A metasurface structure and method for realizing transverse polarization focusing spectrometry

Abstract

The application provides a kind of to realize transverse polarization focusing spectrometer super surface structure and method, including substrate, also include surface structure, the surface structure is arranged on the substrate;The surface structure is composed of multiple concentric ring arrangement subwavelength structure unit;The subwavelength structure unit carries out polarization independent focusing of incident light beam by transmission phase control, and the subwavelength structure unit carries out polarization dependent spectrometer of incident light beam by geometric phase control.The application can realize polarization dependent beam spectrometer and focusing function, with the advantages of simple structure, high integration, solve the technical problems that present point diffraction plate does not support simultaneous phase shift interferometry and interference fringe contrast is low, make the interference fringe contrast of point diffraction interferometry higher, higher, higher, faster.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical devices, in particular to a metasurface structure and method for realizing transverse polarization focusing and light splitting. BACKGROUND

[0002] With the continuous development of optical technology, as a new type of optical element, metasurface structure has great application potential in the field of light field regulation due to its characteristics of ultra-thinness, planarization and high integration. Metasurface structure is usually composed of an array of sub-wavelength structure units, which can realize precise manipulation of light field by regulating the phase, amplitude and polarization state of electromagnetic wave.

[0003] In the field of optical measurement, point diffraction interferometry as a common-path transverse shearing interferometry technology has the advantages of simple structure and good vibration resistance, and is widely used in optical system wavefront detection. The traditional point diffraction interferometry technology usually uses a pinhole diffraction plate to generate a reference spherical wave, which interferes with the wavefront to be measured to form interference fringes. However, since the pinhole size is usually micron level, which is extremely small compared to the entire detection spot, the light energy passing through the pinhole is small, which makes the interference fringe contrast low, which is not conducive to subsequent data calculation.

[0004] The existing point diffraction interferometry technology usually uses linear carrier demodulation method and phase shift method to calculate the interference fringes. The former has lower calculation accuracy than the phase shift method due to the use of Fourier transform and frequency domain filtering, and the calculation speed is slower, so it is not easy to obtain high frequency information. The latter usually uses wavelength tuning phase shift or mechanical phase shift, which cannot be used for dynamic measurement, limiting its application range.

[0005] Therefore, it is urgent to develop a new type of metasurface structure which can realize polarization-independent focusing and polarization-dependent light splitting functions at the same time, improve the interference fringe contrast, support synchronous phase shift interferometry, thereby improve the calculation accuracy and speed, enhance the high frequency detection capability, and provide a new solution for point diffraction interferometry technology.

[0006] Therefore, the prior art still needs further development. SUMMARY

[0007] The purpose of the present application is to overcome the above technical deficiencies, and to provide a metasurface structure and method for realizing transverse polarization focusing and light splitting, to solve the technical problems of the prior art that the point diffraction plate does not support synchronous phase shift interferometry and the interference fringe contrast is low.

[0008] To achieve the above technical purpose, according to the first aspect of the present application, a metasurface structure for realizing transverse polarization focusing and light splitting is provided, comprising a substrate, and further comprising a surface structure disposed on the substrate.

[0009] The surface structure is composed of a plurality of concentric circularly arranged subwavelength structure units.

[0010] The subwavelength structure units perform polarization-independent focusing of the incident light beam through transmission phase control, and perform polarization-dependent light splitting of the incident light beam through geometric phase control.

[0011] Specifically, the subwavelength structure units in each concentric circle have the same size, shape and rotation angle.

[0012] Specifically, the transmission phase control is realized by adjusting the size and shape of the subwavelength structure units, and the phase distribution of the transmission phase satisfies:

[0013] ;

[0014] wherein, represents the phase value of the incident light beam at the metasurface (x, y), x, y represents the coordinate position on the metasurface, λ represents the wavelength of the incident light beam, f represents the focal length, r represents the radius of the metasurface structure.

