of the high-power array beam output by the system match the expected settings of the spatial light modulator. The detection signal of the photodetector 20 reaches the maximum value, realizing the phase and polarization locking of the high-power array beam. At this time, the light field of the high-power array beam output by the system meets the preset polarization and phase distribution requirements. Both the phase control module 21 and the polarization control module 22 are preloaded with optimization algorithms that generate corresponding real-time control signals based on the electrical signals. The optimization algorithms preloaded on the phase control module 21 and the polarization control module 22 are not limited and can employ various existing optimization algorithms, such as dithering algorithms and SPGD algorithms.

[0048] It can be seen that whether it is Figure 1 The polarization splitting type of embodiment 1 is also Figure 2 In the cascade reflection method of embodiment 2 shown, both methods require the coordinated operation of a quarter-wave plate 11 and a polarizer 17. The quarter-wave plate 11 is placed at the front end of the structure, and the polarizer 17 is placed at the back end. The quarter-wave plate 11 converts the sampling laser array into elliptically polarized light (including linearly polarized light and circularly polarized light as special cases). The polarization direction of the polarizer 17 is consistent with the fast axis direction of the quarter-wave plate 11 for polarization direction detection. When the polarization and phase distribution of the light beam array incident on the optical path of the light field control module match the settings of the spatial light modulator 15, a linearly polarized light beam with the same polarization direction as the polarizer will be output. In addition, a modulation phase generator 16 (usually a computer control system) is required to generate two phase modulation signals based on a preset light field distribution model and load them onto the corresponding spatial light modulator 16, thereby precisely controlling the phase and polarization distribution of the laser array light field.

[0049] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present application, and such modifications and improvements are all within the scope of protection of the present application.

Claims

1. A light field control system based on laser array coherent synthesis, characterized by: include: A laser array generation module, used for outputting high-power array beams; The light field control module includes a spatial beam reduction optical path and two spatial light modulators. The spatial beam reduction optical path reduces the sampled array beam so that the optical field area of ​​the reduced array beam matches the effective target size of the spatial light modulator. The two spatial light modulators separately control the phase and polarization of the two orthogonal polarization components of the reduced array beam and transmit the controlled beams to the phase and polarization locking loop. The phase and polarization locking circuit generates a phase control signal and a polarization control signal based on the regulated light beam output by the light field control module, and applies them to the phase modulator and polarization controller of each unit laser in the laser array generation module to achieve phase and polarization locking of the high-power array beam.

2. The light field control system based on laser array coherent combining according to claim 1, characterized in that: The laser array generation module includes a seed laser, a 1×N laser beam splitter, N phase modulators, N polarization controllers, N laser amplifiers, N laser collimators, a laser beam combiner and a beam splitter; The output end of the seed laser is connected to the input end of the laser beam splitter. The seed laser output by the seed laser is divided into N unit lasers after passing through the 1×N laser beam splitter. The N output ends of the 1×N laser beam splitter are connected to the corresponding phase modulator, polarization controller, laser amplifier, and laser collimator in sequence. Each unit laser passes through the phase modulator in sequence for phase control, polarization control is achieved through the polarization controller, power amplification is completed in the laser amplifier, and collimated output is achieved through the laser collimator; The output beams of N laser collimators are transmitted to the laser beam combiner, which splices N unit lasers, reduces the distance between the unit lasers, and forms a tightly arranged array beam; The array beam output by the laser beam combiner is transmitted to the beam splitter, which divides the array beam into two parts. The transmitted high-power array beam serves as the output of the system, realizing the preset light field distribution in the far field; the remaining small part of the reflected array beam is transmitted as the sampling array beam to the light field control module for the system's light field control.

3. The light field control system based on laser array coherent combining according to claim 1 or 2, characterized in that: The spatial beam reduction optical path adopts a Kepler telescope structure, including a first convex lens and a second convex lens.

4. The light field control system based on laser array coherent combining according to claim 3, characterized in that: The first convex lens and the second convex lens are arranged in a confocal manner, and a distance between the first convex lens and the second convex lens is equal to the sum of the focal lengths of the first convex lens and the second convex lens.

5. The light field control system based on laser array coherent combining according to claim 4, characterized in that: The first convex lens receives the sampling array light beam. The aperture of the first convex lens is larger than the size of the circumscribed circle of the sampling array light beam, ensuring that all N unit lasers can be incident on the beam reduction light path. At the same time, the focal length of the first convex lens is larger than the focal length of the second convex lens. The achieved beam reduction ratio is the ratio of the focal lengths of the first convex lens and the second convex lens.

6. The light field control system based on laser array coherent combining according to claim 4 or 5, characterized in that: The light field control module uses a polarization beam splitter to separate the beam into two paths, p-light and s-light, after being beam-contracted. Two spatial light modulators respectively control the phase and polarization of the p-light and s-light, and then combine them through coaxial superposition and transmit them to the phase and polarization locking loop.

