Method for generating structured light through laser array phase locking based on physical model gradient descent

Abstract

The invention provides a method for generating structured light through phase locking of a laser array based on gradient descent of a physical model, and relates to the technical field of structured light generation. According to the method, on a transmission path of light beams emitted by a coherent laser array, through a beam splitting and focusing light path, observation light intensity is collected on a defocusing plane at a preset distance after focusing of a focusing lens; constructing a phase estimation optimization problem based on a forward physical model of the coherent laser array, minimizing a mean square error of a physical reconstruction light intensity pattern and an observation light intensity pattern through a physical model gradient descent method, and dynamically estimating phase distribution of the coherent laser array; and based on the target phase distribution corresponding to the target structured light field, generating a phase compensation signal of each sub-beam in the coherent laser array, thereby generating the target structured light field in a far field. The system does not need additional optical devices, is high in universality, is high in phase locking response speed, is high in generated structured light mode purity, supports rapid mode switching, and is suitable for various scenes such as optical communication, super-resolution imaging and the like.

Description

Technical Field

[0001] This invention relates to the field of structured light generation and laser array control technology, specifically a method for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model. This method is suitable for the flexible generation of high-power, mode-programmable structured light and can be widely applied in cutting-edge fields such as optical communication, super-resolution imaging, and optical capture. Background Technology

[0002] Structured light, with its unique spatial distribution of intensity, phase, or polarization, plays an irreplaceable role in advanced fields such as optical communication, super-resolution imaging, and optical capture. Currently, structured light generation methods mainly fall into two categories: one involves mode conversion of the fundamental mode Gaussian beam using optical devices such as spatial light modulators, phase plates, and metasurfaces; the other involves designing intracavity components to resonate an oscillator in a specific mode, thereby extracting the target structured light field for output.

[0003] However, these traditional methods have significant limitations: they are limited by the power processing threshold and response rate of optical devices, making it difficult to achieve high-power structured light output and rapid dynamic switching; and traditional optical materials are prone to thermal effects and nonlinear distortion under high power conditions, which further restricts the performance of structured light.

[0004] Coherent laser arrays offer a new approach to generating high-power structured light by flexibly designing the arrangement, intensity, and phase distribution of the beam array. Through multi-beam coherent combining, they effectively overcome the bottleneck of structured light power enhancement. Paired with an ultrafast phase modulator with gigahertz-level response, they can support rapid control and switching of the piston phase of array subbeams, becoming a potential platform for realizing high-power, fast-switching structured light modulation.

[0005] Effective phase control of laser arrays is a crucial prerequisite for achieving structured light output. Existing phase control methods include stochastic parallel gradient descent (SPGD), reference beam interferometry, and machine learning, but most of these methods focus on achieving coherent phase alignment between array beams. However, generating structured light with complex wavefronts requires locking the array phase to a specific distribution, which is fundamentally different from traditional phase-locking targets and urgently requires innovative phase control strategies.

[0006] Existing phase control methods for structured light generation have many shortcomings: reference beam interferometry requires the introduction of adjacent beams, which increases system complexity and the difficulty of manipulating structured light; SPGD-based methods require the design of a dedicated cost function based on the characteristics of the target structured light, and manual adjustment is required when the target beam changes, resulting in low versatility and efficiency; some methods require the integration of optical devices such as spatial light modulators and liquid crystals, which limits the performance of structured light in terms of power expansion and dynamic switching; and existing methods are mostly designed around vortex beams, making them difficult to apply to the generation of other types of structured light.

[0007] Therefore, developing a phase-locked method for laser arrays that requires no additional optical components, is highly versatile, and can quickly lock arbitrary phase distributions is of great significance for realizing the flexible generation of high-power, mode-programmable structured light. Summary of the Invention

[0008] This invention aims to overcome the problems of limited power, slow dynamic switching, poor versatility of phase control, and high system complexity in existing structured light generation technologies. It provides a method for generating structured light by phase-locking of a laser array based on gradient descent of a physical model. This method can achieve precise locking of any target phase distribution without the need for additional optical devices and flexibly generate various types of high-power structured light.

