Light beam combining system and laser system

Abstract

The embodiment of the invention provides a light beam combining system and a laser system, and the light beam combining system comprises a super lens array which comprises a plurality of super lens structures; the super-surface array comprises a plurality of super-surface structures, the number of the super-surface structures is the same as that of the super-lens structures, and each super-lens structure and one super-surface structure form a light path branch; and the light path beam combining structure is used for combining the light of the plurality of light path branches into one light beam and outputting the light beam. By means of the light beam combining system, continuous phase regulation and control can be achieved, and the light beam combining effect is achieved.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to a photosynthetic beam system and a laser system. Background Art

[0002] Existing diffractive optical devices find it difficult to simultaneously achieve high-precision phase control and low crosstalk, resulting in a deterioration in the beam factor after combining. Summary of the Invention

[0003] The purpose of this application is to provide a photosynthesis system and a laser system that can realize continuous phase control to achieve multi-beam spatial photosynthesis in space and can better maintain the quality of the beam factor.

[0004] In a first aspect, the present invention provides a photosynthetic beam system, comprising: a superlens array, the superlens array comprising a plurality of superlens structures; a metasurface array, the metasurface array comprising a plurality of metasurface structures, wherein the number of the metasurface structures is the same as the number of the superlens structures, wherein each superlens structure and a metasurface structure form an optical path branch; and an optical path combining structure, for combining the light of the plurality of optical path branches into a beam of light for output.

[0005] In the above implementation method, the output laser can first pass through the metalens to realize the collimation of the laser beam, and the collimated laser beam can be deflected after passing through the metasurface structure. Finally, multiple laser beams pass through the optical path combining structure to realize the spatial photosynthesis function.

[0006] In an optional embodiment, the super lens structure includes a plurality of unit cell structures; the unit cell structures of the super lens structure are periodically arranged in a transmission phase arrangement manner.

[0007] In the above implementation, the required phase control can be achieved by periodically arranging the unit cell structure, thereby adjusting the laser beam to a required state and better maintaining the quality of the beam factor.

[0008] In an optional embodiment, the metasurface structure includes a plurality of unit cell structures; the unit cell structures of the metasurface structure are periodically arranged in a rectangular array.

[0009] In an optional embodiment, the unit cell structures within one period of the unit cell structure are arranged with a phase gradient from 0 to 2π.

[0010] In the above implementation, by arranging cylinders of different radii with equal phase gradients within the same period, a phase coverage from 0 to 2π is achieved, and an abnormal deflection phase of the light beam corresponding to the phase gradient arrangement is achieved.

[0011] In the above implementation, continuous control of the light wave phase 0-2π is achieved while combining the laser beams, thereby improving the beam quality of the combined beam and alleviating the power limitation caused by the combined beam.

[0012] In an optional embodiment, the metasurface array includes one or more metasurface structure groups, each group of the metasurface structure groups contains two metasurface structures, the two metasurface structures in each group of the metasurface structure groups are symmetrically arranged, and the phase arrangement of the two metasurface structures in each group of the metasurface structure groups is also symmetrically arranged.

[0013] In the above implementation, the metasurface structures within the group are symmetrically arranged, so that the laser beams passing through the metasurface structures within the group can be deflected in a direction of approaching each other, thereby achieving beam combining more accurately.

[0014] In an optional embodiment, the optical path combining structure includes a plurality of direction adjustment modules, and the number of the direction adjustment modules of the optical path combining structure is the same as the number of metasurface structures in the metasurface array.

[0015] In an optional embodiment, the unit cell structure included in the direction adjustment module is the same as the unit cell structure included in one of the metasurface structures in the metasurface array.

[0016] In an optional embodiment, the period of the super lens structure and the super surface structure is within the range of 700 nm to 900 nm, and the height of the unit cell structure of the super lens structure and the super surface structure is within the range of 700 nm to 900 nm.

[0017] In an optional embodiment, the material of the superlens array, the metasurface array and the optical path beam combining structure is an all-dielectric material.

[0018] In the above implementation, the material of each structure is a full-dielectric material structure, which can reduce loss and improve the efficiency of spatial light beam combining.

