Polarization selective absorber based on elliptical structure

Abstract

The invention discloses a polarization selective absorber based on an elliptical structure, which relates to the technical field of optical devices and comprises a substrate layer, a low-loss dielectric layer and a metal surface pattern array layer which are fixedly arranged in sequence from bottom to top, the metal surface pattern array layer comprises a plurality of elliptical unit bodies which are arranged in an array mode, and gaps are formed between the elliptical unit bodies. The structure is simple, processing is easy, and polarization selective broadband absorption can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of optical devices, and in particular to a polarization selective absorber based on an elliptical structure. Background Art

[0002] Polarization-sensitive absorbers can collect not only intensity and phase information, but also polarization information. Polarization imaging, which uses polarization information for detection, is a new detection technology that combines polarization measurement with image processing. By measuring the polarization degree and angle information of target radiation and reflection, useful information can be distinguished from a complex natural background. Compared with traditional intensity images and infrared thermal images, infrared polarization imaging can not only effectively identify low-contrast targets that traditional intensity imaging cannot or is difficult to distinguish, but is also less affected by the external environment and can highlight the contour features of the target object.

[0003] Most traditional polarization-sensitive broadband absorbers adopt a composite surface structure design strategy. The high cost and complicated process routes brought about by their complex surface structures limit their advantages in space remote sensing, mineral exploration, infrared detection, medical diagnosis, camouflage identification and other fields that traditional technologies do not have.

[0004] Therefore, it is necessary to provide a polarization selective absorber which has a simple structure, is easy to process and can achieve polarization selective broadband absorption. Summary of the invention

[0005] The purpose of the present invention is to provide a polarization selective absorber based on an elliptical structure to solve the problems existing in the above-mentioned prior art, to make the structure simple and easy to process, and to achieve polarization selective broadband absorption.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a polarization selective absorber based on an elliptical structure, comprising a substrate layer, a low-loss dielectric layer and a metal surface pattern array layer which are fixedly arranged in sequence from bottom to top; the metal surface pattern array layer comprises a plurality of elliptical unit bodies arranged in an array, and there is a spacing between each of the elliptical unit bodies.

[0008] Preferably, there are a plurality of elliptical unit bodies in the first direction and a plurality of elliptical unit bodies in the second direction, the first direction is perpendicular to the second direction; the elliptical unit bodies have the same size, the elliptical unit bodies in the first direction are arranged in the same direction and in parallel, and the elliptical unit bodies in the second direction are arranged in the same direction and in parallel; or the elliptical unit bodies have the same size, the major axes of the elliptical unit bodies in the first direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies, and the major axes of the elliptical unit bodies in the second direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies. The elliptical units of the two sizes are arranged in a staggered manner, the elliptical units in the first direction are arranged in the same direction and in parallel, and the elliptical units in the second direction are arranged in the same direction and in parallel; or the elliptical units of the two sizes are arranged in a staggered manner, the major axis of each elliptical unit in the first direction is in the same cross arrangement as the major axis of the adjacent elliptical unit, and the major axis of each elliptical unit in the second direction is in the same cross arrangement as the major axis of the adjacent elliptical unit.

[0009] Preferably, the minor axis length of the elliptical unit body is 0.5 μm to 2 μm, and the major axis length is 1 μm to 7 μm.

[0010] Preferably, the distance between two adjacent elliptical unit bodies is 1 μm to 7 μm.

[0011] Preferably, the thickness of the base layer is not less than 100 nm; the thickness of the low-loss dielectric layer is 100 nm to 600 nm; and the thickness of the metal surface pattern array layer is 200 nm to 400 nm.

[0012] Preferably, the base layer is made of metal or non-metal material.

[0013] Preferably, the base layer is formed by introducing argon gas into a high vacuum chamber, applying a direct current power supply to generate a magnetic field and bombarding a target with generated argon ions to cause sputtering.

[0014] Preferably, the low-loss dielectric layer is formed by sputtering by applying radio frequency power in an argon environment.

[0015] Preferably, the metal surface pattern array layer is prepared by coating and drying the ultraviolet positive resist on the low-loss dielectric layer; and using an MLA maskless photolithography machine to perform laser direct writing on the coated ultraviolet positive resist according to the drawing to produce a template for the surface pattern, and after development with a corresponding developer, a metal film is deposited by magnetron sputtering and the result is obtained after de-bonding by a lift-off process.

[0016] Preferably, the base layer is made of copper.