[0009] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0010] On the one hand, a method for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model is provided, including: S1, determine the target structure light field and the corresponding target phase distribution, and set the initial array parameters of the coherent laser array, including sub-beam amplitude, initial phase and array geometric distribution; S2, along the transmission path of the emitted beam of the coherent laser array, the far-field light intensity is collected at the focal plane of the focusing lens through beam splitting and focusing optical paths, and the observed light intensity is collected at the defocus plane at a preset distance behind the focal point of the focusing lens. S3 takes the observed light intensity pattern as input, constructs a phase estimation optimization problem based on the forward physical model of the coherent laser array, minimizes the mean square error between the physically reconstructed light intensity and the observed light intensity pattern through the gradient descent method of the physical model, and dynamically estimates the phase distribution of the coherent laser array. S4. Based on the target phase distribution corresponding to the target structured light field and the phase distribution estimation results of the coherent laser array, the phase compensation signal of each sub-beam in the coherent laser array is generated, and the corresponding phase modulator is driven to perform phase adjustment. Through multiple iterations, the phase distribution of the coherent laser array is locked to the target phase distribution corresponding to the target structured light field, thereby generating the target structured light field in the far field.

[0011] On the other hand, a system for generating structured light using a laser array phase-locked loop based on physical model gradient descent is provided, for implementing the aforementioned method for generating structured light using a laser array phase-locked loop based on physical model gradient descent, including: A coherent laser array includes a seed laser, a preamplifier, an optical fiber beam splitter, a phase modulator, an optical fiber amplifier, and a collimator array. The seed laser emitted by the seed laser is pre-amplified by the preamplifier and then split into n sub-beams by the optical fiber beam splitter. Each sub-beam has a phase modulator, an optical fiber amplifier, and an adaptive collimator sequentially along its transmission path. Each sub-beam undergoes phase modulation by its corresponding phase modulator, power amplification by its optical fiber amplifier, and collimation by its adaptive collimator. All the adaptive collimators are arranged in the required array configuration to form a collimator array. A light field detection unit is set on the beam transmission path of the coherent laser array. The light field detection unit includes a high reflectivity mirror, a beam splitter, a focusing lens, a first camera, and a second camera. Most of the beam emitted from the coherent laser array is reflected by the high reflectivity mirror. The beam transmitted through the high reflectivity mirror is split into two beams by the beam splitter after passing through the focusing lens and is respectively incident on the first camera and the second camera. The first camera is located at the focal plane of the focusing lens and is used to collect far-field patterns. The second camera is located at a preset distance behind the focusing lens and is used to collect the observed light intensity off the focal plane. The control unit stores the target structured light field and its corresponding target phase distribution. It also receives the observed light intensity from the defocus plane acquired by the second camera. Based on the forward physical model of the coherent laser array, it constructs a phase estimation optimization problem and minimizes the mean square error between the physically reconstructed light intensity and the observed light intensity pattern using the gradient descent method to dynamically estimate the phase distribution of the coherent laser array. Based on the target phase distribution corresponding to the target structured light field and the estimated phase distribution of the coherent laser array, it generates phase compensation signals for each sub-beam in the coherent laser array, drives the corresponding phase modulator to perform phase adjustment, and controls the entire device to iteratively execute light field detection, phase estimation, and phase compensation operations until the phase distribution of the coherent laser array is locked to the target phase distribution corresponding to the target structured light field, thus generating the target structured light field in the far field.

[0012] The present invention has the following technical effects: This invention provides a method for generating structured light using a laser array phase-locked loop based on physical model gradient descent. It requires no additional optical components, such as a reference beam, spatial light modulator, or liquid crystal. Structured light generation and phase locking can be achieved using only a single coherent laser array combined with the physical model gradient descent (PIGD) algorithm, which significantly reduces system complexity and size and improves engineering practicality.

[0013] This invention enables precise locking of a laser array to any target phase distribution, supporting the flexible generation of various structured lights such as Hermit-Gaussian beams, Laguerre-Gaussian beams and their arbitrary superposition states, without the need to design dedicated control strategies for specific structured lights.

[0014] By employing a physical model gradient descent algorithm, rapid phase estimation is achieved through the iterative interaction between forward physical reconstruction and observation data. The single-step phase compensation response time is approximately 2.7ms on the GPU platform, which can be reduced to the nanosecond level after FPGA hardware acceleration, supporting rapid switching of structured light modes.

