Laser coherent combining array scanning method, apparatus and system

Abstract

The application provides a laser coherent synthesis array scanning method, device and system, which comprises the following steps: determining a far-field scanning angle according to a current scanning position; obtaining a maximum optical path difference that can be borne by a single subarray element in a laser coherent synthesis array under a blazed grating phase control model according to the far-field scanning angle and laser coherent synthesis array parameters; obtaining a required tilt phase to be applied to each subarray element according to the maximum optical path difference that can be borne by the single subarray element; and applying the tilt phase to each subarray element to complete the current scanning. The application can generate an optical path difference in the process of unit beam transmission by introducing a tilt phase control, thereby realizing beam deflection in the far field. The method can realize beam deflection at any angle in the field of view, and the energy of the scanning beam can be further improved and the scanning effect can be optimized by increasing the number of subarray elements.

Description

Technical Field

[0001] This invention relates to the field of fiber laser coherent synthesis technology, and in particular to a laser coherent synthesis array scanning method, apparatus and system. Background Technology

[0002] Currently, fiber laser coherent combining technology is an effective way to obtain high-brightness, high-beam-quality, and high-average-power lasers. Leveraging the advantage of flexible multi-aperture sub-beam control, fiber laser coherent combining technology has been widely applied in high-power laser output, optical field manipulation, and phased array scanning technologies, and is a current research hotspot in the field of laser technology.

[0003] Phased array scanning technology, as a representative application area, has certain development potential in lidar, space optical communication, and multiplexers. In recent years, beam scanning technology has evolved from mechanical beam scanning to optical phased array scanning, enabling dynamic beam scanning in the far field using devices such as liquid crystal phased arrays, silicon-based phased arrays, optical waveguides, and microlens arrays. To further increase the scanning range, improve scanning accuracy, and enhance scanning speed, as well as to achieve far-field beam spot position variations and complex beam shaping, higher demands are placed on phase control models and phase control algorithms.

[0004] Currently, beam scanning methods based on coherent laser coherent combining arrays mostly employ piston phase modulation. Due to the limited scanning angle, this method has limitations when customizing complex optical field patterns; it can only achieve pattern combination by superimposing multiple arrays with the same number of elements and adding beam deflection at different angles. Therefore, employing a more refined phase modulation model to achieve continuous scanning in the far field is of great significance for practical applications. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a laser coherent synthesizing array scanning method, apparatus, and system. By introducing tilt phase control, this invention generates an optical path difference during unit beam transmission, thereby achieving far-field beam deflection. This method can achieve beam deflection at any angle within the field of view, and by increasing the number of sub-elements in the laser coherent synthesizing array, the energy of the scanning beam can be further increased, optimizing the scanning effect.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] On one hand, the present invention provides a laser coherent combining array scanning method, comprising:

[0008] Determine the far-field scanning angle based on the current scanning position;

[0009] Based on the far-field scanning angle and the parameters of the laser coherent synthesizing array, the maximum optical path difference that a single sub-element in the laser coherent synthesizing array can withstand under the blazed grating phase control model is obtained.

[0010] Based on the maximum optical path difference that a single sub-element can withstand, the tilt phase that needs to be applied to each sub-element in the laser coherent synthesis array is obtained;

[0011] A tilt phase is applied to each sub-element in the laser coherent synthesizer array to complete the current scan.

[0012] Furthermore, the maximum optical path difference that a single sub-element in the laser coherent combining array can withstand under the blazed grating phase control model is obtained by the following formula:

[0013] ;

[0014] in For the far-field scanning angle that needs to be achieved, denoted as the diameter of each sub-element in the laser coherent synthesis array.

[0015] Furthermore, the tilt phase required to be applied to each sub-element in the laser coherent combining array for:

[0016] ;

[0017] in λ is the wavelength of the scanning beam.

[0018] Furthermore, the current scanning position described in this invention can be any position within a two-dimensional plane, and the horizontal deflection angle and vertical deflection angle of the current scanning position are respectively... and The required far-field scanning angle is... ;according to , The maximum optical path difference that a single sub-element in a laser coherent synthesizing array can withstand in the horizontal and vertical directions under the blazed grating phase control model was obtained, respectively. and , The diameter of each sub-element in the laser coherent synthesis array;

[0019] The tilt phase required to be applied to each sub-element in the horizontal and vertical directions in a laser coherent combining array and They are respectively:

[0020] ;

[0021] in λ is the wavelength of the scanning beam.

[0022] Furthermore, the laser coherent combining array of the present invention is arranged in a regular hexagonal pattern, which has... n layer, n Greater than or equal to 1; the number of sub-elements in the first layer (innermost layer) of the laser coherent combining array is 1, and the number of sub-elements in each of the remaining layers is... And they are all arranged in a regular hexagonal ring. n Total number of subarray elements in the layer The aperture of the entire laser coherent combining array is... D The aperture parameters of each sub-element are all equal, and the diameter of the sub-element is... d , .