[0019] In a second aspect, the present invention provides a laser system comprising: a photosynthetic beam system as described in any one of the aforementioned embodiments and a laser array; wherein the number of lasers contained in the laser array is the same as the number of super lens structures in the super lens array. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 A schematic structural diagram of a photosynthetic beam system provided in an embodiment of the present application; Figure 2 A schematic diagram of the coordination between the photosynthetic beam system and the laser array provided in an embodiment of the present application; Figure 3 A schematic structural diagram of a metalens structure in an example provided in an embodiment of the present application; Figure 4 A schematic structural diagram of a metasurface structure in an example provided in an embodiment of the present application; Figure 5 A schematic diagram of a phase profile obtained when a laser beam provided in an embodiment of the present application is angularly deflected by a metasurface structure; Figure 6 A schematic diagram of the structure of an optical path combining structure in an example provided in an embodiment of the present application; Figure 7 Schematic diagram of the relationship between transmittance and phase at different radii for a square unit cell structure array provided in an embodiment of the present application; Figure 8 A scanning electron microscope image of a metalens fabricated using micro-nanofabrication technology according to an embodiment of the present application; Figure 9 This is a schematic diagram of the structure of the laser system provided in an embodiment of the present application.

[0022] Icons: 100-photocombining system; 110-superlens array; 111-first superlens structure; 112-second superlens structure; 120-supersurface array; 121-first supersurface structure; 122-second supersurface structure; 130-optical path combining structure; 200-laser system; 210-laser array; 211-first laser; 212-second laser. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0024] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0025] In the description of this application, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive products are usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be interpreted as a limitation of this application.

[0026] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0027] With the widespread application of high-power laser technology in optical communications, lidar and other fields, the demand for precise control of laser beams is increasing. As core functional modules, the collimation, deflection and combining of light beams directly affect the output power, accuracy and energy utilization of the system. As a core means to improve the output power and beam quality of high-power laser systems, laser beam combining technology faces the dual challenges of integration and performance. Traditional optical beam combining uses spatial filters, diffraction optical elements or microlenses to achieve multi-beam superposition, which is difficult to meet the requirements of chipization and lightweight. In addition, the filling factor of the microlens array is low, and the thermal expansion of the material at high power is prone to wavefront distortion. In addition, it is difficult for existing diffraction optical devices to achieve high-precision phase control and low crosstalk at the same time, which leads to a deterioration of the beam factor after combining.

[0028] In order to solve the above technical problems, it was proposed to improve the performance of a single link by optimizing optical elements (such as microlens arrays, adaptive mirrors) or introducing partial feedback mechanisms, but the problem of multi-module collaborative control and system-level optimization has not yet been solved.

[0029] Based on the above research, the present application provides a photosynthetic beam system 100 and a laser system 200 that can improve the above problems.

[0030] Figure 1 This is a schematic diagram of the structure of the photosynthetic beam system 100 provided in the embodiment of the present application. Figure 1 As shown, the photosynthesis system 100 includes: a super lens array 110, a metasurface array 120 and a light path combining structure 130.

[0031] The metalens array 110 may include a plurality of metalens structures; the metasurface array 120 may include a plurality of metasurface structures.

[0032] The number of metasurface structures is the same as the number of metalens structures, for example, Figure 1 As shown, the number of the metalens structures in the metalens array 110 is two, and the number of the metasurface structures in the metasurface array 120 is also two; for example, Figure 2 As shown, the number of metalens structures in the metalens array 110 is four, and the number of metasurface structures in the metasurface array 120 is also four. It is understandable that the number of metalens structures in the metalens array 110 can be appropriately selected based on the requirements of the actual use scenario. Figure 1 In the illustrated example, the number of metalens structures in the metalens array 110 is two, and the number of metasurface structures in the metasurface array 120 is also two. In practice, a greater number of metalens structures may be present, and every two metalens structures may form a group and be arranged in parallel.

[0033] Among them, each super lens structure and a super surface structure form an optical path branch. Figure 1 In the example shown, two optical path branches can be formed, which are finally combined into one beam of light through the optical path combining structure 130. Figure 2 In the example shown, four optical branch paths may be formed, which are finally combined into one beam of light through the optical path combining structure 130 .

[0034] Optionally, a unit cell structure may be arranged on the metalens structure and the metasurface structure, and the unit cell structure may be arranged periodically. For example, each unit cell structure may be a cylinder of different radii, and the cylinders may be arranged periodically in a row. Each unit cell structure may be a cube structure of different sizes, or other polarization-independent structures.

[0035] For example, the cylindrical array of the superlens structure can be arranged in a transmission phase arrangement, and the cylindrical array of the metasurface structure can be arranged in a rectangular lattice array.

[0036] The optical path combining structure 130 can be used to combine the light from multiple optical path branches into one beam of light for output.

[0037] Under the action of the superlens structure, the laser beam passing through the superlens can be collimated; under the action of the metasurface structure, the laser beam is deflected at a certain angle; finally, under the action of the optical path combining structure 130, the laser beams passing through each optical path branch are combined into a laser beam.