[0015] Furthermore, to ensure high quality of generated structured light, the gradient of the physical model of the array sub-beams can be scaled by the inverse of its amplitude, effectively avoiding oscillations during phase estimation and compensation, ensuring the stability of phase locking, and achieving a mode purity of over 0.99 for generated structured light.

[0016] The method for generating structured light from a laser array based on gradient descent using a physical model provided by this invention is applicable to coherent laser arrays of different sizes. The larger the array size, the higher the quality of the generated structured light mode, and it can also support the generation of higher-order complex wavefront structured light. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a method for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model, provided in one embodiment. Figure 2 This is a schematic diagram of a system for generating structured light using a laser array phase-locked loop based on physical model gradient descent, as provided in one embodiment. Figure 3 This is a diagram illustrating the generation effects of different types of structured light in one embodiment. Figure 3 (a) is the Hermetic mode HG 21 Phase-locked loop result diagram, Figure 3 (b) is the Laguerre Gaussian model LG 01 Phase-locked loop result diagram, Figure 3 (c) represents the superposition state LG of the Laguerre Gaussian mode. 10 +LG 02 Phase-locked loop result diagram, Figure 3 (d) is the Hermetic mode HG 22 Phase-locked loop result diagram, Figure 3 (e) is the Laguerre Gaussian model LG 02 Phase-locked loop result diagram, Figure 3 (f) represents the superposition state LG of the Laguerre Gaussian mode. 10 +LG 11Phase-locked loop (PLL) result diagram. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Reference Figure 1 One embodiment provides a method for generating structured light using a laser array phase-locked loop based on a physical model gradient descent. This method achieves high-power structured light generation and phase locking through a single laser array. Specifically, it includes the following steps: S1, determine the target structure light field and the corresponding target phase distribution, and set the initial array parameters of the coherent laser array, including sub-beam amplitude, initial phase and array geometric distribution; S2, along the transmission path of the emitted beam of the coherent laser array, the far-field light intensity is collected at the focal plane of the focusing lens through beam splitting and focusing optical paths, and the observed light intensity is collected at the defocus plane at a preset distance behind the focal point of the focusing lens. S3 takes the observed light intensity pattern as input, constructs a phase estimation optimization problem based on the forward physical model of the coherent laser array, minimizes the mean square error between the physically reconstructed light intensity and the observed light intensity pattern through the gradient descent method of the physical model, and dynamically estimates the phase distribution of the coherent laser array. S4. Based on the target phase distribution corresponding to the target structured light field and the phase distribution estimation results of the coherent laser array, the phase compensation signal of each sub-beam in the coherent laser array is generated, and the corresponding phase modulator is driven to perform phase adjustment. Through multiple iterations, the phase distribution of the coherent laser array is locked to the target phase distribution corresponding to the target structured light field, thereby generating the target structured light field in the far field.

[0021] The coherent laser array is formed by a seed laser output from a seed laser, which is then amplified by a preamplifier and split into n sub-beams by an fiber beam splitter. Each sub-beam undergoes phase modulation by a corresponding phase modulator and power amplification by a corresponding fiber amplifier. The sub-beams are then emitted through a collimator array arranged in a predetermined array configuration. Each sub-beam is a linearly polarized Gaussian beam of the fundamental mode with the same wavelength. The array arrangement and size of the coherent laser array are not limited; it can be a circular array, a square array, etc. A larger array size allows for a richer variety of spatial frequency components for synthesis, resulting in higher quality structured light modes with improved purity and fidelity. Examples of coherent laser arrays include 3×3, 5×5, 7×7, or 9×9 square coherent laser arrays. For a square coherent laser array, the coordinate positions of each sub-beam on the emission surface are (…). x j , y j The array is distributed in an equally spaced grid. By supporting scalable array sizes, this invention provides users with a design space that balances system complexity, cost and control difficulty, and the quality of the final output light field, adapting to different scenarios from basic research to industrial high-power applications.

