Ultra-wideband electromagnetic wave absorption device and design method and application thereof

Abstract

The invention relates to an ultra-wideband electromagnetic wave absorption device and a design method and application thereof. The design method of the electromagnetic wave absorbing device comprises the following steps: establishing an electromagnetic wave absorbing device model which comprises a metal reflecting layer, a first absorbing layer, a transparent isolating layer and a second absorbing layer with a metasurface structure which are arranged in sequence; randomly generating a population formed by a plurality of metasurface structure shapes; evaluating the wave absorbing performance of the electromagnetic wave absorbing device model corresponding to the population, and sorting the plurality of shapes in the population based on an evaluation result; selecting a first plurality of shapes having optimal wave absorbing properties based on the ranking; performing crossover and mutation operation on at least one part of shapes in the population to obtain a plurality of second shapes; and iteratively performing evaluation, sorting, selection, and crossover and mutation operations based on the updated population including the first and second plurality of shapes until the wave absorbing performance of the electromagnetic wave absorbing device model corresponding to the one or more metasurface structure shapes reaches a predetermined level.

Description

Technical Field

[0001] The present invention generally relates to the field of wave absorbing devices, and in particular, to a high-efficiency ultra-wideband electromagnetic wave absorbing device and a design method and application thereof. Background Art

[0002] Absorbing materials refer to materials that can absorb or significantly reduce the electromagnetic wave energy received on their surface, thereby reducing electromagnetic interference or electromagnetic wave reflection. Such materials have broad and important application value in electromagnetic stealth, solar photovoltaics, communications, light detection, photocatalysis and light modulation. Ideal absorbing materials can achieve near-perfect absorption over a wide band, so they are also called "blackbody absorbers." However, in reality, ideal absorbing materials with such properties have not yet been found. Generally, absorbing materials can only achieve high electromagnetic wave absorption within a specific band. In order to broaden the frequency range of absorbing waves, one solution is to use a variety of absorbing materials to form a laminated structure, but it is still difficult to achieve good electromagnetic wave absorption over a wide band.

[0003] In recent years, metasurfaces, as an artificial micro-nanostructure with sub-wavelength thickness, have attracted much attention due to their powerful light field control capabilities. It has been proposed to apply metasurface structures to absorbers to control the amplitude, phase, and polarization state of incident electromagnetic waves, thereby achieving high absorption rates over a wide band, which is considered to be an ideal candidate for building a new type of perfect electromagnetic wave absorber. Despite this, current metasurface absorbers still face technical bottlenecks that make it difficult to simultaneously take into account light absorption efficiency and absorption bandwidth, or have a narrow absorption bandwidth or a low absorption rate, which significantly limits their promotion in practical applications.

[0004] Therefore, it is still necessary to study new absorbers with both high light absorption efficiency and wide absorption band, which is the core problem that needs to be solved in this field. However, the traditional device design method relies on repeated trial and error, which is inefficient, consumes a lot of manpower and material resources, and is still progressing slowly. Summary of the invention

[0005] The development of computer technology, especially artificial intelligence (AI), has brought new models for material screening and device design, which can greatly improve the research and development efficiency of new materials and new devices. The present invention proposes a method for designing an electromagnetic wave absorption device based on a genetic algorithm, and successfully designs an electromagnetic wave absorption device with ultra-wide band high absorption rate. The present invention also provides an electromagnetic wave absorption device with ultra-wide band high absorption rate and a device using the electromagnetic wave absorption device.