[0038] In the embodiment of the present application, based on the effects of the super lens structure and the super surface structure, the divergent laser beams can be converged together, and then combined with the optical path combining structure 130, the divergent laser beams can be converged into one laser beam.

[0039] In an optional embodiment, the super lens structure includes a plurality of unit cell structures; the unit cell structures of the super lens structure are periodically arranged in a transmission phase arrangement manner.

[0040] Alternatively, the unit cell structure may be a cylindrical structure. The cylindrical structures of the super lens structure are arranged periodically. Based on actual needs, silicon cylinders with different phase difference values can be selected as a periodic unit cell structure.

[0041] In an optional embodiment, the metasurface structure includes a plurality of unit cell structures; the unit cell structures of the metasurface structure are periodically arranged in a rectangular array.

[0042] Exemplarily, the metasurface structure may be formed by multiple rows forming a period, with the parameters of the unit cell structure in each row being the same. For example, every M rows form a period, and the parameters of the unit cell structure in the first row are the same as the parameters of the unit cell structure in the M+1th row, where M is a positive integer greater than one.

[0043] In this embodiment, the metasurface structure uses silicon cylinders with different phase differences as a periodic unit cell. Based on the generalized refractive index law, a unit cell structure with the desired angular refraction effect can be selected. By varying the unit cell parameters, such as the height and radius, the transmittance and phase can be controlled.

[0044] like Figure 3 As shown, Figure 3 FIG. 1 shows a schematic diagram of a metal lens structure in an example. Figure 3 In the example shown, the unit cell structure within one period of the superlens structure is arranged in a phased pattern with columns having radii of d = 100 nm, d = 155 nm, d = 166 nm, d = 174 nm, d = 182 nm, and d = 198 nm, respectively. The height h is 800 nm. By controlling the phase distribution of the scattered light emitted by the laser, the divergent light wave is adjusted to a plane wavefront, thereby achieving beam collimation.

[0045] In an optional embodiment, the unit cell structures within one period of the unit cell structure of the metasurface structure are arranged with a phase gradient from 0 to 2π.

[0046] In this embodiment, the unit cell structure on the metasurface structure can be a cylindrical array structure. Each cylindrical array structure can be a cylinder with different radii arranged periodically on the substrate. In one example, the radius distribution of a period of cylinders can be d = 100 nm, d = 155 nm, d = 166 nm, d = 174 nm, d = 182 nm, d =198 nm. In this example, every six columns form a period, and the parameters of the unit cell structure of the first column are the same as those of the unit cell structure of the seventh column.

[0047] For example, the cylindrical array structures on the metalens structure and metasurface structure can be formed by using electron beam lithography to draw the structure pattern on the substrate, then using electron beam evaporation to deposit chromium metal as a hard mask material on the nanopattern defined by the lithography, and finally using reactive ion etching technology to dry etch to form a high-aspect ratio nanostructure. The aspect ratio of the high-aspect ratio nanostructure can be in the range of 1:4 to 1:2.

[0048] like Figure 4 As shown, Figure 4 A schematic structural diagram of a metasurface structure in an example is shown. Figure 4 In the example shown, the unit cell structure of the metasurface structure is periodically arranged in a rectangular array. The periodic arrangement of the rectangular array can construct a phase gradient distribution at the subwavelength scale, ensuring the strict consistency of the phase gradient direction and forming a continuous phase change. Figure 4 In the example shown, the first six columns are different nanopillars corresponding to equal-gradient phases from 0 to 2π. Therefore, arranging them in a periodic equal-gradient pattern can achieve beam deflection, change the propagation direction of the incident light wavefront, and achieve high-efficiency beam deflection.

[0049] Optionally, the metasurface array 120 may include one or more metasurface structure groups, each of which includes two metasurface structures, the two metasurface structures in each metasurface structure group are symmetrically arranged, and the phase arrangement of the two metasurface structures in each metasurface structure group is also symmetrically arranged. Exemplarily, the symmetry points of each group of metasurface structures may coincide.

[0050] Optionally, when the metasurface array 120 includes two metasurface structures, the metasurface array 120 may include a first metasurface structure 121 and a second metasurface structure 122 .

[0051] The first super-surface structure 121 is arranged along the first direction, and the cell structures within one period of the cell structure of the first super-surface structure 121 are arranged with a phase gradient of 0 to 2π; the second super-surface structure 122 is arranged along the first direction, and the cell structures within one period of the cell structure of the second super-surface structure 122 are arranged with a phase gradient of 2π to 0.