[0017] Compared with the prior art, the present invention has achieved the following technical effects:

[0018] The polarization selective absorber based on the elliptical structure provided by the present invention simplifies the shape of the unit cell by adopting an elliptical unit cell structure, avoids complex contour modification while maintaining the basic shape of the ellipse, and reduces high-precision alignment and complex etching steps in processing; the elliptical structure has natural geometric anisotropy, and is different from a circular or square structure. When light is incident in different polarization directions, its interaction with the elliptical unit cell is significantly different. The charge distribution and surface plasma resonance mode induced on the metal surface by light polarized parallel to the major axis of the ellipse are significantly different from those induced by light polarized parallel to the minor axis, so that the absorber can accurately distinguish light in different polarization states and realize efficient polarization selection function; the device realizes polarization-selective broadband absorption with a simple surface graphic structure, and its simple surface structure makes it easy to process, low cost, large-area production and easy integration.

[0019] Furthermore, the arrangement of the surface structure can be the same-size ellipse arrangement in the same direction, the different-direction arrangement, the same-direction arrangement of ellipses of compound sizes, and the different-direction arrangement of ellipses of compound sizes to achieve a variety of composite polarization selective absorption.

[0020] Furthermore, such a size range design further highlights the inherent geometric anisotropy of the elliptical structure. The significant length difference between the major axis and the minor axis makes the surface plasmon resonance effect induced when light with different polarization directions interacts with the elliptical unit body completely different. When the polarization direction of the light is parallel to the major axis, the plasma is distributed and oscillated along the major axis, producing stronger resonant absorption than the polarized light parallel to the minor axis, thereby accurately distinguishing different polarization states and enhancing the polarization selection characteristics of the absorber. Ellipses of different sizes correspond to different resonant frequencies. When the lengths of the major and minor axes vary within a specified range, they can excite a variety of localized surface plasmon resonances and gap plasmon resonance modes. Ellipses with a smaller minor axis and a moderate major axis may correspond to high-frequency resonances. Ellipses with a longer major axis and a slightly larger minor axis are more likely to excite low-frequency resonances. The numerous resonant frequencies are intertwined and complemented, effectively broadening the absorption bandwidth of target bands such as long-wave infrared.

[0021] Furthermore, the existence of the spacing prevents the strong electromagnetic coupling interference caused by the adjacent elliptical unit cells being too close. When the spacing between the units is too small, their electromagnetic fields will overlap and interfere with each other, disrupting the originally independent and regular surface plasma resonance mode, making it difficult to accurately control the polarization absorption characteristics. Maintaining a spacing of 1μm-7μm can ensure that each elliptical unit cell can stably absorb specific polarized light based on its own major and minor axis sizes, thereby maintaining clear polarization selection performance.

[0022] Furthermore, the thickness of the substrate layer is not less than 100nm. A sufficiently thick substrate layer can provide stable and solid physical support for the low-loss dielectric layer and the metal surface pattern array layer above, and avoid deformation and displacement of the upper fine structure due to external force impact, vibration and other factors during subsequent processing, assembly and actual use, thereby ensuring the structural integrity of the absorber and maintaining stable performance. The thickness is in the range of 100nm-600nm. The dielectric layer can effectively regulate the propagation path of light in the absorber. When light passes through the low-loss dielectric layer, it will repeatedly shuttle between the dielectric and the upper and lower layers due to refraction and reflection. The appropriate thickness prolongs the interaction time between the light and the metal surface pattern array layer, prompting more light energy to be coupled into the metal layer for absorption conversion, thereby enhancing the overall absorption effect and helping to achieve broadband absorption. The thickness of the metal layer is set at 200nm-400nm, which is sufficient to support a strong surface plasma resonance effect. A metal layer that is too thin is difficult to maintain stable plasma oscillations, affecting the selective absorption of light with different polarizations. This thickness range can ensure that the free electrons in the metal can efficiently form resonance under light excitation, thereby achieving precise polarization selection and absorption.

[0023] Furthermore, the basic principle for selecting copper is that compared with other materials, copper material has lower loss and can significantly weaken the polarization-independent propagation plasmon resonance, thereby enhancing the dominant role of localized plasmon resonance in absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of a structure in which elliptical unit cells of the same size are arranged in the same direction in a polarization selective absorber based on an elliptical structure provided by the present invention;

[0026] Figure 2 for Figure 1 Absorption spectra of the structure in two polarization modes;

[0027] Figure 3 for Figure 1 Extinction ratio parameter diagram under the structure;

[0028] Figure 4 A schematic diagram of the structure of anisotropic arrangement of elliptical unit cells of complex sizes in the polarization selective absorber based on an elliptical structure provided by the present invention;

[0029] Figure 5 for Figure 4 Absorption spectra of the structure in two polarization modes.