[0015] Specifically, the geometric phase control decomposes the incident light beam into left-handed circularly polarized light and right-handed circularly polarized light, and focuses the left-handed circularly polarized light and the right-handed circularly polarized light to two separate focal points in space, respectively.

[0016] Specifically, the two focal points are symmetrically distributed along the horizontal direction, and the spatial separation distance is determined by the tilt angle of the geometric phase control.

[0017] Specifically, the geometric phase control is realized by adjusting the rotation angle of the subwavelength structure units, so that the left-handed circularly polarized light and the right-handed circularly polarized light of the incident light beam produce symmetric tilt phase modulation, and the phase distribution of the geometric phase satisfies:

[0018] ;

[0019] ;

[0020] wherein, represents the phase value of the left-handed circularly polarized light at different positions of the metasurface, represents the phase value of the right-handed circularly polarized light at different positions of the metasurface, and x represents the horizontal coordinate of any point on the metasurface, represents the tilt angle.

[0021] Specifically, the phase modulation of the transverse polarization focusing spectrometer is obtained by superimposing the transmission phase and the geometric phase, and the output phase distribution of the transverse polarization focusing spectrometer satisfies:

[0022] ; ;

[0023] wherein, represents the phase value of the left circularly polarized light at different positions of the metasurface, represents the phase value of the right circularly polarized light at different positions of the metasurface.

[0024] Specifically, the transmission phase control is realized by adjusting the size and shape of the subwavelength structure unit, and specifically includes:

[0025] The concentric ring arrangement mode of the surface structure is based on the phase distribution design of the focusing lens, and different sizes and shapes of the subwavelength structure units on each concentric ring form a subwavelength structure cluster, and the subwavelength structure cluster can realize the control of the wavefront phase in the range of 0-2π.

[0026] Specifically, the geometric phase control is realized by adjusting the rotation angle of the subwavelength structure unit, and specifically includes:

[0027] According to the principle that the geometric phase modulates the phase of left and right circularly polarized light in opposite directions, by changing the rotation angle of the subwavelength structure unit on each concentric ring, the left circularly polarized light is tilted to exit along a first direction, and the right circularly polarized light is tilted to exit along a second direction opposite to the first direction.

[0028] According to a second aspect of the present application, a method for realizing transverse polarization focusing spectrometer is provided, comprising:

[0029] S100, an incident light beam is incident on a metasurface structure of a transverse polarization focusing spectrometer, and polarization-independent focusing is realized by transmission phase control;

[0030] S200, the incident light beam is simultaneously decomposed into left circularly polarized light and right circularly polarized light by geometric phase control;

[0031] S300, the left circularly polarized light and the right circularly polarized light are respectively focused on two separate positions in space to form a transverse shearing interference optical path.

[0032] Advantages:

[0033] The application provides a kind of super surface structure and method for realizing transverse polarization focusing spectrometer, polarization-independent focusing is realized by the transmission phase of subwavelength structure, and polarization-dependent spectrometer is realized by geometric phase simultaneously, wherein transmission phase is realized by adjusting subwavelength structure size, shape, and geometric phase is realized by adjusting subwavelength structure rotation angle.The application realizes transverse polarization focusing spectrometer of incident linearly polarized light, and the focusing effect can improve the interference image fringe contrast of point diffraction, so as to improve the solving accuracy, and the polarization spectrometer effect can introduce polarization phase shift to improve the solving speed, accuracy and high-frequency quantity detection ability.The problems of low fringe contrast and not supporting synchronous phase shift interferometry of existing point diffraction plate are solved, so that the point diffraction interferometry technology has higher fringe contrast, higher solving accuracy and faster solving speed. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is the principle diagram of point diffraction interferometry provided in the specific embodiment of the application;

[0035] Figure 2 is the super surface structure diagram for realizing transverse polarization focusing spectrometer provided in the specific embodiment of the application;

[0036] Figure 3 is the transmission phase focusing principle diagram provided in the specific embodiment of the application;