[0052] The first direction may be different based on the placement of the metasurface structure. Figure 1 In the example shown, the first direction is the direction from top to bottom in the figure.

[0053] by Figure 4 For example, the first metasurface structure 121 may be Figure 4 The second metasurface structure 122 can be arranged in the state shown in FIG. Figure 4 The state shown is rotated 180 degrees.

[0054] like Figure 5 As shown, Figure 5 The phase profile diagram obtained when the laser beam provided by the embodiment of the present application is angularly deflected under the action of the metasurface structure is shown. The X-axis in the diagram represents the position of the metalens structure, and the Z-axis represents the position of the laser beam in space after penetrating the metasurface structure. Figure 5 It can be seen from the figure that the phase of the horizontal wave vector of the laser beam along the positive direction of the Z axis changes after passing through the metasurface structure, thus achieving beam deflection.

[0055] Optionally, when the metasurface array 120 includes four metasurface structures, the metasurface array 120 may include a first metasurface structure, a second metasurface structure, a third metasurface structure and a fourth metasurface structure.

[0056] The first supersurface structure is arranged along the first direction, and the unit cell structure within one period of the unit cell structure of the first supersurface structure is arranged with a phase gradient of 0 to 2π; the second supersurface structure is arranged along the first direction, and the unit cell structure within one period of the unit cell structure of the second supersurface structure is arranged with a phase gradient of 2π to 0. The third supersurface structure is arranged along the second direction, and the unit cell structure within one period of the unit cell structure of the third supersurface structure is arranged with a phase gradient of 0 to 2π; the fourth supersurface structure is arranged along the second direction, and the unit cell structure within one period of the unit cell structure of the fourth supersurface structure is arranged with a phase gradient of 2π to 0. Wherein, the first direction and the second direction can form an angle, for example, the first direction and the second direction can be set perpendicularly. Exemplarily, the first supersurface structure is symmetrically arranged with the second supersurface structure, the third supersurface structure is symmetrically arranged with the fourth supersurface structure, and the first supersurface structure and the second supersurface structure are represented as a first symmetry point, the third supersurface structure and the fourth supersurface structure are represented as a second symmetry point, and the first symmetry point coincides with the second symmetry point.

[0057] Optionally, when the metasurface array 120 includes four metasurface structures, the metasurface array 120 may include a first metasurface structure, a second metasurface structure, a third metasurface structure, a fourth metasurface structure, a fifth metasurface structure and a sixth metasurface structure.

[0058] The first metasurface structure has a phase gradient of 0 to 2π within one period of the unit cell structure of the first metasurface structure along a first direction; the second metasurface structure has a phase gradient of 2π to 0 within one period of the unit cell structure of the second metasurface structure along the first direction. The third metasurface structure has a phase gradient of 0 to 2π within one period of the unit cell structure of the third metasurface structure along a second direction; the fourth metasurface structure has a phase gradient of 2π to 0 within one period of the unit cell structure of the fourth metasurface structure along the second direction. The fifth metasurface structure has a phase gradient of 0 to 2π within one period of the unit cell structure of the fifth metasurface structure along a third direction; and the sixth metasurface structure has a phase gradient of 2π to 0 within one period of the unit cell structure of the sixth metasurface structure along the third direction. The first, second, and third directions may form a certain angle, for example, the first direction and the second direction may form an angle of 60°, and the second direction and the third direction may also form an angle of 60°.

[0059] Exemplarily, the first supersurface structure is symmetrically arranged with the second supersurface structure, the third supersurface structure is symmetrically arranged with the fourth supersurface structure, and the fifth supersurface structure is symmetrically arranged with the sixth supersurface structure. The first supersurface structure and the second supersurface structure are represented as a first symmetrical point, the third supersurface structure and the fourth supersurface structure are represented as a second symmetrical point, and the fifth supersurface structure and the sixth supersurface structure are represented as a third symmetrical point, and the first symmetrical point, the second symmetrical point, and the third symmetrical point coincide.

[0060] In an optional embodiment, the optical path combining structure 130 includes multiple direction adjustment modules. The number of direction adjustment modules in the optical path combining structure is the same as the number of metasurface structures in the metasurface array. Each direction adjustment module corresponds to one of the metasurface structures and is used to adjust the optical path output by its corresponding metasurface structure, thereby combining the optical paths output by each metasurface structure into a single light beam in a single direction through each direction adjustment module.