[0006] According to one embodiment, a design method for an electromagnetic wave absorption device may include: establishing an electromagnetic wave absorption device model, the electromagnetic wave absorption device model including a metal reflection layer, a first absorption layer, a transparent isolation layer and a second absorption layer arranged in sequence, the second absorption layer having a metasurface structure; randomly generating a plurality of metasurface structure shapes, the plurality of metasurface structure shapes forming a population; evaluating the wave absorption performance of the electromagnetic wave absorption device model corresponding to the plurality of metasurface structure shapes, and sorting the plurality of metasurface structure shapes in the population based on the evaluation result; based on the sorting, selecting a first plurality of metasurface structure shapes with the best wave absorption performance from the population; performing crossover and mutation operations on at least a portion of the metasurface structure shapes in the population to obtain a second plurality of metasurface structure shapes; and iteratively performing the evaluation, sorting, selection, and crossover and mutation operations based on an updated population including the first plurality of metasurface structure shapes and the second plurality of metasurface structure shapes until the wave absorption performance of the electromagnetic wave absorption device model corresponding to one or more metasurface structure shapes reaches a predetermined level.

[0007] According to an embodiment, randomly generating a plurality of metasurface structure shapes may include: randomly generating a portion of a metasurface structure shape; and determining a complete metasurface structure shape based on symmetry.

[0008] According to an embodiment, randomly generating a plurality of hypersurface structure shapes may further include: using a Bessel function to smooth the hypersurface structure shapes.

[0009] According to one embodiment, an electromagnetic wave absorption device may include: a substrate; a metal reflective layer arranged on the substrate; a first absorption layer arranged on the metal reflective layer; a transparent isolation layer arranged on the first absorption layer; and a second absorption layer arranged on the transparent isolation layer, wherein the first absorption layer, the transparent isolation layer and the second absorption layer form a Fabry-Perot resonant cavity, and the second absorption layer has a metasurface structure, and the metasurface structure has a nanoflower unit shape.

[0010] According to one embodiment, the metal reflective layer includes one or more of chromium, silver and aluminum, the first absorption layer includes one or more of germanium antimony telluride alloy, silicon nitride, and titanium dioxide, the transparent isolation layer includes silicon dioxide, and the second absorption layer includes germanium antimony telluride alloy, and the germanium antimony telluride alloy is selected from Ge2Sb2Te5, Ge3Sb2Te6, GeSb4Te7 and GeSb2Te4.

[0011] According to one embodiment, the nanoflower unit shape has C4 symmetry and has a maximum in-plane size of 50 nm to 1000 nm.

[0012] According to one embodiment, the thickness of the nanoflower unit shape is in the range of 50nm to 400nm, preferably in the range of 50nm to 200nm. In the super surface structure, the period of the nanoflower unit shape is in the range of 100nm to 2000nm, preferably in the range of 200nm to 1500nm.

[0013] According to one embodiment, the thickness of the metal reflective layer is in the range of 50nm to 500nm, preferably in the range of 100nm to 300nm, the thickness of the first absorption layer is in the range of 20nm to 500nm, preferably in the range of 50nm to 350nm, and the thickness of the transparent isolation layer is in the range of 10nm to 200nm, preferably in the range of 20nm to 100nm.

[0014] According to an embodiment, the first absorption layer and the transparent isolation layer are alternately stacked in a plurality of periods, and the transparent isolation layers in at least two periods have different thicknesses.

[0015] According to one embodiment, a device is provided, on the surface of which the above-mentioned electromagnetic wave absorbing device is arranged.

[0016] The above and other features and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of a method for designing an electromagnetic wave absorption device according to an embodiment of the present invention.

[0018] Figure 2 is a schematic diagram of an electromagnetic wave absorption device model according to an embodiment of the present invention.

[0019] Figure 3A , 3B and 3C is based on Figure 1 Schematic diagram of multiple metasurface structure shapes determined by the method.

[0020] Figure 4 Schematic diagram of the structure of an electromagnetic wave absorption device according to an embodiment of the present invention.

[0021] Figure 5 is a microscopic photograph of a super-surface structure according to an embodiment of the present invention.

[0022] Figure 6 1 is an absorption and reflection spectrum of an electromagnetic wave absorption device according to an embodiment of the present invention.

[0023] Figure 7 Schematic diagram of a device having an electromagnetic wave absorbing device disposed on the surface according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the accompanying drawings may not be drawn to scale.