[0023] On the other hand, the present invention provides a laser coherent combining array scanning method, which is a dynamic and continuous scanning method, comprising:

[0024] (S1) Given the light field pattern to be scanned;

[0025] (S2) Determine the far-field scanning angle required for the current scanning position based on the current light field image to be scanned;

[0026] (S3) Based on the far-field scanning angle and the parameters of the laser coherent synthesis array, the maximum optical path difference that a single sub-element in the laser coherent synthesis array can withstand under the blazed grating phase control model is obtained.

[0027] (S4) Based on the maximum optical path difference that a single subarray element can withstand, the tilt phase that needs to be applied to each subarray element in the laser coherent synthesis array is obtained.

[0028] (S5) Apply a tilt phase to each sub-element in the laser coherent synthesis array to complete the current scan, update the current light field image to be scanned, return to step (S2), and repeat continuously until the scanning of the entire light field pattern in step (S1) is completed.

[0029] On the other hand, the present invention provides a laser coherent combining array scanning device, comprising:

[0030] The far-field scanning angle determination unit is used to determine the far-field scanning angle based on the current scanning position;

[0031] The maximum optical path difference acquisition unit is used to obtain the maximum optical path difference that a single sub-element in the laser coherent synthesis array can withstand under the blazed grating phase control model, based on the far-field scanning angle and the parameters of the laser coherent synthesis array.

[0032] The tilt phase calculation unit is used to obtain the tilt phase to be applied to each sub-element in the laser coherent synthesis array based on the maximum optical path difference that a single sub-element can withstand.

[0033] The scanning control unit is used to apply a tilt phase to each sub-element in the laser coherent synthesizer array to complete the current scan.

[0034] On the other hand, the present invention provides a laser coherent combining array scanning system, comprising:

[0035] Amplification module, used for N Generation and amplification of beams in the road unit;

[0036] The output module, including an adaptive fiber collimator array, is used for... N The laser beam coherently combined from the beams of the circuit unit is then output;

[0037] The control module includes a laser coherent synthesizer array scanning control module. The laser coherent synthesizer array scanning control module adopts the above-mentioned laser coherent synthesizer array scanning control method to adjust the tilt angle of each sub-element in the laser coherent synthesizer array to achieve deflection of the far-field beam.

[0038] Furthermore, the output module includes an adaptive fiber collimator array, and the laser coherent synthesizing array scanning control module includes a far-field scanning angle determination unit, a maximum optical path difference acquisition unit, a tilt phase calculation unit, and a scanning control unit. The far-field scanning angle determination unit determines the far-field scanning angle based on the current scanning position; the maximum optical path difference acquisition unit obtains the maximum optical path difference that a single sub-element in the laser coherent synthesizing array can withstand under the blazed grating phase control model based on the far-field scanning angle and the laser coherent synthesizing array parameters; the tilt phase calculation unit obtains the tilt phase required to be applied to each sub-element in the laser coherent synthesizing array based on the maximum optical path difference that a single sub-element can withstand; the scanning control unit feeds back the tilt phase required to be applied to each sub-element to the adaptive fiber collimator corresponding to each sub-element, adjusting the tilt angle of each sub-element in the laser coherent synthesizing array to achieve deflection of the far-field beam.

[0039] Furthermore, the control module also includes a piston phase control module, which is used to extract the piston control quantity of each unit beam to realize piston phase adjustment of each unit beam.

[0040] Furthermore, each unit beam generated in the amplification module corresponds to a cascaded fiber amplifier consisting of a phase modulator and one or more fiber amplifiers, and each unit beam output by the amplification module corresponds to an adaptive fiber collimator in the adaptive fiber collimator array; a low-reflection mirror is used to... NThe laser beam coherently combined from the beams of the path unit is divided into a high-power part and a low-power part. The high-power part is focused by a lens for subsequent laser coherent combining array scanning, while the low-power part is collected by a photodetector and then enters the closed-loop control module.

[0041] Similarly, the laser coherent combining array is arranged in a regular hexagonal pattern, which has n layer, n Greater than or equal to 1; the number of sub-elements in the first layer (innermost layer) of the laser coherent combining array is 1, and the number of sub-elements in each of the remaining layers is... Furthermore, all elements are arranged in a regular hexagonal ring, and the total number of sub-element elements in the laser coherent combining array is [missing information]. The aperture of the entire laser coherent combining array is... D The aperture parameters of each sub-element are all equal, and the diameter of the sub-element is... d , .

[0042] Furthermore, the laser coherent combining array scanning method, apparatus, and system provided by the present invention can be modified by changing the total number of sub-array elements of the laser coherent combining array. N That is, to increase the aperture of the entire array element surface. D This can improve the scanning accuracy of laser coherent combining arrays, among which scanning accuracy... It can also enhance the energy of the far-field light spot.