[0022] This invention provides a laser array phase-locking method based on physical model gradient descent. By constructing an accurate forward physical model and implementing closed-loop feedback control, the phase distribution of a laser array can be precisely locked to an arbitrary target phase distribution. This method overcomes the limitations of traditional fixed-mode structured light generation, possessing high flexibility and programmability. The target structured light field of this invention includes, but is not limited to, at least one of Hermitian-Gaussian beams, Laguerre-Gaussian beams, and their arbitrary superposition states. By configuring the corresponding target phase distribution, the method can precisely lock the phase distribution of the laser array to an arbitrary target phase distribution, enabling flexible generation and switching of various structured light modes. Specifically, by using the phase distributions corresponding to typical structured light modes such as Hermitian-Gaussian beams and Laguerre-Gaussian beams and their arbitrary superposition states as the target phase input system, and through the phase estimation and dynamic compensation process of this invention, high-quality structured light of the corresponding mode can be generated in the far field. When a mode switch is required, only the target phase distribution needs to be updated, and the system can quickly iterate and relock the phase, achieving a mode switching speed on the order of milliseconds to microseconds.

[0023] The total optical field of the coherent laser array at the emitting surface is the superposition of the optical fields of all sub-beams, and the expression for the sub-beam optical field is:

[0024] in j Number the sub-beams. j =1,2,......,n, where n is the total number of sub-beams in the coherent laser array;x , y () represents any coordinate position on the launch surface, x j , y j ) is the first j The coordinates of the path beam on the emitting surface. A j For the first j The amplitude of the path beam, ω 0 represents the beam waist width. d For sub-beam aperture, circ For circular domain functions, For the first j Phase of the path beam i The imaginary unit is exp, which represents the exponentiation of e.

[0025] Using the observed light intensity pattern as input, a phase estimation optimization problem is constructed based on the forward physical model of the coherent laser array. The objective expression of the phase estimation optimization problem is:

[0026] in To observe the light intensity pattern, H ( ( ) is the forward physical model of a coherent laser array. The results show the phase distribution estimation of the coherent laser array.

[0027] In S4, the forward physical model of the coherent laser array H ( Derived from Fresnel diffraction theory, it is used to calculate the emission from the emitting surface. z =0 to the defocused observation surface z = L The expression for the light field propagation and the light intensity distribution on the defocused observation surface is:

[0028] in,( u , v Let L be the coordinates of z=L. k Let λ be the wave vector and λ be the laser wavelength. f The focal length of the focusing lens. F ( ) represents the Fourier transform.

[0029] In one embodiment, the physical model gradient descent method employs a stochastic gradient descent optimizer with a learning rate set to 2.0-3.0 and 1-5 iterations in a single phase modulation.

[0030] When it is necessary to switch the target structured light, it is only necessary to update the target phase distribution and repeat the above phase estimation, dynamic phase compensation and locking process to achieve rapid switching between different structured light modes.

[0031] In one embodiment, a system for generating structured light using a laser array phase-locked loop based on physical model gradient descent is provided. This system is used to realize a method for generating structured light using a laser array phase-locked loop based on physical model gradient descent. Specifically, by locking the phase distribution of the laser array to the phase distribution corresponding to the target structured light, arbitrary structured light modes, including Hermit-Gaussian beams, Laguerre-Gaussian beams, and their arbitrary superposition states, are generated.

[0032] Specifically, refer to Figure 2 A system for generating structured light using a laser array phase-locked loop based on physical model gradient descent, as described in one embodiment, includes: The coherent laser array includes a seed laser 1, a preamplifier 2, an optical fiber beam splitter 3, a phase modulator 4, an optical fiber amplifier 5, and a collimator array 6. The seed laser emitted by the seed laser 1 is pre-amplified by the preamplifier 2 and then split into n sub-beams by the optical fiber beam splitter 3. Each sub-beam has a phase modulator 4, an optical fiber amplifier 5, and an adaptive collimator sequentially along its transmission path. Each sub-beam undergoes phase modulation by the corresponding phase modulator 4, power amplification by the optical fiber amplifier 5, and collimation output by the adaptive collimator. All the adaptive collimators are arranged in the required array configuration to form the collimator array 6.

[0033] A light field detection unit is set on the beam transmission path of the coherent laser array. The light field detection unit includes a high reflectivity mirror 7, a focusing lens 8, a beam splitter 9, a first camera 10, and a second camera 11. Most of the beam emitted from the coherent laser array is reflected by the high reflectivity mirror 7. The beam transmitted through the high reflectivity mirror 7 is split into two beams by the beam splitter 9 after passing through the focusing lens 8. These beams are then incident on the first camera 10 and the second camera 11, respectively. The first camera 10 is located at the focal plane of the focusing lens 8 and is used to acquire far-field patterns. The second camera 11 is located at a preset distance behind the focusing lens 8 and is used to acquire the observed light intensity off the focal plane.