[0025] Figure 1 The flowchart of the design method of the electromagnetic wave absorption device according to one embodiment of the present invention is shown in FIG. 1. In the method, a genetic algorithm is used to optimize and screen the design of the electromagnetic wave absorption device by using computer tools, thereby greatly improving the design efficiency.

[0026] Reference Figure 1 In step 110, a model of the electromagnetic wave absorption device may be established. The model of the electromagnetic wave absorption device may be established using simulation software. Figure 2 An example of an electromagnetic wave absorption device model is shown in Figure 2 As shown, the model may include a metal reflective layer 210, a first absorption layer 220, a transparent isolation layer 230 and a second absorption layer 240 arranged in sequence. Figure 2 In the model example shown, the upper surface of the second absorption layer 240 (electromagnetic wave incident surface) can be formed with a metasurface structure. The term "metasurface" refers to an artificial layered structure with a thickness less than the wavelength, usually composed of periodic or quasi-periodic sub-wavelength unit structures, which can realize the regulation of basic properties of electromagnetic waves such as polarization, amplitude and phase. By changing the geometric parameters of the structural units, the metasurface can achieve highly precise electromagnetic wave manipulation, such as electromagnetic wave absorption. In this model, the material, thickness and other properties of each layer can also be set, which will not be described in detail here.

[0027] In step 120, multiple hypersurface structure shapes, that is, the shapes of the unit structures in the hypersurface structure, can be randomly generated, and these multiple hypersurface structure shapes are used as the initial population. For example, in one embodiment, multiple point coordinates can be randomly generated to define a hypersurface structure shape, and the coordinates can be expressed in a plane coordinate system or a polar coordinate system. In another embodiment, a part of the hypersurface structure shape can be randomly generated first, and then based on symmetry, the complete hypersurface structure shape is determined from the generated part of the shape. For example, a group (e.g., 8, or more or less) of random numbers can be generated, as different radius distances from the center point, and the radius values ​​represented by the group of random numbers are separated at the same angle within a range of 90 degrees to obtain a shape curve within a range of 90 degrees, and then based on C4 rotational symmetry, a complete hypersurface structure shape within a range of 360 degrees is obtained. It should be understood that these are only examples, and multiple hypersurface structure shapes can also be randomly generated in any other way to form an initial population. In some embodiments, the generated hypersurface structure shape can also be smoothed using a Bessel function. For example, a piecewise smoothing method can be used, and multiple points in a shape curve are selected each time as control points and input into the Bessel function to obtain a smooth curve; each smoothed shape curve is connected end to end, that is, the last control point of the previous shape curve is the first control point of the next shape curve, and finally the smoothing of the entire super surface structure shape is achieved. It should be understood that a part of the shape of the super surface structure can be generated first, the part is smoothed, and then based on the symmetry, the smoothed part of the shape curve is used to determine the complete shape of the super surface structure; or after determining the complete shape of the super surface structure, the Bessel function can be used to smooth the complete shape of the super surface structure. In one embodiment, in addition to generating the contour shape parameters of the unit structure of the super surface structure in step 120, other parameters of the unit structure can also be generated, such as thickness parameters and period parameters, etc., which together define the super surface structure.

[0028] Then, in step 130, the generated multiple metasurface structure shapes can be applied to the electromagnetic wave absorption device model established in step 110, or more precisely, to the metasurface structure of the second absorption layer 240 in the model, and the electromagnetic wave absorption performance of the model can be evaluated. As an example, the FDTD optical simulation software produced by Lumerical Solutions of Canada can be used to simulate the absorption spectrum of the electromagnetic wave absorption device model with the corresponding metasurface structure shape in a predetermined band (for example, an ultra-wide band including infrared, visible light and ultraviolet bands), so as to evaluate its electromagnetic wave absorption performance. Of course, other optical simulation software can also be used. In some embodiments, the wave absorption performance of the electromagnetic wave absorption device model can be evaluated based on the following function:

[0029]

[0031] Where F is also called the fitness function, θ is the incident angle of the electromagnetic wave, λ is the wavelength of the electromagnetic wave, is the absorptivity of the transverse electric wave (also called s-wave), is the absorption rate of transverse magnetic waves (also called p-waves). In step 130, the wave absorption performance of each metasurface structure shape in the initial population can also be sorted based on the evaluation result, that is, the value of the F function, for example, from high to low.