[0043] Compared with the prior art, the technical effects of the present invention are as follows:

[0044] This invention sets a suitable tilt phase for the sub-elements in a laser coherent combining array. The phase difference caused by the applied tilt phase tilts the wavefront isophase surface, resulting in beam deflection during transmission. Simultaneously, the fiber laser coherent combining array can generate diverse beams, such as vortex beams, cylindrical vector beams, and Bessel beams. Combined with tilt phase modulation, the customized optical field function of the fiber laser coherent combining array can be further expanded, enriching beam scanning types and meeting the needs of different applications. Furthermore, by increasing the number of sub-elements in the laser coherent combining array, the energy of the scanning beam can be further increased, optimizing the scanning effect. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present 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 the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0046] Figure 1 A flowchart of one embodiment;

[0047] Figure 2 This is a schematic diagram of the structure of a laser coherent synthesis array scanning system built in one embodiment;

[0048] Figure 3 This is a diagram showing the arrangement of the laser coherent combining array on the emitting surface in one embodiment;

[0049] Figure 4 This is a schematic diagram of a sawtooth tilt phase control model in one embodiment;

[0050] Figure 5 The diagram shows the near-field phase distribution of a laser coherent combining array comprising 19 sub-elements at different horizontal and vertical deflection angles, and the far-field intensity distribution after Gaussian beam deflection, in one embodiment. (a) is... , (a) is the near-field phase distribution diagram at time; (b) is , Near-field phase distribution diagram at time; (c) is , Near-field phase distribution diagram at time; (d) is , Near-field phase distribution diagram at time; (e) is , The far-field intensity distribution of the Gaussian beam after deflection at time (f) is... , The far-field intensity distribution of the Gaussian beam after deflection at time (g) is shown; , The far-field intensity distribution of the Gaussian beam after deflection at time (h) is... , Far-field intensity distribution of the Gaussian beam after deflection;

[0051] Figure 6 In one embodiment, a laser coherent combining array comprising 19 sub-array elements generates continuous scan patterns of a Gaussian beam in the horizontal, vertical, oblique 45°, and -45° directions, wherein (a) is a continuous scan pattern of the Gaussian beam in the horizontal direction, (b) is a continuous scan pattern of the Gaussian beam in the vertical direction, (c) is a continuous scan pattern of the Gaussian beam in the oblique 45° direction, and (d) is a continuous scan pattern of the Gaussian beam in the oblique -45° direction.

[0052] Figure 7 The letter patterns are customized for far-field scanning of a Gaussian beam generated by a laser coherent synthesis array containing 19 sub-array elements in one embodiment, wherein the far-field scanning pattern shown in (a) is S, the far-field scanning pattern shown in (b) is B, and the far-field scanning pattern shown in (c) is W.

[0053] Figure 8 The diagram shows the near-field phase distribution of a laser coherent combining array comprising 127 sub-elements at different horizontal and vertical deflection angles, and the far-field intensity distribution after Gaussian beam deflection, in one embodiment. (a) is... , (a) is the near-field phase distribution diagram at time; (b) is , Near-field phase distribution diagram at time; (c) is , Near-field phase distribution diagram at time; (d) is , Near-field phase distribution diagram at time; (e) is , The far-field intensity distribution of the Gaussian beam after deflection at time (f) is... , The far-field intensity distribution of the Gaussian beam after deflection at time (g) is shown; , The far-field intensity distribution of the Gaussian beam after deflection at time (h) is... , Far-field intensity distribution of the Gaussian beam after deflection;

[0054] Figure 9 In one embodiment, a laser coherent combining array comprising 127 sub-array elements generates continuous scan patterns of a Gaussian beam in the horizontal, vertical, oblique 45°, and -45° directions, wherein (a) is a continuous scan pattern of the Gaussian beam in the horizontal direction, (b) is a continuous scan pattern of the Gaussian beam in the vertical direction, (c) is a continuous scan pattern of the Gaussian beam in the oblique 45° direction, and (d) is a continuous scan pattern of the Gaussian beam in the oblique -45° direction.

[0055] Figure 10 The letter patterns are customized for far-field scanning of a Gaussian beam generated by a laser coherent synthesis array comprising 127 sub-array elements in one embodiment, wherein the far-field scanning pattern shown in (a) is S, the far-field scanning pattern shown in (b) is B, and the far-field scanning pattern shown in (c) is W. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the spirit of the disclosed content will be clearly explained below with reference to the accompanying drawings and detailed description. Any person skilled in the art, after understanding the embodiments of the present invention, can make changes and modifications based on the techniques taught in the present invention without departing from the spirit and scope of the present invention. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0057] Reference Figure 1One embodiment provides a laser coherent combining array scanning method, comprising:

[0058] Determine the far-field scanning angle based on the current scanning position;

[0059] Based on the far-field scanning angle and the parameters of the laser coherent synthesizing array, the maximum optical path difference that a single sub-element in the laser coherent synthesizing array can withstand under the blazed grating phase control model is obtained.

[0060] Based on the maximum optical path difference that a single sub-element can withstand, the tilt phase that needs to be applied to each sub-element in the laser coherent synthesis array is obtained;

[0061] A tilt phase is applied to each sub-element in the laser coherent synthesizer array to complete the current scan.