[0061] like Figure 6 As shown, Figure 6 FIG. 1 shows a schematic diagram of the structure 130 of light path combining in an example. Figure 6 In the example shown, it shows that only two direction adjustment modules are included, wherein the left half block can represent the first direction adjustment module, and the right half block can represent the second direction adjustment module, which is the state after the first direction adjustment module is rotated 180°. Optionally, the optical path combining structure 130 can be formed by splicing two identical metasurface structures adjacent to each other, one of which is rotated 180°, so that the optical path combining structure 130 forms a centrally symmetrical structure. After the laser beams from the symmetrical incident directions (that is, the laser beams output by the first metasurface structure 121 and the second metasurface structure 122) pass through the symmetrical optical path combining structure 130, their phase gradients are adjusted to the same output direction, thereby achieving beam combining.

[0062] Optionally, the first direction adjustment module can be used to adjust the direction of the laser beam passing through the optical path branch where the first metasurface structure 121 is located, and the second direction adjustment module can be used to adjust the direction of the laser beam passing through the optical path branch where the second metasurface structure 122 is located. Exemplarily, the first direction adjustment module and the first metasurface structure 121 can deflect the laser beam in opposite directions, so that after the laser beam passes through the first metasurface structure 121 and the first direction adjustment module in sequence, if the laser beam before passing through the first metasurface structure 121 is in a horizontal direction, the laser beam can remain in a horizontal direction after passing through the first metasurface structure 121 and the first direction adjustment module. Exemplarily, the second direction adjustment module and the second metasurface structure 122 can deflect the laser beam in opposite directions, so that after the laser beam passes through the second metasurface structure 122 and the second direction adjustment module in sequence, if the laser beam before passing through the second metasurface structure 122 is in a horizontal direction, the laser beam can remain in a horizontal direction after passing through the second metasurface structure 122 and the second direction adjustment module.

[0063] In this embodiment, the super lens array 110 may also include a first super lens structure 111 and a second super lens structure 112. The two laser beams passing through the first super lens structure 111 and the second super lens structure 112 may be parallel beams. After the two parallel laser beams pass through the first super surface structure 121 and the second super surface structure 122 respectively, the directions of the laser beams may be deflected. For example, the two laser beams deflected after passing through the first super surface structure 121 and the second super surface structure 122 may converge to the same position of the optical path combining structure 130. For details, please refer to Figure 1 As shown, the laser beam located above the illustration can be deflected downward, and the laser beam located below the illustration can be deflected upward.

[0064] In this embodiment, the first metasurface structure 121 controls the angle of deflection of the laser beam, and the distance between the optical path combining structure 130 and the first metasurface structure 121 can be set based on actual needs. The angle of deflection of the laser beam and the distance between the optical path combining structure 130 and the first metasurface structure 121 can be set in coordination. After the laser beam output by the first metalens structure 111 is deflected by the first metasurface structure 121, it can reach the middle area of the optical path combining structure 130 after passing through the distance between the optical path combining structure 130 and the first metasurface structure 121.

[0065] In this embodiment, the second metasurface structure 122 controls the angle of deflection of the laser beam, and the distance between the optical path combining structure 130 and the second metasurface structure 122 can be set based on actual needs. The angle of deflection of the laser beam and the distance between the optical path combining structure 130 and the second metasurface structure 122 can be set in coordination. After the laser beam output by the second metalens structure 112 is deflected by the second metasurface structure 122, the distance between the optical path combining structure 130 and the second metasurface structure 122 can reach the middle area of the optical path combining structure 130.

[0066] Optionally, the unit cell structure included in the first direction adjustment module is the same as the unit cell structure included in one of the metasurface structures in the metasurface array 120. The unit cell structure included in the second direction adjustment module can be similar to the unit cell structure included in the first direction adjustment module, except that the unit cell structure layout included in the second direction adjustment module is the same as the unit cell structure included in the first direction adjustment module after being rotated 180°.

[0067] exist Figure 2 In the example shown, the optical path combining structure 130 can be formed by projecting the positions of the individual metasurface structures of the metasurface array 120 in space onto a plane. In this example, the structural size of the optical path combining structure 130 is four times that of the metasurface structure.

[0068] Optionally, the period of the super lens structure and the super surface structure is within the range of 700 nm to 900 nm, and the height of the unit cell structure of the super lens structure and the super surface structure is within the range of 700 nm to 900 nm.

[0069] Exemplarily, the period of the super lens structure and the super surface structure can be one of 700nm, 750nm, 800nm, 850nm, 900nm, etc.

[0070] For example, the height of the unit cell structure of the super lens structure and the super surface structure can be one of 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, etc.

[0071] In one embodiment, the period of the metalens structure and the metasurface structure and the height of the unit cell structure can both be 800 nm.

[0072] Optionally, the material of the super lens array 110, the metasurface array 120 and the optical path beam combining structure 130 is all-dielectric material.