[0030] In the figure: 1-base layer; 2-low-loss dielectric layer; 3-elliptical unit body; 4-large elliptical structure; 5-small elliptical structure. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The purpose of the present invention is to provide a polarization selective absorber based on an elliptical structure to solve the problems existing in the prior art, to make the structure simple and easy to process, and to achieve polarization selective broadband absorption.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Embodiment 1

[0035] This embodiment provides a polarization selective absorber based on an elliptical structure, such as Figure 1 to Figure 5 As shown, it includes a base layer 1, a low-loss dielectric layer 2 and a metal surface pattern array layer which are fixedly arranged in sequence from bottom to top; the metal surface pattern array layer includes a plurality of elliptical unit bodies 3 arranged in an array, and there is a spacing between each elliptical unit body 3.

[0036] By adopting the elliptical unit cell 3 structure, the unit cell shape is simplified, and while maintaining the basic shape of the ellipse, complex contour modification is avoided, reducing high-precision alignment and complex etching steps in processing; the elliptical structure has natural geometric anisotropy. Unlike the circular or square structure, when light is incident in different polarization directions, its interaction with the elliptical unit cell 3 is significantly different. The charge distribution and surface plasmon resonance mode induced on the metal surface by light polarized parallel to the long axis of the ellipse are significantly different from those induced by light polarized parallel to the short axis, so that the absorber can accurately distinguish light in different polarization states and realize efficient polarization selection function; the device realizes polarization-selective broadband absorption with a simple surface graphic structure, and its simple surface structure makes it easy to process, low cost, large-area production and easy integration.

[0037] Among them, the relevant setting instructions for the base layer 1 are:

[0038] In the optional solutions of this embodiment, it is more preferred that the material of the base layer 1 is metal or non-metal material.

[0039] Specifically, the material of the base layer 1 includes but is not limited to metals such as copper and aluminum or non-metal materials.

[0040] In the optional scheme of this embodiment, it is more preferred that the material of the substrate layer 1 is copper. The basic principle of selecting copper is that compared with other materials, copper material has a smaller loss, which can significantly weaken the polarization-independent propagation plasmon resonance, thereby enhancing the dominant role of localized plasmon resonance in absorption.

[0041] In the optional scheme of this embodiment, it is more preferred that the base layer 1 is formed by introducing argon gas into a high vacuum chamber, applying a direct current power supply to generate a magnetic field and bombarding a target with generated argon ions to cause sputtering.

[0042] Among them, the relevant setting description of the low-loss dielectric layer 2 is as follows:

[0043] In the optional scheme of this embodiment, it is more preferred that the low-loss dielectric layer 2 is formed by sputtering by applying radio frequency power in an argon environment.

[0044] Specifically, the material of the low-loss dielectric layer 2 includes, but is not limited to, aluminum oxide, silicon, germanium and the like.

[0045] Among them, the relevant settings for the metal surface pattern array layer are as follows:

[0046] Specifically, the metal of the metal surface pattern array layer includes, but is not limited to, titanium, tungsten, gold, silver and other materials.

[0047] In the optional scheme of this embodiment, it is more preferred that the metal surface pattern array layer is formed by evenly coating and drying the ultraviolet positive resist on the low-loss dielectric layer 2; and using an MLA maskless photolithography machine to perform laser direct writing on the evenly coated ultraviolet positive resist according to the drawing to produce a template for the surface pattern, and after development with a corresponding developer, a metal film is plated by magnetron sputtering, and the result is obtained after de-coating by a lift-off process.