[0032] In step 140, it can be determined whether there are one or more (e.g., a predetermined number) metasurface structure shapes whose absorption performance reaches a predetermined level, such as the value of the above-mentioned F function has reached or exceeded a predetermined value. If such a metasurface structure shape exists, it can be considered that a metasurface structure shape with good electromagnetic wave absorption performance has been obtained, and the method can end in step 142. If such a metasurface structure shape does not exist, the subsequent steps of the method can be continued.

[0033] In step 150, multiple metasurface structural shapes with the best wave absorbing performance can be selected from the multiple metasurface structural shapes of the initial population based on the sorting results of step 130 as good genes for inheritance to the next generation, i.e., the updated population described below. In some embodiments, a predetermined number or a predetermined proportion of the best metasurface structural shapes can be selected.

[0034] In step 160, at least a portion of the super surface structure shapes in the initial population (for example, those with better wave absorption performance) can be crossover and mutation operations to obtain multiple new super surface structure shapes. Here, the crossover process refers to exchanging one or more points (for example, radius values) in two super surface structure shapes to form two new super surface structure shapes, which is similar to the gene exchange of chromosomes; the mutation operation refers to changing the value of one or more points in the super surface structure shape, which is similar to the gene mutation of chromosomes. It can be understood that the degree of change can be controlled in the crossover and mutation process, for example, the difference between the two values ​​exchanged with each other during the crossover process should be within a preset threshold range, or a value can only change within a predetermined range (for example, within the range of ±10%) during the mutation process. In some embodiments, in step 160, other parameters of the super surface structure shape, such as thickness, period, etc., are also crossover and mutation operations are performed, so that these parameters can also be optimized and screened.

[0035] Then, the multiple metasurface structure shapes with the best absorption performance determined in step 150 and the multiple new metasurface structure shapes determined in step 160 can be used together to form an updated population, and the above-mentioned evaluation and sorting step 130, judgment step 140, selection step 150, and crossover and mutation step 160 are iteratively performed using the updated population until the absorption performance of the electromagnetic wave absorption device model corresponding to one or more (for example, a predetermined number) metasurface structure shapes reaches a predetermined level, so that the process ends in step 142.

[0036] exist Figure 1 In the method shown, since the updated population includes both the metasurface structure shapes (excellent genes) with excellent wave absorption performance in the original population and the new metasurface structure shapes (new genes) generated by crossover and mutation, the excellent genes can be inherited, and further gene improvement can be obtained through the new genes. Therefore, by iteratively executing the above steps, the metasurface structure shapes can be continuously optimized and screened, and finally the metasurface structure shapes with the desired wave absorption performance can be obtained. The method can be automatically executed by a computer program, thus greatly improving the research and development efficiency of electromagnetic wave absorption devices and saving manpower and material resources.