[0034] The control unit 12 is used to store the target structured light field and the corresponding target phase distribution, and simultaneously receive the observed light intensity of the defocus plane collected by the second camera. Based on the forward physical model of the coherent laser array, it constructs a phase estimation optimization problem, minimizes the mean square error between the physically reconstructed light intensity and the observed light intensity pattern through the gradient descent method, and dynamically estimates the phase distribution of the coherent laser array. Based on the target phase distribution corresponding to the target structured light field and the phase distribution estimation result of the coherent laser array, it generates the phase compensation signal of each sub-beam in the coherent laser array, drives the corresponding phase modulator to perform phase adjustment, and controls the entire device to iteratively execute the light field detection, phase estimation and phase compensation operations until the phase distribution of the coherent laser array is locked to the target phase distribution corresponding to the target structured light field, and generates the target structured light field in the far field.

[0035] The control unit stores a target phase distribution function library corresponding to various structured light modes, including Hermit-Gaussian beams, Laguerre-Gaussian beams, and their arbitrary superposition states. Based on user selection or external instructions, the corresponding target phase distribution is called from the function library to drive the system to execute a method for generating structured light using laser array phase locking based on physical model gradient descent, thereby realizing the dynamic switching and generation of different structured light modes.

[0036] In one embodiment, the seed laser 1 is a 1064nm linearly polarized seed laser. The fiber beam splitter 3 is a 1×25 fiber beam splitter. The system includes 25 phase modulators 4, 25 fiber amplifiers 5, and a 5×5 square collimator array 6. The adjacent aperture spacing of the collimator array 6 is 25mm, the sub-beam waist width w0=10.24mm, the aperture diameter d=23mm, and the focal length of the focusing lens 8 is f=20m. The first camera 10 is used for focal plane detection, and the second camera 11 is used for defocus plane detection. The second camera 11 is set 0.3m behind the focal point of the focusing lens 8, and the detection resolution is 224×224 pixels. The control unit 12 uses a computer equipped with an NVIDIA GeForce RTX 4070 Laptop GPU to run the PIGD phase estimation algorithm and transmit the phase compensation signal in real time to the phase modulators 4 corresponding to each sub-beam. Based on the system provided in this embodiment, a Laguerre-Gaussian beam LG is generated. 02 For example, the specific implementation steps of generating structured light using a laser array phase-locked loop according to the present invention are as follows: System initialization: Seed laser 1 emits 1064nm linearly polarized laser light, which is amplified by preamplifier 2 and then split into 25 sub-beams by 1×25 fiber beam splitter 3. Each sub-beam passes through phase modulator 4 and fiber amplifier 5, and is then emitted by 5×5 square collimator array 6. Control unit 12 initializes the estimated phase as a random distribution, sets the learning rate of the SGD optimizer to 3.0, and sets the number of PIGD iterations in a single phase modulation to 1.

[0037] Light field detection: The light beam emitted by the collimator array 6 is reflected by the high-reflectivity mirror 7, focused by the lens 8, and then split into two beams by the beam splitter 9. The first camera 10 captures the light intensity pattern on the focal plane for subsequent effect verification. The second camera 11 captures the light intensity pattern on the defocus plane and transmits it to the control unit 12, which is recorded as the observed light intensity pattern. .

[0038] PIGD phase estimation: Control unit 12 calls the pre-stored LG 02 Target phase distribution of the laser beam. Using the observed intensity pattern as input, a forward physical model based on a coherent laser array is established. H ( A phase estimation optimization problem is constructed, and the mean square error between the physically reconstructed light intensity and the observed light intensity pattern is minimized by the gradient descent method of the physical model, so as to dynamically estimate the phase distribution of the coherent laser array.

