Multifunctional far-infrared metamaterial absorber

Abstract

The utility model relates to far infrared metamaterial absorber technical field, specifically disclose a multifunctional far infrared metamaterial absorber, including a plurality of periodic array arrangement's metamaterial unit, the metamaterial unit is for the laminated structure, from top to bottom includes successively: dirac half metal layer, graphene layer, dielectric layer, metal reflection layer, the dirac half metal layer is rudder -shaped, including center hollow cylinder's square structure, cylinder structure, four rectangle structure, the cylinder structure is located the outside of square structure, square structure, cylinder structure concentric arrangement, four rectangle structures evenly distribute in the outside of square structure, four rectangle structures respectively with square structure side vertical intersection. The far infrared metamaterial absorber of the application has tunable multi-peak absorption characteristic, and has wideband and narrowband dynamic switching ability.

Description

Technical Field

[0001] This utility model belongs to the technical field of far-infrared metamaterial absorbers, and specifically relates to a multifunctional far-infrared metamaterial absorber. Background Technology

[0002] The far-infrared band has unique advantages such as low energy, wide bandwidth, high penetration and high resolution, and has great potential for application in food monitoring, disease diagnosis, biosensing, non-destructive testing and environmental monitoring.

[0003] However, the photon energy characteristics of metamaterials result in poor compatibility and weak response with traditional noble metal materials, limiting device design and technological innovation. To overcome this obstacle, metamaterial structures have been introduced into the research of far-infrared absorbers. Metamaterial absorbers offer flexible and thinner structural designs, strong absorption, and a significant response to far-infrared waves. Although metamaterial far-infrared absorbers have significant advantages in far-infrared wave absorption, they still face some challenges in practical applications. Because existing metamaterial absorbers typically have limited functionality, only capable of absorbing a single frequency, applying them to complex environments requires the introduction of a series of metamaterial absorbers with different response frequencies, bands, or waveforms, leading to excessive system complexity and reduced integration. To address these issues, researchers have developed metamaterial absorbers with various functions, including tunable absorbers, multi-narrowband absorbers, and wide-narrowband convertible absorbers. While these absorbers enhance the functionality of metasurface units to some extent, most metamaterial absorbers currently only achieve perfect dual-band absorption, with a few achieving perfect six-band absorption. Currently, the number of absorption bands in metamaterial absorbers rarely exceeds six, making simultaneous perfect absorption of multiple bands still quite difficult. Therefore, developing a multifunctional far-infrared metamaterial absorber is of great significance. Utility Model Content

[0004] The purpose of this invention is to provide a multifunctional far-infrared metamaterial absorber that possesses advantages such as perfect absorption across multiple narrow bands, dynamic adjustability, and wide / narrow band switching. The specific technical solution is as follows:

[0005] A multifunctional far-infrared metamaterial absorber includes several metamaterial units arranged in a periodic array. The metamaterial units are stacked structures, including, from top to bottom: a Dirac semimetal layer 4, a graphene layer 3, a dielectric layer 2, and a metal reflective layer 1. The Dirac semimetal layer 4 is rudder-shaped and includes a square structure 41 with a hollow cylinder at the center, a cylindrical structure 42, and four rectangular structures 43. The cylindrical structure 42 is disposed outside the square structure 41. The square structure 41 and the cylindrical structure 42 are concentrically arranged. The four rectangular structures 43 are evenly distributed outside the square structure 41. The four rectangular structures 43 intersect the side of the square structure 41 perpendicularly, with one end contacting the side of the square structure 41 and the other end embedded in the cylindrical structure 42, extending to the edge of the metamaterial unit.

[0006] Preferably, in the far-infrared metamaterial absorber described above, the metamaterial unit has a periodic size of 20μm*20μm; the square structure 41 has a side length of 7μm, a thickness of 3.4μm, a hollow cylinder diameter of 2μm, and a height of 3.4μm; the cylindrical structure 42 has an inner radius of 8μm, an outer radius of 9μm, and a thickness of 3.4μm; and the rectangular structure 43 has a width of 1μm and a thickness of 3.4μm.