[0048] Specifically, the elliptical unit cells 3 on the metal surface pattern array layer have the same size and same direction arrangement, the same size and different direction arrangement, the composite size and the composite size and different direction arrangement, so as to realize a variety of composite polarization selective absorption, as follows:

[0049] In the optional scheme of this embodiment, it is more preferred that Figure 1 and Figure 4 As shown, there are a plurality of elliptical unit bodies 3 in the first direction, and a plurality of elliptical unit bodies 3 in the second direction, the first direction is perpendicular to the second direction; the elliptical unit bodies 3 have the same size, the elliptical unit bodies 3 in the first direction are arranged in the same direction and in parallel, and the elliptical unit bodies 3 in the second direction are arranged in the same direction and in parallel; or the elliptical unit bodies 3 have the same size, the major axes of the elliptical unit bodies 3 in the first direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies 3, and the major axes of the elliptical unit bodies 3 in the second direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies 3 or having two sizes of elliptical unit bodies 3, the two sizes of elliptical unit bodies 3 are staggered, the elliptical unit bodies 3 in the first direction are arranged in the same direction and in parallel, and the elliptical unit bodies 3 in the second direction are arranged in the same direction and in parallel; or having two sizes of elliptical unit bodies 3, the two sizes of elliptical unit bodies 3 are staggered, the major axis of each elliptical unit body 3 in the first direction is in the same cross arrangement as the major axis of the adjacent elliptical unit body 3, and the major axis of each elliptical unit body 3 in the second direction is in the same cross arrangement as the major axis of the adjacent elliptical unit body 3. The arrangement of the surface structure can be the same size ellipse in the same direction, in an opposite direction, compound size ellipse in the same direction, and compound size ellipse in an opposite direction to achieve a variety of composite polarization selective absorption.

[0050] In the optional scheme of this embodiment, it is more preferred that the minor axis length of the elliptical unit body 3 is 0.5μm to 2μm, and the major axis length is 1μm to 7μm. Such a size range design further highlights the inherent geometric anisotropy of the elliptical structure. The significant length difference between the major axis and the minor axis makes the surface plasmon resonance effect induced when the light of different polarization directions interacts with the elliptical unit body 3 completely different. When the polarization direction of the light is parallel to the major axis, the plasma is distributed and oscillated along the major axis, and compared with the polarized light parallel to the minor axis, a stronger resonant absorption is produced, thereby accurately distinguishing different polarization states and strengthening the polarization selection characteristics of the absorber; ellipses of different sizes correspond to different resonant frequencies. When the length of the major and minor axes changes within a specified range, a rich variety of localized surface plasmon resonances and gap plasmon resonance modes can be excited. Ellipses with smaller minor axes and moderate major axes may correspond to high-frequency resonances; ellipses with longer major axes and slightly larger minor axes are easy to excite low-frequency resonances. Many resonant frequencies are intertwined and complemented with each other, effectively broadening the absorption bandwidth of target bands such as long-wave infrared.

[0051] In the optional scheme of this embodiment, it is more preferred that the spacing between two adjacent elliptical unit cells 3 is 1μm to 7μm. The existence of the spacing prevents the strong electromagnetic coupling interference caused by the adjacent elliptical unit cells 3 being too close. When the unit cell spacing is too small, their electromagnetic fields will overlap and interfere with each other, causing the originally independent and regular surface plasma resonance mode to be disrupted, making it difficult to accurately control the polarization absorption characteristics. Maintaining a spacing of 1μm-7μm can ensure that each elliptical unit cell 3 can stably absorb specific polarized light according to its own major axis and minor axis size, and maintain clear polarization selection performance.

[0052] Among them, about other related settings description:

[0053] In the optional scheme of this embodiment, it is more preferred that the thickness of the base layer 1 is not less than 100 nm; the thickness of the low-loss dielectric layer 2 is 100 nm to 600 nm; and the thickness of the metal surface pattern array layer is 200 nm to 400 nm. The thickness of the base layer 1 is not less than 100nm. A sufficiently thick base layer 1 can provide stable and solid physical support for the low-loss dielectric layer 2 and the metal surface pattern array layer above. In the subsequent processing, assembly and actual use, it can avoid deformation and displacement of the upper fine structure due to external force impact, vibration and other factors, ensure the structural integrity of the absorber, and maintain stable performance. The thickness is in the range of 100nm-600nm. The dielectric layer can effectively regulate the propagation path of light in the absorber. When light passes through the low-loss dielectric layer 2, it will repeatedly shuttle between the dielectric and the upper and lower layers due to refraction and reflection. The appropriate thickness prolongs the interaction time between the light and the metal surface pattern array layer, prompting more light energy to be coupled into the metal layer for absorption conversion, strengthening the overall absorption effect, and helping to achieve broadband absorption. The thickness of the metal layer is set at 200nm-400nm. This thickness is sufficient to support a strong surface plasma resonance effect. A metal layer that is too thin is difficult to maintain stable plasma oscillations, affecting the selective absorption of light with different polarizations. This thickness range can ensure that the free electrons in the metal can efficiently form resonance under light excitation, thereby achieving precise polarization selection and absorption.