[0039] In a coherent laser array, the amplitude of each sub-beam A j The difference may exist due to factors such as uneven gain of the fiber amplifier and beam splitting ratio deviation. In standard gradient descent, the magnitude of the gradient of the loss function (i.e., the objective expression of the phase estimation optimization problem) with respect to the phase is usually... A j This is proportional to the amplitude of the sub-beam. This means that sub-beams with larger amplitudes also have larger phase update step sizes, which can easily lead to imbalances in the optimization process across different paths, causing oscillations or even divergence in the phase estimates, affecting the convergence speed and final phase-locking accuracy. To address this problem, this invention minimizes the mean square error between the physically reconstructed light intensity and the observed light intensity pattern using the physical model gradient descent method. When dynamically estimating the phase distribution of the coherent laser array, the mean square error is calculated for the first... j The phase gradient of a sub-beam is proportional to the amplitude of its sub-beam. A j The phase is updated using the inverse scaling of the phase gradient. This method effectively balances the contribution of sub-beams of different amplitudes to the phase update, suppresses oscillations in the phase estimation and dynamic compensation process, and improves the convergence speed and stability of the phase-locked loop.

[0040] Dynamic phase compensation: LG 02The target phase distribution of the beam is used as a phase bias and superimposed with the estimated phase distribution of the coherent laser array to form the phase compensation signal for the 25 sub-beams in the coherent laser array. The control unit 12 transmits the compensation signal to the phase modulator 4 corresponding to each of the 25 sub-beams for phase adjustment. Through continuous iteration of optical field detection, PIGD phase estimation, and dynamic phase compensation, the phase distribution of the coherent laser array is locked to the target phase distribution corresponding to the target structured light field, thereby generating the target structured light field in the far field. When the purity of the structured light mode detected by the focal plane reaches 0.99 or higher, the iteration stops, and the array outputs LG stably in the far field. 02 Structured light.

[0041] Mode switching: When switching from one structured beam to another, simply update the target phase distribution in control unit 12 to the target beam's phase distribution, and repeat the optical field detection, PIGD phase estimation, and dynamic phase compensation. (Refer to...) Figure 3 Here are the generation effect diagrams of different types of structured light obtained using the method of the present invention, wherein... Figure 3 (a) is the Hermetic mode HG 21 Phase-locked loop result diagram, Figure 3 (b) is the Laguerre Gaussian model LG 01 Phase-locked loop result diagram, Figure 3 (c) represents the superposition state LG of the Laguerre Gaussian mode. 10 +LG 02 Phase-locked loop result diagram, Figure 3 (d) is the Hermetic mode HG 22 Phase-locked loop result diagram, Figure 3 (e) is the Laguerre Gaussian model LG 02 Phase-locked loop result diagram, Figure 3 (f) represents the superposition state LG of the Laguerre Gaussian mode. 10 +LG 11 Phase-locked loop (PLL) result diagram.

[0042] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for generating structured light from a laser array using phase-locked loop based on gradient descent of a physical model, characterized in that, include: S1, determine the target structure light field and the corresponding target phase distribution, and set the initial array parameters of the coherent laser array, including sub-beam amplitude, initial phase and array geometric distribution; S2, along the transmission path of the emitted beam of the coherent laser array, the far-field light intensity is collected at the focal plane of the focusing lens through beam splitting and focusing optical paths, and the observed light intensity is collected at the defocus plane at a preset distance behind the focal point of the focusing lens. S3 takes the observed light intensity pattern as input, constructs a phase estimation optimization problem based on the forward physical model of the coherent laser array, minimizes the mean square error between the physically reconstructed light intensity and the observed light intensity pattern through the gradient descent method of the physical model, and dynamically estimates the phase distribution of the coherent laser array. S4. Based on the target phase distribution corresponding to the target structured light field and the phase distribution estimation results of the coherent laser array, the phase compensation signal of each sub-beam in the coherent laser array is generated, and the corresponding phase modulator is driven to perform phase adjustment. Through multiple iterations, the phase distribution of the coherent laser array is locked to the target phase distribution corresponding to the target structured light field, thereby generating the target structured light field in the far field.

2. The method for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model according to claim 1, characterized in that, The coherent laser array is formed by the seed laser output from the seed laser being amplified by a preamplifier and then split into n sub-beams by an optical fiber beam splitter. Each sub-beam is emitted through a collimator array arranged in a set array configuration after passing through a phase modulator and an optical fiber amplifier. Each sub-beam is a linearly polarized fundamental Gaussian beam of the same wavelength.