[0073] For example, the full dielectric material may be silicon (Si), titanium dioxide (TiO 2 ), gallium nitride (GaN), silicon nitride (SiN), or the like.

[0074] In one example, the photosynthetic beam system 100 may include two identical super-lens structures, two super-surface structures and a symmetrical super-surface structure, which may be composed of a periodic arrangement of a lattice array of cylinders of different radii on a quartz substrate, which may be processed using electron beam exposure, electron beam evaporation, reactive ion etching and other techniques for spatial photosynthesis. The simulation results of the above example show that by selecting silicon cylinders with different phase difference values as a periodic unit cell, the deflection of the light beam can be achieved according to the generalized refractive index law; by changing the height and radius of the silicon cylinder, the transmittance and phase can be controlled. The photosynthetic beam system 100 provided in the embodiment of the present application has high integration, low loss, can achieve continuous phase control, and has good application prospects in integrated optical systems, multi-spectral imaging and intelligent sensing equipment.

[0075] In the embodiments of the present application, in order to select a more suitable metasurface structure, the transmittance and phase relationship of the square unit cell structure array structure at different radii were studied.

[0076] Figure 7 This is a diagram showing the relationship between transmittance and phase of a square lattice array structure at different radii in another example provided by the embodiment of the present application. The numerical calculation was performed using the time-domain finite difference method. At a wavelength of 1550 nm, the transmittance coefficient and phase of the periodic nanocolumns were analyzed by changing the radius of the cylinder from 100 nm to 260 nm. In the calculation, the refractive index of the silicon cylinder is 3.47, the height is fixed at 800 nm, the refractive index of the quartz substrate is 1.45, and the thickness is 2 um. Figure 7 It can be found that by changing the radius of the silicon cylinder (100 ~ 260 nm), the device can obtain a larger transmission amplitude in the full phase range of 0-2π. In the range of cylinder radius of 100~260 nm, the transmittance of the device is maintained above 95%. Figure 7 In the example shown, the abscissa represents the radius, and the ordinates respectively include the transmittance and the phase.

[0077] In the embodiment of the present application, the structure of each device in the photosynthetic beam system 100 provided in the embodiment of the present application can be designed by using the finite-difference time-domain method.

[0078] For example, the regulation of transmittance and phase by changes in device structural parameters can be analyzed, and the phase relationship corresponding to different radii can be obtained by simulation. Specifically, Figure 7As shown. Then, for the rectangular substrate and the cylindrical structure set on the substrate, add the corresponding material refractive indexes for the two, set the simulation area to one unit cell period, add a light source to the substrate, add a point monitor and a surface monitor above the structure, respectively monitoring the phase change and transmittance of the light source after passing through the structure, change the size of the cylindrical radius to perform a parameter sweep, and run the simulation to see the relationship between the radius and the phase through the monitor. Generally, as the radius increases, the phase changes from 0 to 2π.

[0079] In this embodiment, the parameters of each unit cell structure can be designed in combination with the generalized refraction law (also known as Snell's law). According to Snell's law: , to calculate the diffraction angle of the gradient surface ,in and is the refractive index of the surrounding medium on both the transmission and incident sides, represents the incident light angle, represents the vacuum wavelength, represents the phase gradient. Based on Snell's law, cylinders of different radii can be arranged with equal phase gradients within the same period to achieve phase coverage from 0 to 2π, and the anomalous deflection phase of the light beam corresponding to this phase gradient arrangement can be achieved. In this embodiment, the phase distribution of the metalens can be determined based on the divergence angle of the light source. The phase can be discretized and cylinders of corresponding phases can be arranged on the corresponding grid to construct the corresponding metalens.