[0054] Specifically, the polarization selective absorber based on the elliptical structure of the present embodiment has a strong polarization sensitivity to long-wave to very long-wave infrared polarized light (there are few studies on polarization-sensitive broadband absorbers that play a role in atmospheric windows such as mid-wave infrared (3-5 μm), long-wave infrared (8-14 μm) and very long-wave bands (14-30 μm), among which the research on long-wave to very long-wave infrared plays an important role in security monitoring, environmental monitoring, aerospace and other fields), and has a high extinction ratio; its simple surface structure enables it to be tunable in the design to adapt to various forms of polarization detection to cope with various complex situations in actual use scenarios. In practical applications, such as security monitoring, environmental monitoring, aerospace and other fields, polarization-sensitive long-wave infrared broadband absorbers with simple structures and easy processing have great application prospects. The polarization selective absorber based on the elliptical structure of the present embodiment has the advantages of simple preparation process, low cost, high repeatability, large-scale production and low maintenance cost, and has great application prospects in space remote sensing, mineral exploration, infrared detection, medical diagnosis, camouflage recognition and other fields.

[0055] Specific implementation case 1: Based on the same-direction arrangement of elliptical units 3 of the same size

[0056] See also Figure 1 As shown, it includes: a base layer 1, a low-loss dielectric layer 2 and a metal surface pattern array layer.

[0057] The general magnetron sputtering method is to introduce argon gas into a high vacuum chamber, apply a DC power supply to generate a magnetic field, and use the generated argon ions to bombard the copper target to sputter and form a uniform and dense 100-nanometer thick metal copper film layer.

[0058] Similarly, by using magnetron sputtering, a 400-nanometer-thick low-loss dielectric layer 2 is formed in sequence by applying radio frequency power in an argon environment.

[0059] On the basis of the above, ultraviolet positive resist is used for leveling and drying, and the thickness of the resist is controlled between 300 nanometers and 2 microns.

[0060] Use the MLA maskless lithography machine to perform laser direct writing on the UV positive resist evenly coated in the previous step according to the drawing to produce a template for the surface pattern.

[0061] After developing with a corresponding developer, a metal film with a thickness of 300 nanometers is deposited again by magnetron sputtering.

[0062] Finally, the lift-off process was used to remove the glue and obtain a metal single-size elliptical surface pattern array with a thickness of 300 nanometers. Its major axis was 1.6 microns, the minor axis was 0.5 microns, the spacing between the ellipses in the minor axis direction was 0.5 microns, and the spacing between the ellipses in the major axis direction was 1.6 microns.

[0063] The absorption spectra of the polarization selective absorber based on the elliptical structure in the present embodiment in two polarization modes are shown in FIG. Figure 2 As shown in the figure, in the transverse magnetic wave mode, the highest absorption peak of the device appears at 13.3 microns, with an absorption rate of 99.9%. The average absorption rate of the device in the long-wave to very long-wave infrared band from 12 microns to 16 microns can reach 75.3%. In the transverse electric wave mode, the average absorption rate of the device in the long-wave to very long-wave infrared band from 12 microns to 16 microns is only 4.5%.

[0064] The extinction ratio parameter diagram of the polarization selective absorber based on the elliptical structure of this embodiment is as follows Figure 3 As shown, the extinction ratio of the device in the long-wave to very long-wave band of 12 to 16 microns is greater than 10, and the average extinction ratio is 16.5, wherein the extinction ratio peak occurs at a wavelength of 13.5 microns, and the extinction ratio is 21.0.

[0065] Specific implementation case 2: Anisotropic arrangement of elliptical unit cells 3 based on composite size

[0066] See also Figure 4 As shown, it comprises: a base layer 1, a low-loss dielectric layer 2 and a metal surface pattern array layer;

[0067] Using magnetron sputtering, argon gas is introduced into a high vacuum chamber, and a DC power supply is applied to generate a magnetic field to bombard the copper target with the generated argon ions, sputtering to form a uniform and dense 100-nanometer thick metal copper film layer.

[0068] Similarly, by using magnetron sputtering, a 400-nanometer-thick low-loss dielectric layer 2 is formed in sequence by applying radio frequency power in an argon environment.

[0069] On the basis of the above, ultraviolet positive resist is used for leveling and drying, and the thickness of the resist is controlled between 300 nanometers and 2 microns.