[0062] In the above embodiments, the maximum optical path difference that a single sub-element in the laser coherent combining array can withstand under the blazed grating phase control model is obtained by the following formula:

[0063] ;

[0064] in For the far-field scanning angle that needs to be achieved, denoted as the diameter of each sub-element in the laser coherent synthesis array.

[0065] In the above embodiments, the tilt phase required to be applied to each sub-element in the laser coherent combining array for:

[0066] ;

[0067] in λ is the wavelength of the scanning beam.

[0068] It is understood that the current scanning position described in this invention can be any position within a two-dimensional plane, meaning that the scanning method provided by this invention can achieve scanning at any position within a two-dimensional plane. In one embodiment, the horizontal deflection angle and the vertical deflection angle of the current scanning position are respectively... and The required far-field scanning angle is... ;according to , The maximum optical path difference that a single sub-element in a laser coherent synthesizing array can withstand in the horizontal and vertical directions under the blazed grating phase control model was obtained, respectively. and , The diameter of each sub-element in the laser coherent synthesis array;

[0069] The tilt phase required to be applied to each sub-element in the horizontal and vertical directions in a laser coherent combining array and They are respectively:

[0070] ;

[0071] in λ is the wavelength of the scanning beam.

[0072] It should be noted that when the beam deflects to the left... The angle is negative, so it deflects to the right. The angle is positive; it deflects downwards. The angle is negative, so it deflects upwards. The angle is positive. Based on the quantitative relationship between the far-field scanning angle and the tilt phase, the tilt phase is set for the entire array element surface. This phase modulation method belongs to the blazed grating phase control model.

[0073] As a preferred option, the laser coherent combining array is arranged in a regular hexagonal shape, which has the following characteristics: n layer, n Greater than or equal to 1; the number of sub-elements in the first layer (innermost layer) of the laser coherent combining array is 1, and the number of sub-elements in each of the remaining layers is... And they are all arranged in a regular hexagonal ring. n Total number of subarray elements in the layer The aperture of the entire laser coherent combining array is... D The aperture parameters of each sub-element are all equal, and the diameter of the sub-element is... d , . Reference Figure 3 This is a diagram showing the arrangement of a laser coherent synthesis array containing 19 subarray elements.

[0074] One embodiment of the present invention provides a laser coherent combining array scanning method, which is a dynamic and continuous scanning method, comprising:

[0075] (S1) Given the light field pattern to be scanned;

[0076] (S2) Determine the far-field scanning angle required for the current scanning position based on the current light field image to be scanned;

[0077] (S3) Based on the far-field scanning angle and the parameters of the laser coherent synthesis array, the maximum optical path difference that a single sub-element in the laser coherent synthesis array can withstand under the blazed grating phase control model is obtained.

[0078] (S4) Based on the maximum optical path difference that a single subarray element can withstand, the tilt phase that needs to be applied to each subarray element in the laser coherent synthesis array is obtained.

[0079] (S5) Apply a tilt phase to each sub-element in the laser coherent synthesis array to complete the current scan, update the current light field image to be scanned, return to step (S2), and repeat continuously until the scanning of the entire light field pattern in step (S1) is completed.

[0080] It is understood that the implementation methods of the corresponding steps in the above-described dynamic continuous scanning method of laser coherent synthesizing array of the present invention can be implemented by the same methods in the foregoing embodiments, and will not be repeated here.

[0081] The above-mentioned dynamic continuous scanning method of laser coherent synthesis array can realize beam scanning of far-field diffraction screen or customization of specific light field patterns.

[0082] In one embodiment of the present invention, a laser coherent combining array scanning device is provided, comprising:

[0083] The far-field scanning angle determination unit is used to determine the far-field scanning angle based on the current scanning position;

[0084] The maximum optical path difference acquisition unit is used to obtain the maximum optical path difference that a single sub-element in the laser coherent synthesis array can withstand under the blazed grating phase control model, based on the far-field scanning angle and the parameters of the laser coherent synthesis array.

[0085] The tilt phase calculation unit is used to obtain the tilt phase to be applied to each sub-element in the laser coherent synthesis array based on the maximum optical path difference that a single sub-element can withstand.

[0086] The scanning control unit is used to apply a tilt phase to each sub-element in the laser coherent synthesizer array to complete the current scan.

[0087] It is understood that the corresponding functions in the laser coherent synthesizing array scanning device of the present invention can be implemented using the same methods in the foregoing embodiments, and will not be repeated here.

[0088] In one embodiment of the present invention, a laser coherent combining array scanning system is provided, comprising:

[0089] Amplification module, used for N Generation and amplification of beams in the road unit;

[0090] The output module, including an adaptive fiber collimator array, is used for... N The laser beam coherently combined from the beams of the circuit unit is then output;

[0091] The control module includes a laser coherent synthesizer array scanning control module. This module employs a laser coherent synthesizer array scanning control method to adjust the tilt angle of each sub-element in the laser coherent synthesizer array, thereby deflecting the far-field beam. Each laser coherent synthesizer array scanning control module is pre-loaded with a tilt phase control algorithm. The tilt phase control method used in this invention is not limited; various phase control optimization algorithms from existing technologies, such as stochastic parallel gradient descent algorithms, can be employed.