[0007] Preferably, in the far-infrared metamaterial absorber described above, the graphene layer 3 is a single layer of graphene with a thickness of 0.34 nm and a length and width of 20 μm.

[0008] Preferably, in the far-infrared metamaterial absorber described above, the dielectric layer 2 has a thickness of 4.6 μm and a length and width of 20 μm.

[0009] Preferably, in the far-infrared metamaterial absorber described above, the dielectric layer 2 is made of titanium dioxide.

[0010] Preferably, in the far-infrared metamaterial absorber described above, the metal reflective layer 1 has a thickness of 0.2 μm and a length and width of 20 μm.

[0011] Preferably, in the far-infrared metamaterial absorber described above, the metal reflective layer 1 is made of gold.

[0012] Compared with existing technologies, this utility model has the following beneficial effects:

[0013] The far-infrared metamaterial absorber of this invention consists of a Dirac half-metal layer, a graphene layer, a dielectric layer, and a metal reflective layer. Through optimization of the design of each layer and the patterned structure of the Dirac half-metal layer, perfect absorption across eight narrowbands in the 8-15 THz frequency range is achieved. Furthermore, by altering the Fermi level of the Dirac half-metal, an average absorption rate of 91.21% can be achieved in the 11.2532-14.7864 THz frequency range, demonstrating wide-band / narrow-band switching capability. Moreover, tuning to multiple narrowbands can be achieved by adjusting the Fermi level of either the graphene or the Dirac half-metal, exhibiting dynamic tunability. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0015] Figure 1 This is a schematic diagram of the metamaterial unit structure of the far-infrared metamaterial absorber of this utility model.

[0016] Figure 2 This is a top view of the metamaterial unit structure of the far-infrared metamaterial absorber of this utility model.

[0017] Figure 3 This is a front view of the metamaterial unit structure of the far-infrared metamaterial absorber of this utility model.

[0018] Figure 4 The above is a comparison of the absorption spectra of the far-infrared metamaterial absorber in this embodiment of the invention when the Fermi level of graphene is 0.4 eV, and the Fermi levels of the Dirac half-metal are 0.5 eV and 0.07 eV, respectively.

[0019] Figure 5 The absorption spectrum of the far-infrared metamaterial absorber in this embodiment of the invention is shown as a function of the Dirac half-metal Fermi level when the Fermi level of graphene is 0.4 eV.

[0020] Figure 6 The absorption spectrum of the far-infrared metamaterial absorber in this embodiment of the invention shows the change in the graphene Fermi level when the Dirac half-metal Fermi level is 0.5 eV.

[0021] Figure 7 The graph shows the variation of the resonant frequency of the far-infrared metamaterial absorber with the BDS Fermi level in an embodiment of the present invention.

[0022] Figure 8 The graph shows the variation of the resonant frequency of the far-infrared metamaterial absorber with the Fermi level of graphene in an embodiment of the present invention.

[0023] Explanation of key figure labels:

[0024] 1-Metallic reflective layer, 2-Dielectric layer, 3-Graphene layer, 4-Dirac half-metal layer, 41-Square structure, 42-Cylindrical structure, 43-Four rectangular structures. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] In the description of this utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "top surface", "bottom surface", "inner", "outer", "inner side", "outer side", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0027] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If the terms "first," "second," and "third" are used in the description, they are for descriptive purposes and to distinguish technical features, and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The embodiments of this utility model will now be described based on its overall structure.

[0029] Example 1

[0030] A dynamically tunable multi-narrowband far-infrared metamaterial absorber comprises several metamaterial units arranged in a periodic array, such as... Figures 1-3 As shown, the periodic size is Px=Py=20μm, and the metamaterial unit is a stacked structure, consisting of a metal reflective layer 1, a dielectric layer 2, a graphene layer 3, and a Dirac half-metal layer 4 from bottom to top.