[0070] Use the MLA maskless lithography machine to perform laser direct writing on the UV positive resist evenly coated in the previous step according to the drawing to produce a template for the surface pattern.

[0071] After developing with a corresponding developer, a metal film with a thickness of 300 nanometers is deposited again by magnetron sputtering.

[0072] Finally, the lift-off process was used to remove the glue and obtain a metal single-size elliptical surface graphic array with a thickness of 300 nanometers, in which the large elliptical structure 4 in the elliptical array has a major axis of 2.1 microns and a minor axis of 1 micron; the small elliptical structure 5 in the elliptical array has a major axis of 1.7 microns and a minor axis of 1 micron. The spacing between ellipses in the direction of the minor axis is 1.4 microns, and the spacing between ellipses in the direction of the major axis is 0.65 microns.

[0073] The absorption spectra of the polarization selective absorber based on the elliptical structure in the present embodiment in two polarization modes are shown in FIG. Figure 5 As shown, in the transverse electric wave mode, the highest absorption peak of the device appears at 12.5 microns, and the absorption rate is 99.1%. In the transverse magnetic wave mode, the highest absorption peak of the device appears at 14.9 microns, and the absorption rate is 96.7%.

[0074] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A polarization selective absorber based on an elliptical structure, characterized in that: It includes a base layer, a low-loss dielectric layer and a metal surface pattern array layer which are fixedly arranged in sequence from bottom to top; The metal surface pattern array layer includes a plurality of elliptical unit bodies arranged in an array, and there is a spacing between each of the elliptical unit bodies.

2. The polarization selective absorber based on an elliptical structure according to claim 1, characterized in that: There are a plurality of the elliptical unit bodies in a first direction and a plurality of the elliptical unit bodies in a second direction, and the first direction is perpendicular to the second direction; The elliptical unit bodies have the same size, the elliptical unit bodies in the first direction are arranged in the same direction and in parallel, and the elliptical unit bodies in the second direction are arranged in the same direction and in parallel; Or the elliptical unit bodies have the same size, the major axes of the elliptical unit bodies in the first direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies, and the major axes of the elliptical unit bodies in the second direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies; Or the elliptical unit bodies have two sizes, and the elliptical unit bodies of the two sizes are arranged in a staggered manner, the elliptical unit bodies in the first direction are arranged in the same direction and in parallel, and the elliptical unit bodies in the second direction are arranged in the same direction and in parallel; Or the elliptical unit bodies have two sizes, and the elliptical unit bodies of the two sizes are arranged in a staggered manner, and the major axes of each of the elliptical unit bodies in the first direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies, and the major axes of each of the elliptical unit bodies in the second direction are arranged in the same cross shape as the major axes of the adjacent elliptical unit bodies.

3. The polarization selective absorber based on elliptical structure according to claim 1, characterized in that: The minor axis length of the elliptical unit body is 0.5 μm to 2 μm, and the major axis length is 1 μm to 7 μm.

4. The polarization selective absorber based on an elliptical structure according to claim 3, characterized in that: The distance between two adjacent elliptical unit bodies is 1 μm to 7 μm.

5. The polarization selective absorber based on elliptical structure according to claim 1, characterized in that: The thickness of the base layer is not less than 100 nm; The thickness of the low-loss dielectric layer is 100nm to 600nm; The thickness of the metal surface pattern array layer is 200nm-400nm.

6. The polarization selective absorber based on elliptical structure according to claim 1, characterized in that: The material of the base layer is metal or non-metal material.

7. The polarization selective absorber based on an elliptical structure according to claim 1, characterized in that: The base layer is formed by introducing argon gas into a high vacuum chamber, applying a direct current power supply to generate a magnetic field and bombarding a target with generated argon ions to cause sputtering.

8. The polarization selective absorber based on an elliptical structure according to claim 1, characterized in that: The low-loss dielectric layer is formed by sputtering by applying radio frequency power in an argon environment.

9. The polarization selective absorber based on an elliptical structure according to claim 1, characterized in that: The metal surface pattern array layer is formed by coating and drying the low-loss dielectric layer with an ultraviolet positive resist; The MLA maskless lithography machine is used to laser direct write the uniform UV positive photoresist according to the drawing to produce a template of the surface pattern. After being developed with the corresponding developer, a metal film is plated by magnetron sputtering and the result is obtained after the photoresist is removed by the lift-off process.

10. The polarization selective absorber based on elliptical structure according to claim 6, characterized in that: The base layer is made of copper.

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