[0037] Figure 4 is the geometric phase spectrometer principle diagram provided in the specific embodiment of the application;

[0038] Figure 5 is the transverse polarization focusing spectrometer effect diagram provided in the specific embodiment of the application;

[0039] Figure 6 is the flow chart of method for realizing transverse polarization focusing spectrometer provided in the specific embodiment of the application;

[0040] Among them, the reference signs of the above drawings are as follows:

[0041] 1, base; 2, surface structure; 3, subwavelength structure unit; 4, left circularly polarized light; 5, right circularly polarized light; 6, incident light beam; 7, transverse polarization focusing spectrometer super surface structure; 8, focusing lens; 9, point diffraction plate; 10, pinhole; 11, camera. DETAILED DESCRIPTION

[0042] For the personnel in the art to better understand the technical solutions of the present application, the technical solutions of the present application will be described clearly and completely below in combination with the drawings of the present application. Based on the embodiments in the present application, other similar embodiments obtained by the personnel in the art without making creative efforts shall belong to the protection scope of the present application. In addition, the direction words mentioned in the following embodiments, such as “up”, “down”, “left”, “right” and the like are only the directions of the drawings, therefore, the direction words used are used for illustration but not for limiting the present application.

[0043] The present application will be further described below in combination with the drawings and the preferred embodiments.

[0044] Embodiment one

[0045] Please refer to Figure 2 The present embodiment provides a kind of to realize transverse polarization focusing spectrometer super surface structure 7 including substrate 1 and surface structure 2, surface structure 2 is arranged on substrate 1. Surface structure 2 is composed of multiple concentric circularly arranged subwavelength structure units 3. Subwavelength structure unit 3 in each concentric circle has the same size, shape and rotation angle.

[0046] Preferably, subwavelength structure unit 3 in the present embodiment is nanostructure of subwavelength scale, including one of nano column, nano hole or nano fin structure.

[0047] Please refer to Figure 3 In the present embodiment, subwavelength structure unit 3 carries out polarization-independent focusing of incident light beam 6 through transmission phase control, and simultaneously carries out polarization-dependent spectrometer of incident light beam 6 through geometric phase control. Transmission phase control is realized by adjusting the size and shape of subwavelength structure unit 3, which can make the phase distribution of the entire super surface equivalent to focusing lens 8 by placing subwavelength structures of certain size and shape along the radial direction of each concentric circle. The specific transmission phase distribution of the phase distribution can be expressed as:

[0048] ;

[0049] Wherein, represents the phase value of incident light beam 6 at super surface (x, y), x and y represent the coordinate position on super surface, and λ represents the wavelength of incident light beam 6, represents focal length, represents the radius of super surface structure. The above formula describes how to realize the control of transmission phase by adjusting the size and shape of subwavelength structure unit 3, so as to simulate the effect of a focusing lens 8 with a specific phase distribution. Specifically, it ensures that the light waves at different positions on the super surface structure can propagate according to the ideal phase distribution, so as to finally realize the focusing function.

[0050] It can be understood that the concentric ring arrangement of the surface structure 2 in the embodiment is based on the phase distribution design of the focusing lens 8, and the sub-wavelength structure units 3 of different sizes and shapes on each concentric ring form a sub-wavelength structure cluster, which can realize the regulation of the wavefront phase in the range of 0~2π. Since different sizes and shapes of sub-wavelength structures have different regulations on the light wavefront phase, a sub-wavelength structure cluster composed of several sub-wavelength structures of different sizes and shapes can be designed according to this principle, so that it can meet the regulation of the wavefront phase in the range of 0~2π. Then, according to the phase distribution of the focusing lens 8, the sub-wavelength structures in the above-mentioned sub-wavelength structure cluster are arranged at the corresponding phase points, and thus the design of the focusing superlens based on transmission phase can be realized.