[0080] Taking the periodic array structure as the research object, a spatial photosynthesis system 100 for a semiconductor laser array 210 can be obtained. The schematic diagram of the entire system is shown in FIG. Figure 1 The unit cell structure of the super lens structure in the super lens array 110 can be composed of nano cylinders, whose lattice constant is consistent with the lattice constant of the simulated cylinder. The lens is gridded with the center at (0, 0). According to the circular lens phase distribution formula: , enter the required focal length and target wavelength to calculate the corresponding grid position on the lens Phase, and the cylinder of the radius corresponding to the phase is placed in the corresponding area. Since the phase arrangement of the lens is arranged according to the phase gradient, the convergence of the light beam can be achieved. After the scattered light source emitted by the laser placed at the focus of the metalens structure passes through the metalens structure at the same time, due to the focusing characteristics of the metalens on the light beam, the scattered light source emitted from the focus will be collimated into parallel light after passing through the metalens, and then focused on the metasurface structure. After the laser beam passes through the metasurface structure, the laser beam is deflected at a certain angle. The metasurface structure is a large-area periodic metasurface with cylinders of equal phase gradients from 0 to 2π arranged as a period. According to Snell's law, cylinders of different radii are arranged according to equal phase gradients in the same period to achieve phase coverage from 0 to 2π, and achieve the abnormal deflection phase of the light beam corresponding to the phase gradient arrangement. In this embodiment, the first metasurface structure 121 can achieve phase coverage from 0 to 2π, achieving the abnormal deflection phase of the laser beam, and the second metasurface structure 122 can be arranged in an opposite equal gradient from 2π to 0 according to the gradient to achieve the opposite angle of beam deflection. After passing through the metasurface structure, the laser beam is focused onto the optical path combining structure 130 with a symmetrical structure. After passing through the optical path combining structure 130, the laser beams of multiple branches are combined into one laser beam, realizing the spatial light combining function.

[0081] In this embodiment, Figure 8 As shown, Figure 8 Scanning electron microscope image of a superlens prepared using micro-nanofabrication technology provided in an embodiment of the present application. Figure 8 In the example shown, only a partial structural schematic diagram of the metalens structure is shown. In the embodiment of the present application, the corresponding GDS layout can be first drawn using Matlab for processing. After the quartz substrate is cleaned, dried, and other processing operations, the designed metasurface nanostructure pattern is processed and drawn on the substrate using electron beam lithography technology. The main process of drawing the nanostructure pattern can include the following steps a1 to c1.

[0082] a1. Spin-coat photoresist (EB200) at 3000 rpm for 1 minute to a film thickness of approximately 200 nm. Bake at 180°C for 90 seconds to remove the solvent.

[0083] The above parameters for spin-coating photoresist are merely exemplary and can be adaptively adjusted based on actual needs. Since the coating speed only affects the thickness of the film, a film thickness of 100nm-250nm can be achieved within a speed range of 2000rpm-5000rpm. In actual use, the appropriate coating speed can be selected based on the actual desired film thickness.

[0084] b1. Exposure: Expose the drawn pattern using an electron beam exposure system with an acceleration voltage of 100 kV and an exposure dose of approximately 200 μC / cm 2 .

[0085] Too small an exposure dose will result in incomplete graphics display, while too large an exposure dose will cause graphics of adjacent cycles to overlap. The exposure doses provided above are only exemplary, and the embodiments of the present application can determine the exposure dose based on actual tests. Optionally, the exposure dose can also be 180 μC / cm 2 -300μC / cm 2 A value in the range.

[0086] c1. Development and fixing: Develop in developer for 60 seconds.

[0087] A shorter exposure time will result in an incomplete display of the exposure pattern, while a longer exposure time will slightly enlarge the pattern. Therefore, you can also observe the development effect in real time and adjust the development time.

[0088] Finally, rinse with clean water and blow dry with N2.

[0089] Electron beam evaporation is used to deposit material onto the photolithographically defined nanopatterns, allowing for subsequent etching to form the metasurface structure. Cr or Ni metal is selected as the hard mask material based on the material's physical and chemical properties. The deposition process can include steps a2 through d2.

[0090] a2. Vacuum pretreatment: The substrate is placed in the electron beam evaporation system and the vacuum degree reaches 10 -6 Torr.

[0091] b2. Material deposition: Control the deposition rate (1-2 A / s) to ensure film uniformity.

[0092] c2. Improve adhesion: Deposit 3-5 nm Ti as an adhesion layer in front of the metal layer.

[0093] d2. Lift-off: Soak the sample in acetone and ultrasonically clean it for 10 minutes to remove any areas without metal. The cleaning effect can be observed; if the metal areas are not removed, increase the ultrasonic cleaning time.

[0094] Each component of the photosynthetic beam system 100 can be manufactured according to the above-mentioned process of steps a1 to c1 and steps a2 to d2.

[0095] In this embodiment, if the number of lasers in the required laser array is large, the deflection angle is mainly determined by the design of the metasurface structure, and is calculated using the generalized refractive index law. The change in the deflection angle can be achieved by changing the phase difference. When the light beam deflection is greater than 30°, there may be a problem of decreased efficiency, which can be solved by optimizing the metasurface structure parameters or using metagratings to achieve large-angle, high-efficiency deflection and beam combining. The arrangement of multiple metasurface structures can be determined by the deflection angle formed on the light path and the distance between the two metasurface structures. The distance can be calculated by the formula L=Dtanθ, where L represents the distance between the metasurface structure and the center of the metasurface array, D represents the distance between the plane where the metasurface array is located and the plane where the light path beam combining structure is located, and θ represents the deflection angle formed by the metasurface structure on the light path.