[0037] Figure 3A , 3B and 3C is based on Figure 1 Schematic diagram of multiple metasurface structures with excellent ultra-wideband absorbing performance determined by the method. Figure 3A , 3B As shown in Figure 3C, the obtained metasurface structure is in the shape of a nanoflower, which has a central part and four petal parts extending outward from the central part, and the four petal parts have the same shape, that is, they have C4 rotational symmetry. Each petal is connected to the central part to form an integral structure, that is, each nanoflower has a continuous and closed outer contour. Although it is called a nanoflower, its maximum in-plane size can be hundreds or even thousands of nanometers, that is, reaching the micrometer level, which will be described in further detail below. The simulation results show that for Figure 3A The shape shown has an absorption rate of 93.17% for vertically incident electromagnetic waves (incident angle of 0 degrees), 93.92% for TE waves incident at an angle of 45 degrees, and 87.96% for TM waves incident at an angle of 45 degrees; Figure 3B The shape shown has an absorption rate of 93.58% for vertically incident electromagnetic waves (incident angle of 0 degrees), an absorption rate of TE waves incident at an angle of 45 degrees, and an absorption rate of 88.32% for TM waves incident at an angle of 45 degrees; Figure 3CThe shape shown has an absorption rate of 93.51% for vertically incident electromagnetic waves (incident angle of 0 degrees), 95.00% for TE waves incident at an angle of 45 degrees, and 88.25% for TM waves incident at an angle of 45 degrees. It should be understood that Figure 3A , 3B The shapes shown in 3C are only examples, and the shape of the nanoflower may not be limited to the specific shape shown in the figure. For example, depending on the material and model structure, other nanoflower shapes with high absorption rate in ultra-wide band may be obtained.

[0038] Figure 4 is a schematic diagram of the structure of an electromagnetic wave absorption device according to an embodiment of the present invention, which includes a nanoflower-shaped super surface structure designed and determined by the above method. Figure 4 The electromagnetic wave absorption device includes a metal reflection layer 310, a first absorption layer 320, a transparent isolation layer 330 and a second absorption layer 340 which are sequentially arranged on a substrate 301.

[0039] The substrate 301 may be made of a suitable material as required. For example, the substrate 301 may be a surface material of a device to which an electromagnetic wave absorbing device is to be applied, and examples thereof include but are not limited to silicon, metal, polymer material (such as PDMS, etc.), sapphire, glass, quartz, etc. The substrate 301 may be a rigid substrate or a flexible substrate, and may have an appropriate thickness to provide support for multiple layers thereon. In one embodiment, a buffer layer may also be formed on the substrate 301, so as to form a desired absorbing functional layer on the buffer layer.

[0040] The metal reflective layer 310 may include a metal with good reflectivity, such as one or more of chromium, silver, and aluminum. Moreover, metal materials generally have good infrared absorption characteristics, so the metal reflective layer 310 is also used as an infrared band absorption layer. The thickness of the metal reflective layer 310 may generally be in the range of 50nm to 500nm, and is preferably in the range of 100nm to 300nm in consideration of good reflection and infrared absorption effects and cost efficiency.

[0041] The first absorption layer 320, the transparent isolation layer 330 and the second absorption layer 340 can form a Fabry-Perot resonant cavity structure, so that the electromagnetic wave can resonate back and forth between the first absorption layer 320 and the second absorption layer 340, thereby being repeatedly absorbed to improve the absorption efficiency. The first absorption layer 320 may include, for example, but not limited to, absorbing materials such as germanium antimony telluride alloy, silicon nitride, titanium dioxide, and the like, and the thickness may be in the range of 20nm to 500nm, preferably in the range of 50nm to 350nm. The transparent isolation layer 330 may include, for example, commonly used silicon dioxide, and its thickness may be in the range of 10nm to 200nm, preferably in the range of 20nm to 100nm. The second absorption layer 340 may include, for example, germanium antimony telluride alloy, and its upper surface (i.e., the electromagnetic wave incident surface) may be formed with a supersurface structure, including periodically or quasi-periodically arranged sub-wavelength unit structures, and these unit structures may have the above according to Figure 1 The method shown determines the shape of the nanoflower. Figure 4 The unit structure of the nanoflower shape only extends a portion of the entire thickness of the second absorption layer 340, but in other embodiments, the nanoflower shape can also extend the entire thickness of the second absorption layer 340. The germanium antimony telluride alloy that can be used to form the first absorption layer 320 and the second absorption layer 340 may include, for example, Ge2Sb2Te5, Ge3Sb2Te6, GeSb4Te7 and GeSb2Te4, and the first absorption layer 320 and the second absorption layer 340 can be formed of the same or different germanium antimony telluride alloys.