[0051] Referring to Figure 4 In the embodiment, the geometric phase regulation decomposes the incident light beam 6 into left circularly polarized light 4 and right circularly polarized light 5, and focuses the left circularly polarized light 4 and the right circularly polarized light 5 at two separate focal points in space, which are symmetrically distributed along the horizontal direction, and the spatial separation distance is determined by the tilt angle a of the geometric phase regulation.

[0052] Further, referring to Figure 4 The geometric phase regulation is realized by adjusting the rotation angle of the sub-wavelength structure unit 3, so that the left circularly polarized light 4 and the right circularly polarized light 5 of the incident light beam 6 produce symmetrical tilt phase modulation, that is, according to the principle that the geometric phase modulates the phase of the left circularly polarized light 4 and the right circularly polarized light 5 in opposite directions, by rotating the angle of the sub-wavelength structure on each ring, a tilt in a certain direction is introduced to the left circularly polarized light 4 (or the right circularly polarized light 5), and at the same time, a tilt in the opposite direction is introduced to the right circularly polarized light 5 (or the left circularly polarized light 4), and thus transverse polarization focusing of incident linearly polarized light can be realized. The phase distribution of the geometric phase of the left circularly polarized light 4 and the right circularly polarized light 5 satisfies:

[0053] ;

[0054] ;

[0055] wherein, represents the phase value of the left circularly polarized light 4 at different positions of the super surface, represents the phase value of the right circularly polarized light 5 at different positions of the super surface, represents the position coordinate of any point on the super surface along the horizontal direction, represents the tilt angle. The above two formulas describe how to achieve the geometric phase control of the left-handed circularly polarized light 4 and the right-handed circularly polarized light 5 by adjusting the rotation angle of the subwavelength structure unit 3. Specifically, the above formulas ensure that the left-handed circularly polarized light 4 and the right-handed circularly polarized light 5 at different positions on the super surface can propagate according to the ideal phase distribution, thereby realizing the function of transverse polarization focusing spectrometry.

[0056] It should be noted here that the control of the geometric phase can be achieved by rotating the super atom structure on each concentric ring by a suitable angle, so that the left-handed circularly polarized light 4 (right-handed circularly polarized light 5) in the incident light beam 6 is tilted to exit in a specific direction, and the right-handed circularly polarized light 5 (left-handed circularly polarized light 4) is tilted to exit in a symmetrical direction.

[0057] It can be understood that, according to the principle that the left and right circularly polarized light phase modulation is opposite to the geometric phase, by changing the rotation angle of the subwavelength structure unit 3 on each concentric ring, the left-handed circularly polarized light 4 is tilted to exit in a first direction, and the right-handed circularly polarized light 5 is tilted to exit in a second direction opposite to the first direction.

[0058] Further, in the present embodiment, the phase modulation of transverse polarization focusing spectrometry is obtained by superimposing the transmission phase and the geometric phase, and the output phase distribution of transverse polarization focusing spectrometry satisfies:

[0059] ;

[0060] ;

[0061] wherein, represents the phase value of the left-handed circularly polarized light 4 at different positions on the super surface, represents the phase value of the right-handed circularly polarized light 5 at different positions on the super surface.

[0062] Referring to Figure 5 , after the incident light beam 6 passes through the super surface structure 7 for realizing transverse polarization focusing spectrometry in the present embodiment, the final polarization focal length spectrometry effect is as shown in Figure 5 , after the incident light beam 6 passes through the super surface structure 7 for realizing transverse polarization focusing spectrometry, the left-handed circularly polarized light 4 and the right-handed circularly polarized light 5 are focused at two points in the x direction, respectively. The focusing effect can improve the interference image fringe contrast of point diffraction, thereby improving the calculation accuracy, and the polarization spectrometry effect can introduce polarization phase shift to improve the calculation speed, accuracy and high-frequency quantity detection capability.