[0092] In a preferred embodiment, the output module includes an adaptive fiber collimator array, and the laser coherent synthesizing array scanning control module includes a far-field scanning angle determination unit, a maximum optical path difference acquisition unit, a tilt phase calculation unit, and a scanning control unit. The far-field scanning angle determination unit determines the far-field scanning angle based on the current scanning position; the maximum optical path difference acquisition unit obtains the maximum optical path difference that a single sub-element in the laser coherent synthesizing array can withstand under the blazed grating phase control model based on the far-field scanning angle and the laser coherent synthesizing array parameters; the tilt phase calculation unit obtains the tilt phase to be applied to each sub-element in the laser coherent synthesizing array based on the maximum optical path difference that a single sub-element can withstand; the scanning control unit feeds back the tilt phase to be applied to each sub-element to the adaptive fiber collimator corresponding to each sub-element, adjusting the tilt angle of each sub-element in the laser coherent synthesizing array to achieve deflection of the far-field beam.

[0093] Reference Figure 2 A laser coherent synthesizing array scanning system constructed according to an embodiment of the present invention includes an amplification module, an output module, and a control module. The amplification module includes a seed source 1, a preamplifier 2, an optical fiber beam splitter 3, a phase modulator 4, and a cascaded optical fiber amplifier 5; the output module includes an adaptive optical fiber collimator array 6, a low-reflection mirror 7, a lens 8, and a far-field receiving screen 9; the control module includes a photodetector 10, a piston phase control module 11, and a laser coherent synthesizing array scanning control module 12.

[0094] Seed source 1 is sequentially connected to preamplifier 2 and fiber beam splitter 3. The laser output from seed source 1 is preamplified and then split into N unit beams by fiber beam splitter 3. Each unit beam passes through phase modulator 4, cascaded fiber amplifier 5, and adaptive fiber collimator array 6. The scanning beam output from adaptive fiber collimator array 6 passes through low-reflection mirror 7. The high-power portion is focused onto far-field receiving screen 9 through lens 8, while the low-power portion is collected by photodetector 10 and converted into an electrical signal, which is then transmitted to piston phase control module 11 and laser coherent combining array scanning control module 12. Piston phase control module 11 extracts the piston phase error of the system, transmits it to phase modulator for phase compensation, and provides piston phase control signal. Laser coherent combining array scanning control module 12 calculates the required tilt control amount for each beam based on the quantitative relationship between far-field scanning angle and tilt phase, and then feeds the tilt control amount back to adaptive fiber collimator array to adjust the tilt angle of each unit optical path, thereby achieving angular deflection of the far-field beam. The phase modulator and adaptive fiber collimator work simultaneously to achieve beam scanning of the far-field diffraction screen or customization of specific light field patterns. Each piston phase control module 11 is pre-loaded with a piston phase control method. The piston phase control method in this invention is not limited; various phase control optimization algorithms from existing technologies, such as single-jitter method, SPGD method, etc., can be used.

[0095] Assuming the laser coherent combining array is arranged in a regular hexagon, it has... n layer, n Greater than or equal to 1; the number of sub-elements in the first layer (innermost layer) of the laser coherent combining array is 1, and the number of sub-elements in each of the remaining layers is... And they are all arranged in a regular hexagonal ring. n Total number of subarray elements in the layer The aperture of the entire laser coherent combining array is... D The aperture parameters of each sub-element are all equal, and the diameter of the sub-element is... d , . Reference Figure 3 This is a diagram showing the arrangement of a laser coherent synthesis array containing 19 subarray elements.

[0096] The working process of the laser coherent combining array scanning control module 12 includes:

[0097] (S1) Given the light field pattern to be scanned;

[0098] (S2) Determine the far-field scanning angle required for the current scanning position based on the current light field image to be scanned;

[0099] (S3) Based on the far-field scanning angle and the parameters of the laser coherent synthesis array, the maximum optical path difference that a single sub-element in the laser coherent synthesis array can withstand under the blazed grating phase control model is obtained.

[0100] (S4) Based on the maximum optical path difference that a single subarray element can withstand, the tilt phase that needs to be applied to each subarray element in the laser coherent synthesis array is obtained.

[0101] (S5) Apply a tilt phase to each sub-element in the laser coherent synthesis array to complete the current scan, update the current light field image to be scanned, return to step (S2), and repeat continuously until the scanning of the entire light field pattern in step (S1) is completed.