[0042] In some embodiments, the thickness of the nanoflower structure may be in the range of 50nm to 400nm. When the thickness of the nanoflower structure is less than 50nm, it may cause low electromagnetic wave absorption efficiency; and when the thickness of the nanoflower structure is greater than 400nm, it may cause difficulty in dissolution during sample manufacturing. Considering the electromagnetic wave absorption efficiency and manufacturing difficulty, in the following embodiments, it is preferred that the thickness of the nanoflower structure may be in the range of 50nm to 200nm.

[0043] The parameters such as the in-plane size and period of the nanoflower structure can be set according to the design of the super surface structure. In some embodiments, the maximum in-plane size of the nanoflower structure can be in the range of 50nm to 1000nm, and the arrangement period can be in the range of 100nm to 2000nm. When the period is less than 100nm, it may be difficult to process because the line width is too narrow; when the period is greater than 2000nm, the characteristic size of the structural unit is greater than the wavelength of the electromagnetic wave, which exceeds the ability of the super surface structure to regulate the light field, and may cause a decrease in absorption rate. In some embodiments, preferably, the arrangement period of the nanoflower structure can be in the range of 200nm to 1500nm. In addition to arrays in rows and columns, the nanoflower structure can be arranged in other patterns, such as but not limited to concentric circle patterns, spiral patterns, and the like. In different directions in the plane, such as along the X-axis and Y-axis directions perpendicular to each other, the nanoflower structure can have the same or different arrangement periods.

[0044] In some embodiments, the first absorption layer 320 and the transparent isolation layer 330 can be alternately stacked in multiple periods, and the first absorption layer 320 and the topmost second absorption layer 340 in each period together (including the transparent isolation layer therebetween) form a Fabry-Perot resonant cavity. These Fabry-Perot resonant cavities can have different resonance distances, i.e., the distance between the first absorption layer 320 and the second absorption layer 340, thereby helping to improve the absorption efficiency within an ultra-wide band range.

[0045] The metal reflective layer 310, the first absorption layer 320, the transparent isolation layer 330 and the second absorption layer 340 can be formed by various film-forming processes, examples of which include but are not limited to physical vapor deposition methods such as electron beam evaporation deposition and magnetron sputtering deposition, chemical vapor deposition methods such as plasma enhanced chemical vapor deposition and atomic layer deposition, or thin film coating methods such as spin coating and spraying. The nanoflower shape in the super surface structure of the second absorption layer 340 can be formed by photolithography and pattern transfer methods. The photolithography method may include direct writing exposure methods such as electron beam lithography and laser direct writing, and also includes template exposure methods such as deep ultraviolet lithography and subsequent development and fixing processes. The pattern transfer can be electron beam deposition, magnetron sputtering deposition and subsequent pattern stripping methods, or etching methods such as reactive ion etching and ion beam etching. It should be understood that these processes themselves are commonly used in the prior art and will not be repeated here.

[0046] An example of the electromagnetic wave absorption device of the present invention is described below, and its structure from bottom to top is a silicon wafer substrate, a 200-nanometer-thick chromium layer, a 50-nanometer-thick germanium antimony telluride layer, a 50-nanometer-thick silicon dioxide layer, and a 100-nanometer-thick germanium antimony telluride supersurface structure layer. The specific preparation method is: using electron beam evaporation technology, wherein the electron gun acceleration power is about 10 kilowatts and the deposition rate is about 3nm per minute, a chromium film is deposited on the substrate surface. Then, using magnetron sputtering deposition technology, a germanium antimony telluride film is deposited on the chromium film, wherein the deposition power is about 100 watts and the deposition rate is about 6nm per minute. Then, using plasma enhanced chemical vapor deposition technology, the deposition power is about 350 watts and the deposition rate is about 25.8nm per minute, a silicon dioxide film is grown on the germanium antimony telluride film. Afterwards, a photoresist layer is spin-coated on the silicon dioxide film using a coating machine, and the corresponding nanoflower pattern is exposed by electron beam exposure technology, wherein the electron gun acceleration voltage during electron beam exposure is about 100 kilovolts. Finally, the germanium antimony telluride alloy is deposited by magnetron sputtering deposition technology, and the residual photoresist layer and the germanium antimony telluride alloy material thereon are melted off, leaving the germanium antimony telluride alloy material in the nanoflower pattern, wherein the deposition power during magnetron sputtering deposition of germanium antimony telluride is about 100 watts, and the deposition rate is about 6nm per minute, thereby obtaining a super surface structure of the desired shape.