[0063] It should be noted that the embodiment provides a kind of super surface structure for realizing transverse polarization focusing spectrometer, and the super surface structure realizes polarization-independent focusing and polarization-dependent spectrometer function of incident light beam by the synergies of transmission phase and geometric phase.When light beam is incident on the super surface structure, different polarization states of light will be decomposed into left circularly polarized light and right circularly polarized light and be focused on two focus points symmetrically distributed in horizontal direction, to realize the function of transverse polarization focusing spectrometer, and the structure can be widely applied to optical imaging, optical communication, optical information processing and other fields.

[0064] Embodiment two

[0065] Please refer to Figure 6 The embodiment provides a kind of method for realizing transverse polarization focusing spectrometer, adopts the super surface structure 7 for realizing transverse polarization focusing spectrometer described in embodiment one, and the method comprises the following steps:

[0066] S100, incident light beam 6 is incident on the super surface structure 7 for realizing transverse polarization focusing spectrometer, and polarization-independent focusing is realized by transmission phase control.

[0067] Specifically, transmission phase control is realized by adjusting the size and shape of subwavelength structure unit 3, which can be realized by placing subwavelength structure of certain size and shape along the radial direction of each concentric circle to make the phase distribution of the whole super surface equivalent to focusing lens 8, and the specific transmission phase distribution can be expressed as:

[0068] ;

[0069] Wherein, The phase value of incident light beam 6 at super surface (x, y), x, y represents the coordinate position on super surface, and λ represents the wavelength of incident light beam 6, Focal length is represented by f, The radius of super surface structure 2 is represented by r. The above formula describes how to adjust the size and shape of subwavelength structure unit 3 to realize transmission phase control, so as to simulate the effect of focusing lens 8 with specific phase distribution. Specifically, it ensures that light waves at different positions on super surface structure 2 can propagate according to ideal phase distribution, so as to finally realize focusing function.

[0070] In this step, incident light beam 6 is irradiated on the super surface structure 2 composed of substrate 1 and surface structure 2. The surface structure 2 is composed of a plurality of concentric circularly arranged subwavelength structure units 3, and the transmission phase control of these subwavelength structure units 3 is realized by its specific size and shape, so as to realize polarization-independent focusing of incident light beam 6, and transmission phase control follows the phase distribution rule described in embodiment one, so that incident light of different polarization states can be focused.Figure 1 The existing point diffraction interferometry method shown realizes phase shift measurement of point diffraction interferometry technology, which greatly improves the contrast of interference fringes.

[0071] like Figure 1 As shown, existing point diffraction interferometry measurement devices typically include optical components such as a focusing lens 8, a point diffraction plate 9, and a camera 11 arranged sequentially along the optical path. A portion of the test beam (the incident beam 6) is incident through a micrometer-sized pinhole 10 to obtain an ideal reference beam. Interference between this reference beam and the test beam yields interference fringes. Solving these fringes yields the phase of the test beam. Common methods for solving interference fringes include linear carrier demodulation and phase-shifting. The former, due to the use of Fourier transform and frequency domain filtering, has lower accuracy and is slower than the phase-shifting method, and it is also less likely to obtain high-frequency quantities. The latter typically involves wavelength-tuned phase shifting or mechanical phase shifting, neither of which allows for dynamic measurement. Furthermore, since the point diffraction pinhole 10 is typically a micrometer-sized aperture, its fringe contrast is usually low, which is detrimental to calculation. In contrast, the transverse polarization focusing beam splitting method in this embodiment concentrates the reference beam energy, and the beam splitting function achieves synchronous phase shifting, further avoiding the shortcomings of traditional time-shifting methods.

[0072] S200, simultaneously through geometric phase modulation, decomposes the incident beam 6 into left-handed circularly polarized light 4 and right-handed circularly polarized light 5.

[0073] In this step, the subwavelength structural unit 3 in the metasurface structure achieves geometric phase modulation through its rotation angle, decomposing the incident beam 6 into left-handed circularly polarized light 4 and right-handed circularly polarized light 5. This geometric phase modulation causes the left-handed circularly polarized light 4 and the right-handed circularly polarized light 5 to produce symmetrical tilted phase modulation, as described in Embodiment 1, the phase of the left-handed circularly polarized light 4 and the right-handed circularly polarized light 5...