[0102] Let the wavelength of the scanning beam output from the emitting surface of the adaptive optics collimator array be λ, and the first... The output amplitude of the beam of the path element is , The Gaussian beam emitted from a single subarray element is in The complex amplitude distribution of the launching surface is expressed as:

[0103] (1)

[0104] In the formula, The sub-beam waist radius, ( , ) represents the position coordinates of a single subarray element, and circ is a circular field function;

[0105] After tilt phase adjustment, the entire laser coherent combining array is The complex amplitude distribution emitted from the launching surface is expressed as:

[0106] (2)

[0107] In the formula, For the number of elements in the subarray, , The horizontal deflection angle, This is the vertical deflection angle;

[0108] The spectrum of the receiving surface is obtained by performing a Fourier transform on equation (2), and then the far field is obtained by performing an inverse Fourier transform. The complex amplitude distribution of the receiving surface is as follows:

[0109] (3)

[0110] Far field The intensity distribution on the receiving surface is as follows:

[0111] (4)

[0112] By changing the total number N of the sub-element in the laser coherent combining array, i.e., increasing the aperture of the entire element surface, D This can improve the scanning accuracy of laser coherent combining arrays, among which scanning accuracy... It can also enhance the energy of the far-field light spot.

[0113] In one embodiment, to more intuitively and comprehensively illustrate the effectiveness of the above scanning method, the following is an example of applying the laser coherent synthesis array scanning method provided by the present invention.

[0114] It should be noted that the examples given in this specification are merely illustrative and are not the only specific implementation examples of the present invention. Those skilled in the art can use the laser coherent synthesis array scanning method provided above by the present invention, based on the illustrative implementation examples provided by the present invention, to realize simulation, practical application or experimentation for different application scenarios.

[0115] In one embodiment: using Figure 2 The laser coherent combining array scanning system structure shown is constructed as follows: Figure 3 The diagram shows a regular hexagonal laser coherent combining array containing 19 sub-elements, where the laser wavelength is 1064 nm and the laser beam waist radius is... Sub-aperture size Array element caliber The distance between the target plane and the launch plane In order to achieve along the far field x Horizontal axis and y Vertical deflection of axis , as well as Direction deflection Four groups were obtained. , The values ​​are respectively , ; , ; , ; , Based on this, the laser coherent combining array scanning method provided by this invention performs dynamic continuous scanning, with reference to... Figure 4 The sawtooth phase control model, which utilizes the quantitative relationship between the tilt phase and the far-field scanning angle, can obtain the tilt control phase distribution for each sub-aperture setting. Figure 5 The images show the near-field phase distribution of a laser coherent synthesis array containing 19 sub-element at different horizontal and vertical deflection angles, as well as the far-field intensity distribution after Gaussian beam deflection. Figure 5 (a) is , (a) is the near-field phase distribution diagram at time; (b) is , Near-field phase distribution diagram at time; (c) is , Near-field phase distribution diagram at time; (d) is , Near-field phase distribution diagram at time; (e) is , The far-field intensity distribution of the Gaussian beam after deflection at time (f) is... , The far-field intensity distribution of the Gaussian beam after deflection at time (g) is shown; , The far-field intensity distribution of the Gaussian beam after deflection at time (h) is... , The far-field intensity distribution diagram after the Gaussian beam is deflected. Figure 5 The positional changes of the light spot in the target plane light field in (e)-(h) are represented by rotations of 0, π / 2, π / 4, and -π / 4 around the center in a two-dimensional plane. As the achievable optical path difference between adjacent sub-elements increases, i.e., the phase difference applied by adjacent sub-elements increases, the scanning angle increases. Therefore, this phase control method can achieve continuous scanning and obtain customized specific light field patterns. Figure 6 Generate continuous scan patterns of a Gaussian beam in the horizontal, vertical, oblique 45°, and -45° directions for a laser coherent combining array containing 19 sub-element elements. Figure 6 (a) is a continuous scan of the Gaussian beam in the horizontal direction, (b) is a continuous scan of the Gaussian beam in the vertical direction, (c) is a continuous scan of the Gaussian beam in the 45° oblique direction, and (d) is a continuous scan of the Gaussian beam in the -45° oblique direction. Figure 7 Customized far-field scanning patterns for generating Gaussian beams for a laser coherent combining array containing 19 sub-elements. Figure 7 The far-field scanning pattern shown in (a) is S, the far-field scanning pattern shown in (b) is B, and the far-field scanning pattern shown in (c) is W.