7. The light field control system based on laser array coherent combining according to claim 6, characterized in that: The light field control module also includes a 1 / 4 wave plate, a depolarizing beam splitter prism, a polarizing beam splitter prism and a modulation phase generator. The array light beam after beam reduction is converted into elliptically polarized light by the 1 / 4 wave plate, and then enters the depolarizing beam splitter prism. The light beam transmitted by the depolarizing beam splitter prism is leakage light and is discarded. The light beam reflected by the depolarizing beam splitter prism is further incident on the polarizing beam splitter prism and is divided into two beams with mutually perpendicular polarization directions, of which the transmitted light is p light and the reflected light is s light; the p light and s light are respectively transmitted to the corresponding spatial light modulator for phase shifting. Bit modulation; Since the spatial light modulator only has a phase modulation effect on the polarization direction perpendicular to the long axis of its liquid crystal, but has no phase modulation effect on the polarization direction parallel to the long axis of its liquid crystal, it is necessary to rotate the spatial light modulator to an appropriate angle to match its polarization working direction; Both spatial light modulators are connected to a modulation phase generator, which generates two phase modulation signals based on a preset light field distribution model and loads them onto the corresponding spatial light modulators respectively, thereby accurately controlling the phase and polarization distribution of the light field incident on the two spatial light modulators; The light field reflected by each spatial light modulator will carry the preset phase information and reflect back to the polarization beam splitter prism to be re-combined. The combined light beam is incident on the depolarization beam splitter prism again. The light beam transmitted by the depolarization beam splitter prism is incident on the phase and polarization locking loop.

8. The light field control system based on laser array coherent combining according to claim 4 or 5, characterized in that: The light field control module uses the reflective optical path of the cascaded spatial light modulator and cooperates with a 1 / 2 wave plate to rotate the polarization direction of the array beam, and modulates the different polarization components of the beam after the beam is shrunk. The beam after the beam is shrunk is converted into elliptically polarized light by the 1 / 4 wave plate and then incident on the first spatial light modulator. The first spatial light modulator phase modulates the first polarization component of the array beam that conforms to its polarization working direction. The array beam reflected by the first spatial light modulator rotates its polarization direction by the 1 / 2 wave plate so that the second polarization component of the array beam conforms to the polarization working direction of the second spatial light modulator. The second spatial light modulator phase modulates the second polarization component of the array beam that conforms to its polarization working direction. The phase-modulated light field will carry the preset phase information and be incident on the phase and polarization locking loop.

9. The light field control system based on laser array coherent combining according to claim 1, 2, 4, or 5, characterized in that: The phase and polarization locking circuit includes a polarizer, a third convex lens, a pinhole aperture, a photodetector, a phase control module, and a polarization control module. The light beam output by the light field control module is incident on the polarizer for polarization detection. The polarization direction of the polarizer is consistent with the fast axis direction of the 1 / 4 wave plate. When the polarization and phase distribution of the array light beam incident on the light field control module match the expected settings of the spatial light modulator, a linearly polarized beam with the same polarization direction as the polarizer will be output. The light beam output by the polarizer is transmitted to the third convex lens for focusing. A pinhole diaphragm and a photodetector are placed at the focus of the third convex lens to extract the central main lobe energy of the far-field spot of the light beam. The electrical signals generated by the photodetector are output to the phase control module and the polarization control module respectively. The phase control module and the polarization control module can generate corresponding real-time control signals based on the electrical signals. The phase control signal generated by the phase control module is applied to the phase modulator of each unit laser to adjust the piston phase of each unit laser; the polarization control signal generated by the polarization control module is applied to the polarization controller of each unit laser to adjust the polarization state of each unit laser so that the phase and polarization distribution of the high-power array beam output by the system match the expected settings of the spatial light modulator. The detection signal of the photodetector reaches the maximum value, and the phase and polarization locking of the high-power array beam is achieved. At this time, the light field of the high-power array beam output by the system meets the preset polarization and phase distribution requirements.

10. The light field control method of the light field control system based on laser array coherent combining according to claim 1, characterized in that: include: The laser array generation module outputs a high-power array beam; A small portion of the power of the array beam is collected as a sampling array beam for beam reduction processing, so that the light field area of ​​the reduced array beam can match the effective target size of the spatial light modulator. The two spatial light modulators respectively control the phase and polarization of the two orthogonal polarization components of the reduced array beam. A phase control signal and a polarization control signal are generated based on the regulated light beam and applied to the phase modulator and polarization controller of each unit laser in the laser array generation module. The piston phase and polarization state of each unit laser are adjusted so that the phase and polarization distribution of the high-power array beam output by the system match the expected settings of the spatial light modulator, thereby achieving phase and polarization locking of the high-power array beam. At this time, the light field of the high-power array beam output by the system meets the preset polarization and phase distribution requirements.

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