[0074] The cloths respectively satisfy: ;

[0075] ;

[0076] in, This represents the phase value of the left-handed circularly polarized light 4 at different positions on the metasurface. This represents the phase value of right-handed circularly polarized light 5 at different positions on the metasurface. This represents the horizontal coordinates of any point on the hypersurface. represents the tilt angle. The above two formulas describe how to achieve the geometric phase control of the left-handed circularly polarized light 4 and the right-handed circularly polarized light 5 by adjusting the rotation angle of the subwavelength structure unit 3. Specifically, the above formulas ensure that the left-handed and right-handed circularly polarized light 5 at different positions on the metasurface can propagate according to the ideal phase distribution, thereby realizing the function of transverse polarization focusing and light splitting.

[0077] S300, the left-handed circularly polarized light 4 and the right-handed circularly polarized light 5 are focused on two separate positions in space, forming a transverse shearing interference optical path.

[0078] Specifically, the phase modulation of the transverse polarization focusing and light splitting in the embodiment is obtained by superimposing the transmission phase and the geometric phase, and the output phase distribution of the transverse polarization focusing and light splitting satisfies:

[0079]

[0080]

[0081] wherein, represents the phase value of the left-handed circularly polarized light 4 at different positions on the metasurface, represents the phase value of the right-handed circularly polarized light 5 at different positions on the metasurface.

[0082] In this step, after the transmission phase and the geometric phase are cooperatively controlled, the left-handed circularly polarized light 4 is tilted out of the first direction and focused to a focal point in space, while the right-handed circularly polarized light 5 is tilted out of the second direction opposite to the first direction and focused to another focal point. The two focal points are symmetrically distributed along the horizontal direction, and the spatial separation distance is determined by the tilt angle of the geometric phase control. The spatially separated focal points form a transverse shearing interference optical path, which can be used for polarization state analysis and measurement.

[0083] It should be noted that the embodiment provides a method for realizing transverse polarization focusing and light splitting. Through the above steps, the method realizes the functions of polarization-independent focusing and polarization-dependent light splitting of the incident light beam, so that light of different polarization states is decomposed and focused on two focal points symmetrically distributed along the horizontal direction. This method can be widely used in the fields of optical imaging, optical communication, optical information processing, polarization measurement, etc., and is particularly suitable for application scenarios that require simultaneous analysis of the polarization state and spatial distribution of the light beam. In addition, the present application can also be used as a transverse shearing device supporting synchronous phase shifting.

[0084] ​​It should be noted that the terms "first", "second", and the like, in the description and in the claims of the present application are intended to distinguish between similar objects, but are not necessarily intended to describe a particular sequential or chronological order. It is to be understood that the use of such terms is not intended to limit the scope of the embodiments of the present application described herein to the order in which they are discussed. Furthermore, the terms "comprise" and "include", and variations thereof, are intended to cover a non-exclusive inclusion, such that processes, methods, systems, products, or devices that comprise, include, or are otherwise including a list of steps or elements, can include additional steps or elements not expressly listed or inherent to such processes, methods, systems, products, or devices.

[0085] The technical features described above can be combined arbitrarily. Although all possible combinations of the technical features are not described, any combination of the technical features should be considered to be covered by the present specification, as long as there is no contradiction in such a combination.

[0086] The specific embodiments of the present application described above are not to be construed as limiting the scope of the present application. Various other related changes and modifications of the present application can be made in accordance with the technical concept of the present application, and such changes and modifications should be included in the scope of the claims of the present application.