3. The method for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model according to claim 2, characterized in that, The total optical field of the coherent laser array at the emitting surface is the superposition of the optical fields of all sub-beams, and the expression for the sub-beam optical field is: in j Number the sub-beams. j =1,2,......,n, where n is the total number of sub-beams in the coherent laser array; ( x , y () represents any coordinate position on the launch surface, x j , y j ) is the first j The coordinates of the path beam on the emitting surface. A j For the first j The amplitude of the path beam, ω 0 represents the beam waist width. d For sub-beam aperture, circ For circular domain functions, For the first j Phase of the path beam i The imaginary unit is exp, which represents the exponentiation of e.

4. The method for generating structured light using a laser array phase-locked loop based on gradient descent according to a physical model, as described in claim 2 or 3, is characterized in that... In S3, the objective expression for the phase estimation optimization problem is: in To observe the light intensity pattern, H ( ( ) is the forward physical model of a coherent laser array. The results show the phase distribution estimation of the coherent laser array.

5. The method for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model according to claim 4, characterized in that, In S4, the forward physical model of the coherent laser array H ( Derived from Fresnel diffraction theory, it is used to calculate the emission from the emitting surface. z =0 to the defocused observation surface z = L The expression for the light field propagation and the light intensity distribution on the defocused observation surface is: in,( u , v Let L be the coordinates of z=L. k Let λ be the wave vector and λ be the laser wavelength. f The focal length of the focusing lens. F ( ) represents the Fourier transform.

6. The method for generating structured light using a laser array phase-locked loop based on gradient descent according to claim 1, 2, 3, or 5, characterized in that, The target structured light field is at least one of Hermite-Gaussian beam, Laguerre-Gaussian beam, and any superposition state thereof.

7. The method for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model according to claim 6, characterized in that, The physical model gradient descent method uses a stochastic gradient descent optimizer with a learning rate of 2.0-3.0 and 1-5 iterations in a single phase modulation.

8. A system for generating structured light from a laser array using phase-locked loop based on gradient descent of a physical model, used to implement the method for generating structured light from a laser array using phase-locked loop based on gradient descent of a physical model as described in claim 1, 2, 3, 5, or 7, characterized in that, include: A coherent laser array includes a seed laser, a preamplifier, a fiber beam splitter, a phase modulator, a fiber amplifier, and a collimator array; The seed laser emitted by the seed laser is pre-amplified by a preamplifier and then split into n sub-beams by an optical fiber beam splitter. Each sub-beam has a phase modulator, an optical fiber amplifier, and an adaptive collimator installed sequentially along its transmission path. Each sub-beam is phase-modulated by its corresponding phase modulator, amplified by its optical fiber amplifier, and collimated by its adaptive collimator. All the adaptive collimators are arranged in the required array to form a collimator array. A light field detection unit is set on the beam transmission path of the coherent laser array. The light field detection unit includes a high reflectivity mirror, a beam splitter, a focusing lens, a first camera, and a second camera. Most of the beam emitted from the coherent laser array is reflected by the high reflectivity mirror. The beam transmitted through the high reflectivity mirror is split into two beams by the beam splitter after passing through the focusing lens and is respectively incident on the first camera and the second camera. The first camera is located at the focal plane of the focusing lens and is used to collect far-field patterns. The second camera is located at a preset distance behind the focusing lens and is used to collect the observed light intensity off the focal plane. The control unit stores the target structured light field and its corresponding target phase distribution. It also receives the observed light intensity from the defocus plane acquired by the second camera. Based on the forward physical model of the coherent laser array, it constructs a phase estimation optimization problem and minimizes the mean square error between the physically reconstructed light intensity and the observed light intensity pattern using the gradient descent method to dynamically estimate the phase distribution of the coherent laser array. Based on the target phase distribution corresponding to the target structured light field and the estimated phase distribution of the coherent laser array, it generates phase compensation signals for each sub-beam in the coherent laser array, drives the corresponding phase modulator to perform phase adjustment, and controls the entire device to iteratively execute light field detection, phase estimation, and phase compensation operations until the phase distribution of the coherent laser array is locked to the target phase distribution corresponding to the target structured light field, thus generating the target structured light field in the far field.

9. The system for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model according to claim 8, characterized in that, The seed laser is a 1064nm linearly polarized seed laser.

10. The system for generating structured light using a laser array phase-locked loop based on gradient descent of a physical model according to claim 8, characterized in that, The coherent laser array is a square coherent laser array of 3×3, 5×5, 7×7 or 9×9.

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