[0096] The photosynthetic beam combining system 100 obtained based on the above-mentioned design concept and manufacturing process realizes efficient linkage of collimation, deflection and beam combining functions, and can improve the overall accuracy, stability and applicability of light beam control.

[0097] The embodiment of the present application also provides a laser system 200, such as Figure 9 As shown, the laser system 200 may include: a photosynthetic beam system 100 and a laser array 210 .

[0098] exist Figure 9 In the example shown, the laser array 210 includes two lasers. The metalens array 110 also includes two metalens structures, and the metasurface array 120 also includes two metasurface structures, namely a first laser 211 and a second laser 212.

[0099] Optionally, the laser array 210 may also include a larger number of lasers (e.g. Figure 2 As shown), correspondingly, the number of superlens structures in the superlens array 110 and the supersurface structures in the supersurface array 120 can also be more, which is the same as the number of lasers in the laser array 210.

[0100] The number of lasers included in the laser array 210 is the same as the number of super lens structures in the super lens array 110 .

[0101] The photosynthetic beam system 100 provided in the embodiment of the present application can be used in conjunction with the photosynthetic beam system 100 provided in the aforementioned embodiment. For other details of the photosynthetic beam system 100 of this embodiment, please refer to the description in the aforementioned embodiment and will not be repeated here.

[0102] In the embodiment of the present application, a metasurface is combined, and the light wavefront can be manipulated by changing the phase, amplitude or polarization of the light wave on a subwavelength scale. The metasurface structure breaks through the constraints of the diffraction limit on the size of the device, and can achieve smaller scales and higher precision control of light beams. Furthermore, the materials of the superlens structure and the metasurface structure in the embodiment of the present application are all-dielectric materials, which can reduce losses and improve the efficiency of spatial light beam combination, and can achieve multifunctional coordinated control of phase, deflection, energy, etc., breaking through the limitations of traditional optical systems in efficiency, volume and flexibility. The integration of nano-scale coupling and alignment systems on the superlens structure and the metasurface structure can achieve fast and precise alignment of optical fibers and lasers, with high coupling efficiency.

[0103] The foregoing is merely an optional embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures.

[0104] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A photosynthetic beam system, characterized in that: include: A superlens array, comprising a plurality of superlens structures; A metasurface array, comprising a plurality of metasurface structures, wherein the number of the metasurface structures is the same as the number of the superlens structures, and wherein each superlens structure forms an optical path branch with a metasurface structure; The optical path combining structure is used to combine the light from multiple optical path branches into one beam of light for output.

2. The photosynthetic beam system according to claim 1, characterized in that: The super lens structure comprises a plurality of unit cell structures; The unit cell structure of the super lens structure is arranged periodically according to a transmission phase arrangement.

3. The photosynthetic beam system according to claim 1, characterized in that: The metasurface structure comprises a plurality of unit cell structures; The unit cell structure of the metasurface structure is periodically arranged in a rectangular array.

4. The photosynthetic beam system according to claim 3, characterized in that: The unit cell structures within one period of the unit cell structure are arranged with a phase gradient from 0 to 2π.

5. The photosynthetic beam system according to claim 3, characterized in that: The metasurface array includes one or more metasurface structure groups, each of which contains two metasurface structures. The two metasurface structures in each of which are symmetrically arranged, and the phase arrangement of the two metasurface structures in each of which is also symmetrically arranged.

6. The photosynthetic beam system according to claim 1, characterized in that: The optical path combining structure includes a plurality of direction adjustment modules, and the number of the direction adjustment modules of the optical path combining structure is the same as the number of the metasurface structures in the metasurface array.

7. The photosynthetic beam system according to claim 6, wherein: The unit cell structure included in the direction adjustment module is the same as the unit cell structure included in one of the metasurface structures in the metasurface array.

8. The photosynthetic beam system according to any one of claims 1 to 7, characterized in that: The periods of the super lens structure and the super surface structure are within the range of 700 nm to 900 nm, and the heights of the unit cell structures of the super lens structure and the super surface structure are within the range of 700 nm to 900 nm.

9. The photosynthetic beam system according to any one of claims 1 to 7, wherein: The material of the super lens array, the super surface array and the optical path beam combining structure is all-dielectric material.

10. A laser system, characterized in that: include: The photosynthetic beam system and laser array according to any one of claims 1 to 9; The number of lasers included in the laser array is the same as the number of super lens structures in the super lens array.

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