[0031] The Dirac semi-metallic layer 1 is shaped like a ship's wheel and consists of a square structure 41 with a hollow cylinder at the center, a cylindrical structure 42, and four rectangular structures 43. The square structure 41 and the cylindrical structure 42 are arranged concentrically, with the cylindrical structure 42 located outside the square structure 41. The four rectangular structures 43 are evenly distributed outside the square structure 41, with each rectangular structure 43 intersecting perpendicularly with the side of the square structure 41. One end of the rectangular structure 43 contacts the side of the square structure 41, and the other end is embedded in the cylindrical structure 42, extending to the edge of the metamaterial unit. The square structure 41, the cylindrical structure 42, and the four rectangular structures 43 are integrally formed.

[0032] Furthermore, the square structure 41 has a side length L=7μm and a thickness of 3.4μm, a hollow cylinder diameter D=2μm and a height of 3.4μm; the cylindrical structure 42 has an inner diameter r=8μm, an outer diameter R=9μm and a thickness of 3.4μm; and the rectangular structure 43 has a width of 1μm and a thickness of 3.4μm.

[0033] Graphene layer 3 is a single layer of graphene with a thickness of 0.34 nm and a length and width of 20 μm.

[0034] The dielectric layer 2 has a thickness of 4.6 μm, a length and width of 20 μm, is made of titanium dioxide, and has a refractive index of 2.84.

[0035] The metallic reflective layer is a gold film with a thickness of 0.2 μm and a length and width of 20 μm.

[0036] Next, the working principle of this embodiment will be described in detail so that those skilled in the art can better understand this utility model:

[0037] This invention relates to a far-infrared metamaterial absorber composed of a Dirac half-metal layer, a graphene layer, a dielectric layer, and a metal reflective layer. Through optimization of the design of each layer and the patterned structure of the Dirac half-metal layer, multiple resonators are formed, creating complex resonance modes, including localized surface plasmon resonance (LSPR), cavity resonance (CR), and gap resonance, as well as their combined effects. When far-infrared waves are incident on this structure, the following resonances may occur: Surface plasmon resonance is excited at the interface between the Dirac half-metal layer and titanium dioxide, generating a strong electric field and achieving strong absorption of electromagnetic waves; in the far-infrared band... Firstly, graphene has a conductivity greater than zero, exhibiting metallic properties, thus creating cavity resonance between graphene and the opaque gold layer. After the incident wave enters the dielectric layer, it interferes destructively with its reflected wave, forcing the incident light to undergo multiple reflections within the cavity until it is completely dissipated by the medium, thereby achieving strong absorption of electromagnetic waves. Through the complex coupling of these resonance mechanisms and impedance matching, perfect absorption in eight narrowbands in the 8-15Thz frequency band is achieved. Secondly, graphene and Dirac half-metals can change their optical properties through Fermi level changes, and their Fermi levels can be changed by an applied bias voltage, thereby achieving dynamic tuning of multiple narrowbands and wide-narrowband switching.

[0038] Figure 4 The graph shows a comparison of the absorption spectra of the far-infrared metamaterial absorber in this embodiment when the Fermi level of graphene is 0.4 eV and the Fermi levels of the Dirac semimetal are 0.5 eV and 0.07 eV, respectively. As can be seen from the graph, when the Fermi level of the Dirac semimetal is 0.5 eV and the Fermi level of graphene is 0.4 eV, this structure can achieve perfect absorption at frequencies of 8.30813, 10.2059, 10.7012, 11.8773, 12.5246, 12.8518, 14.0471, and 14.4991 THz. The resonant peaks of these eight narrowbands are respectively set as M... The absorption rates of 1 to M8 are 97.86%, 99.91%, 98.88%, 99.93%, 94.55%, 100%, 99.67%, and 99.83%, respectively, all above 94%, indicating that the structure has a multi-narrowband absorption effect. Keeping the Fermi level of graphene constant at 0.4 eV, when the Fermi level of the Dirac half-metal reaches 0.07 eV, the structure achieves 91.21% absorption in the 11.2532-14.7864 THz frequency band, exhibiting a broadband absorption effect, indicating that the far-infrared metamaterial absorber of the present invention has a wide-narrowband switching function.

[0039] Figure 5 The absorption spectrum of the far-infrared metamaterial absorber in this embodiment as a function of the Dirac half-metal Fermi level when the Fermi level of graphene is 0.4 eV. Figure 6The absorption spectrum of the far-infrared metamaterial absorber in this embodiment varies with the graphene Fermi level, where the Dirac half-metal Fermi level is 0.5 eV.