Claims

1. A metasurface structure for achieving lateral polarization focusing and beam splitting, comprising a substrate (1), characterized in that, It also includes a surface structure (2) disposed on the substrate (1); The surface structure (2) is composed of multiple subwavelength structural units (3) arranged in concentric rings; The subwavelength structural unit (3) performs polarization-independent focusing of the incident beam (6) through transmission phase modulation, and the subwavelength structural unit (3) performs polarization-dependent beam splitting of the incident beam (6) through geometric phase modulation. The subwavelength structural units (3) within each concentric ring have the same size, shape, and rotation angle; The transmission phase modulation is achieved by adjusting the size and shape of the subwavelength structural unit (3), and the phase distribution of the transmission phase satisfies: ； in, This represents the phase value of the incident beam (6) at the metasurface (x, y). x, y Indicates the coordinate position on the metasurface. λ Indicates the wavelength of the incident beam (6), f Indicates focal length. r Indicates the radius of the metasurface structure; The geometric phase modulation decomposes the incident beam (6) into left-hand circularly polarized light (4) and right-hand circularly polarized light (5), and focuses the left-hand circularly polarized light (4) and the right-hand circularly polarized light (5) at two separate focal points in space, respectively. The transmission phase modulation is achieved by adjusting the size and shape of the subwavelength structural unit (3), specifically including: The concentric ring arrangement of the surface structure (2) is based on the phase distribution design of the focusing lens (8). Subwavelength structural units (3) of different sizes and shapes on each concentric ring form a subwavelength structural cluster. The subwavelength structural cluster can achieve wavefront phase modulation in the range of 0~2π.

2. The metasurface structure for achieving transverse polarization focusing and beam splitting according to claim 1, characterized in that, The two focal points are symmetrically distributed along the horizontal direction, and their spatial separation distance is determined by the tilt angle controlled by the geometric phase.

3. The metasurface structure for achieving transverse polarization focusing and beam splitting according to claim 1, characterized in that, The geometric phase modulation is achieved by adjusting the rotation angle of the subwavelength structural unit (3), so that the left-hand circularly polarized light (4) and the right-hand circularly polarized light (5) of the incident beam (6) produce symmetrical tilt phase modulation, and the phase distribution of the geometric phase satisfies the following: ； ； in, This represents the phase value of left-handed circularly polarized light (4) at different positions on the metasurface. Let x represent the phase value of right-handed circularly polarized light (5) at different positions on the metasurface, and let x represent the position coordinates of any point on the metasurface along the horizontal direction. Indicates the tilt angle.

4. The metasurface structure for achieving transverse polarization focusing and beam splitting according to claim 3, characterized in that, The phase modulation of the transverse polarization focusing beam splitter is obtained by superimposing the transmission phase and the geometric phase, and the output phase distribution of the transverse polarization focusing beam splitter satisfies: ； ； in, This represents the phase value of left-handed circularly polarized light (4) at different positions on the metasurface. This represents the phase value of right-hand circularly polarized light (5) at different positions on the metasurface.

5. The metasurface structure for achieving transverse polarization focusing and beam splitting according to claim 3, characterized in that, The geometric phase modulation is achieved by adjusting the rotation angle of the subwavelength structural unit (3), specifically including: Based on the principle that the geometric phase modulates the left and right circularly polarized light phases in opposite ways, by changing the rotation angle of the subwavelength structural unit (3) on each concentric ring, the left circularly polarized light (4) is made to be emitted at an angle along the first direction, while the right circularly polarized light (5) is made to be emitted at an angle along the second direction opposite to the first direction.

6. A method for achieving transverse polarization focusing and beam splitting, characterized in that, The method employs the metasurface structure for achieving lateral polarization focusing and beam splitting as described in any one of claims 1-5, and includes: S100, the incident beam (6) is incident on the transversely polarized focusing beam splitting metasurface structure, and polarization-independent focusing is achieved through transmission phase modulation; S200, and simultaneously decompose the incident beam (6) into left-hand circularly polarized light (4) and right-hand circularly polarized light (5) through geometric phase modulation. S300, left-handed circularly polarized light (4) and right-handed circularly polarized light (5) are focused at two separate positions in space to form a transverse shearing interference optical path.

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