[0116] In one embodiment: using Figure 2 The laser coherent combining array scanning system structure shown depicts a regular hexagonal laser coherent combining array containing 127 sub-array elements. The arrangement rule of the regular hexagonal laser coherent combining array is... Figure 3 Same. Wherein: the laser wavelength is 1064 nm, and the laser beam waist radius... Sub-aperture size Array element caliber The distance between the target plane and the launch plane In order to achieve along the far field x Horizontal axis andy Vertical deflection of axis , as well as Direction deflection Four groups were obtained. , The values ​​are respectively , ; , ; , ; , Based on this, the quantitative relationship between the tilt phase and the far-field scanning angle can be used to obtain the tilt control phase distribution of each sub-aperture. Figure 8 The diagrams show the near-field phase distribution of a laser coherent synthesis array containing 127 sub-elements at different horizontal and vertical deflection angles, as well as the far-field intensity distribution after Gaussian beam deflection. Figure 8 Figures (a)-(d) show the phase distribution of the emitting surface light field at different deflection angles achieved by a 127-channel laser coherent combining array, thus obtaining the attached... Figure 8 The positional changes of the light spot in the target plane light field in (e)-(h) are manifested as rotations of 0, π / 2, π / 4, and -π / 4 around the center in a two-dimensional plane. As the achievable optical path difference between adjacent sub-elements increases, i.e., the phase difference applied by adjacent sub-elements increases, the scanning angle increases. Therefore, this phase control method can achieve continuous scanning and obtain customized specific light field patterns. Figure 8 (a) is , (a) is the near-field phase distribution diagram at time; (b) is , Near-field phase distribution diagram at time; (c) is , Near-field phase distribution diagram at time; (d) is , Near-field phase distribution diagram at time; (e) is , The far-field intensity distribution of the Gaussian beam after deflection at time (f) is... , The far-field intensity distribution of the Gaussian beam after deflection at time (g) is shown; , The far-field intensity distribution of the Gaussian beam after deflection at time (h) is... , The far-field intensity distribution diagram after the Gaussian beam is deflected. Figure 9 Generate continuous scan patterns of a Gaussian beam in the horizontal, vertical, and oblique 45° and -45° directions for a laser coherent synthesis array containing 127 sub-element elements. Figure 9(a) is a continuous scan of the Gaussian beam in the horizontal direction, (b) is a continuous scan of the Gaussian beam in the vertical direction, (c) is a continuous scan of the Gaussian beam in the 45° oblique direction, and (d) is a continuous scan of the Gaussian beam in the -45° oblique direction. Figure 10 Customized letter patterns for far-field scanning of Gaussian beams generated for a laser coherent synthesis array containing 127 sub-elements. Figure 10 The far-field scanning pattern shown in (a) is S, the far-field scanning pattern shown in (b) is B, and the far-field scanning pattern shown in (c) is W.

[0117] Matters not covered in this invention are common knowledge.

[0118] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0119] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A laser coherent combining array scanning method, characterized in that, include: Determine the far-field scanning angle based on the current scanning position; Based on the far-field scanning angle and the parameters of the laser coherent synthesizing array, the maximum optical path difference that a single sub-element in the laser coherent synthesizing array can withstand under the blazed grating phase control model is obtained. Based on the maximum optical path difference that a single sub-element can withstand, the tilt phase that needs to be applied to each sub-element in the laser coherent synthesis array is obtained; A tilt phase is applied to each sub-element in the laser coherent synthesizer array to complete the current scan.

2. The laser coherent combining array scanning method according to claim 1, characterized in that, The maximum optical path difference that a single sub-element in a laser coherent combining array can withstand under the blazed grating phase control model is obtained by the following formula: θ = arcsin(L / d) Where θ is the desired far-field scanning angle, and d is the diameter of each sub-element in the laser coherent synthesis array.

3. The laser coherent combining array scanning method according to claim 2, characterized in that: The tilt phase required to be applied to each sub-element in a laser coherent combining array for: Where k0 = 2π / λ, and λ is the wavelength of the scanning beam.

4. The laser coherent combining array scanning method according to claim 1, characterized in that: The current scanning position is any position within a two-dimensional plane. The horizontal and vertical deflection angles of the current scanning position are α and β, respectively. The desired far-field scanning angle is... According to α=arcsin(L x / d), β=arcsin(L y / d), respectively, obtain the maximum optical path difference L that a single sub-element in a laser coherent combining array can withstand in the horizontal and vertical directions under the blazed grating phase control model. x and L y d is the diameter of each sub-element in the laser coherent synthesis array; The tilt phase required to be applied to each sub-element in the horizontal and vertical directions in a laser coherent combining array and They are respectively: Where k0 = 2π / λ, and λ is the wavelength of the scanning beam.

5. The laser coherent combining array scanning method according to claim 1, 2, 3, or 4, characterized in that: The laser coherent combining array is arranged in a regular hexagonal pattern and has n layers, where n is greater than or equal to 1. The first layer, i.e., the innermost layer, has 1 subarray element, and each of the remaining layers has 6*(n-1) subarray elements arranged in a regular hexagonal ring. The total number of subarray elements in the n layers is N = 3n. 2 -3n+1; The aperture of the entire laser coherent synthesizing array is D, and the aperture parameters of each sub-element are equal. The diameter of the sub-element is d, and D = d + 2d*(n-1).

6. A laser coherent combining array scanning method, characterized in that, include: (S1) Given the light field pattern to be scanned; (S2) Determine the far-field scanning angle required for the current scanning position based on the current light field image to be scanned; (S3) Based on the far-field scanning angle and the parameters of the laser coherent synthesis array, the maximum optical path difference that a single sub-element in the laser coherent synthesis array can withstand under the blazed grating phase control model is obtained. (S4) Based on the maximum optical path difference that a single subarray element can withstand, the tilt phase that needs to be applied to each subarray element in the laser coherent synthesis array is obtained. (S5) Apply a tilt phase to each sub-element in the laser coherent synthesizer array to complete the current scan, update the current light field image to be scanned, return to step (S2), and repeat continuously until the scanning of the entire light field pattern in step (S1) is completed.