[0040] Figure 7 The graph shows the peak frequency of the far-infrared metamaterial absorber in this embodiment as a function of the BDS Fermi level. Keeping the Fermi level of graphene constant at 0.4 eV, the Fermi level of BDS varies from 0.4 to 0.9 eV, resulting in maximum tunable amplitudes of M1, M2...M8 of 0.0592, 0.0504, 0.0656, 0.0648, 0.0585, 0.092, 0.1536, and 0.0985 THz, respectively. Figure 8 The graph shows the peak frequency of the far-infrared metamaterial absorber in this embodiment as a function of the graphene Fermi level. Keeping the Fermi level of BDS constant at 0.5 eV, the Fermi level of graphene varies from 0.1 to 0.9 eV, resulting in maximum tunable amplitudes of M1, M2...M8 of 0.2, 0.0272, 0.0504, 0.0896, 0.0905, 0.164, 0.2816, and 0.2729 THz, respectively.

[0041] from Figure 5 and Figure 7 It can be seen that as the Fermi level of the Dirac half-metal increases, the resonance peak shifts to higher frequencies, and all modes of the absorber exhibit a certain degree of blue shift. From Figure 6 and Figure 8 As can be seen, with the increase of the Fermi level of graphene, most of the resonance peaks first shift to higher frequencies and then to lower frequencies, and each mode of the absorber is redshifted to a certain extent. The above results show that the far-infrared metamaterial absorber of the present invention has a dynamic tuning function.

[0042] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the present invention to the precise forms disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although embodiments of the present invention have been shown and described, these specific embodiments are merely explanations of the present invention and are not intended to limit the invention. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. The purpose of selecting and describing exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art, after reading this specification, can make modifications, substitutions, variations, and various choices and changes to the embodiments as needed without departing from the principles and spirit of the present invention, provided that such modifications, substitutions, variations, and choices and changes are within the scope of the claims of the present invention and are protected by patent law.

Claims

1. A multifunctional far-infrared metamaterial absorber, characterized in that, It includes metamaterial units arranged in a periodic array; The metamaterial unit is a stacked structure, which includes, from top to bottom: a Dirac semimetal layer (4), a graphene layer (3), a dielectric layer (2), and a metal reflective layer (1); the Dirac semimetal layer (4) is rudder-shaped and includes a square structure (41) with a hollow cylinder in the center, a cylindrical structure (42), and four rectangular structures (43). The cylindrical structure (42) is located outside the square structure (41). The square structure (41) and the cylindrical structure (42) are arranged concentrically. The four rectangular structures (43) are evenly distributed outside the square structure (41). The four rectangular structures (43) intersect the side of the square structure (41) perpendicularly, with one end in contact with the side of the square structure (41) and the other end embedded in the cylindrical structure (42), extending to the edge of the metamaterial unit.

2. The far-infrared metamaterial absorber according to claim 1, characterized in that, The metamaterial unit has a periodic size of 20μm*20μm; the square structure (41) has a side length of 7μm, a thickness of 3.4μm, a hollow cylinder diameter of 2μm, and a height of 3.4μm; the cylindrical structure (42) has an inner radius of 8μm, an outer radius of 9μm, and a thickness of 3.4μm; the rectangular structure (43) has a width of 1μm and a thickness of 3.4μm.

3. The far-infrared metamaterial absorber according to claim 1, characterized in that, The graphene layer (3) is a single layer of graphene with a thickness of 0.34 nm and a length and width of 20 μm.

4. The far-infrared metamaterial absorber according to claim 1, characterized in that, The dielectric layer (2) has a thickness of 4.6 μm and a length and width of 20 μm.

5. The far-infrared metamaterial absorber according to claim 1, characterized in that, The dielectric layer (2) is made of titanium dioxide.

6. The far-infrared metamaterial absorber according to claim 1, characterized in that, The metal reflective layer (1) has a thickness of 0.2 μm and a length and width of 20 μm.

7. The far-infrared metamaterial absorber according to claim 1, characterized in that, The metal reflective layer (1) is made of gold.

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