7. A laser coherent combining array scanning device, characterized in that, include: The far-field scanning angle determination unit is used to determine the far-field scanning angle based on the current scanning position; The maximum optical path difference acquisition unit is used to obtain the maximum optical path difference that a single sub-element in the laser coherent synthesis array can withstand under the blazed grating phase control model, based on the far-field scanning angle and the parameters of the laser coherent synthesis array. The tilt phase calculation unit is used to obtain the tilt phase to be applied to each sub-element in the laser coherent synthesis array based on the maximum optical path difference that a single sub-element can withstand. The scanning control unit is used to apply a tilt phase to each sub-element in the laser coherent synthesizer array to complete the current scan.

8. A laser coherent combining array scanning system, characterized in that, include: Amplification module, used for the generation and amplification of N-channel unit beams; The output module includes an adaptive fiber collimator array for outputting the laser after coherent combining of N unit beams; The control module includes a laser coherent synthesizing array scanning control module, which employs the laser coherent synthesizing array scanning control method as described in claim 1, 2, 3, or 4 to adjust the tilt angle of each sub-element in the laser coherent synthesizing array to achieve deflection of the far-field beam.

9. The laser coherent combining array scanning system according to claim 8, characterized in that, The output module includes an adaptive fiber collimator array, and the laser coherent synthesizing array scanning control module includes a far-field scanning angle determination unit, a maximum optical path difference acquisition unit, a tilt phase calculation unit, and a scanning control unit. The far-field scanning angle determination unit determines the far-field scanning angle based on the current scanning position. The maximum optical path difference acquisition unit obtains the maximum optical path difference that a single sub-element in the laser coherent synthesizing array can withstand under the blazed grating phase control model based on the far-field scanning angle and the laser coherent synthesizing array parameters. The tilt phase calculation unit obtains the tilt phase that needs to be applied to each sub-element in the laser coherent synthesizing array based on the maximum optical path difference that a single sub-element can withstand. The scanning control unit feeds back the tilt phase that needs to be applied to each sub-element to the adaptive fiber collimator corresponding to each sub-element, adjusting the tilt angle of each sub-element in the laser coherent synthesizing array to achieve deflection of the far-field beam.

10. The laser coherent combining array scanning system according to claim 9, characterized in that, The control module also includes a piston phase control module, which is used to extract the piston control quantity of each unit beam and realize the piston phase adjustment of each unit beam.

11. The laser coherent combining array scanning system according to claim 9 or 10, characterized in that, Each unit beam generated in the amplification module corresponds to a phase modulator and a cascaded fiber amplifier consisting of one or more fiber amplifiers. Each unit beam output by the amplification module corresponds to an adaptive fiber collimator in the adaptive fiber collimator array. The laser after coherently combining the N unit beams is divided into a high-power part and a low-power part by a low-reflection mirror. The high-power part is focused by a lens for subsequent laser coherent combining array scanning, while the low-power part is collected by a photodetector and then enters the closed-loop control module.

12. The laser coherent combining array scanning system according to claim 11, characterized in that, The laser coherent combining array is arranged in a regular hexagonal pattern, with n layers, where n is greater than or equal to 1. The first layer, the innermost layer, has 1 subarray element, and each of the remaining layers has 6*(n-1) subarray elements arranged in a regular hexagonal ring. The total number of subarray elements in the laser coherent combining array is N = 3n. 2 -3n+1; The aperture of the entire laser coherent synthesizing array is D, and the aperture parameters of each sub-element are equal. The diameter of the sub-element is d, and D = d + 2d*(n-1).

13. The laser coherent combining array scanning system according to claim 12, characterized in that, Let the wavelength of the scanning beam output from the emitter surface of the adaptive optics collimator array be λ, and the output amplitude of the i-th element beam be A. i If i = 1, 2, 3, ..., N, then the complex amplitude distribution of the Gaussian beam emitted from a single subarray element on the xOy emission surface can be expressed as: In the formula, w0 is the sub-beam waist radius, (a i b i ) represents the position coordinates of a single subarray element, and circ represents the circular domain function; After tilt phase adjustment, the complex amplitude distribution of the entire laser coherent combining array emitted from the xOy emitting surface is expressed as: In the formula, N is the number of subarray elements, k0 = 2π / λ, α is the horizontal deflection angle, and β is the vertical deflection angle; After performing a Fourier transform on equation (2), the spectrum of the receiving surface is obtained. Then, an inverse Fourier transform is performed to obtain the complex amplitude distribution of the far-field x'Oy' receiving surface: The intensity distribution at the far-field x'Oy' receiving surface is as follows: I=U2(x',y')×U2(x',y') * (4) By changing the total number N of the subarray elements in the laser coherent synthesizer array, i.e. increasing the aperture D of the entire array element surface, the scanning accuracy of the laser coherent synthesizer array can be improved, where the scanning accuracy δθ = 1.22λ / D, and the far-field spot energy can also be enhanced at the same time.

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