[0047] Figure 5 FIG3 is a scanning electron microscope morphology image of the Germanium Antimony Telluride alloy supersurface structure in the above example, showing the nanoflower-shaped structure therein. As can be seen from FIG3 , uniform and regularly arranged nanoflower shapes are formed in the supersurface structure, wherein the period of the nanoflower structure is about 1300 nm.

[0048] Figure 6 The above is the absorption and reflection spectrum test curve of the electromagnetic wave absorption device example in the ultra-wide band, where the upper curve is the absorption spectrum and the lower curve is the reflection spectrum. Figure 6 As shown in the figure, the ultra-wide band covers visible light (380nm to 780nm range, as shown by the dotted line in the figure), infrared (the right side of the visible light range, 780nm to 2500nm) and ultraviolet (the left side of the visible light range, 250nm to 380nm) bands. In the entire measured band range (250nm to 2500nm), the minimum value of the absorptivity is above 80%, and the average value reaches about 90%, especially in the visible light range. It has a very high absorptivity. This proves that the ultra-wideband absorber of the metasurface of the present invention can achieve near-perfect absorption of electromagnetic waves from ultraviolet to infrared bands.

[0049] Figure 7 A schematic diagram showing a device in which the electromagnetic wave absorption device of the present invention is applied. Figure 7As shown, the electromagnetic wave absorption device 420 of the present invention can be arranged on the device surface 410, and the device surface 410 can be any surface of the device that needs to absorb electromagnetic waves, such as the outer surface, or the surface of a component inside the device. It should be understood that the electromagnetic wave absorption device 420 can use the device surface 410 as a substrate, or can include a separate substrate. When electromagnetic waves are irradiated onto the electromagnetic wave absorption device 420, it can achieve good electromagnetic wave absorption over an ultra-wide band range.

[0050] The present invention has the following beneficial effects:

[0051] Traditional electromagnetic wave absorbers are made of conventional metal materials and dielectric materials, and it is difficult to achieve high absorption rate and wide absorption band at the same time. The present invention uses germanium antimony tellurium alloy material to form a Fabry-Perot resonant cavity and a metasurface structure with four-fold rotational symmetry, so that the absorber of the present invention has a wide absorption band, covering an ultra-wide absorption band from the ultraviolet band to the infrared band, and has a high absorption rate. While maintaining a wide band, it can also maintain an extremely high absorption rate, with an average absorption rate of more than 90%.

[0052] The absorber of the present invention does not depend on the polarization state of the incident electromagnetic wave, and can achieve perfect absorption for TE waves, TM waves and non-polarized light. The absorber of the present invention can also maintain a high absorption rate for electromagnetic waves incident at large angles. The absorber of the present invention has extremely high application value in solar photovoltaic, electromagnetic stealth, light detection, photocatalysis and light modulators.

[0053] In addition, the absorber of the present invention has a simple preparation process, short time consumption, low material cost, and can be prepared on a large area.

[0054] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise", "comprising", "including", "comprising", etc. should be interpreted in an inclusive sense, rather than an exclusive or exhaustive sense. That is, the meaning is "including but not limited to". The word "connected" as generally used herein refers to two or more elements that can be directly connected or connected through one or more intermediate elements. As generally used herein, the word "connected" refers to two or more elements that can be directly connected or connected through one or more intermediate elements. In addition, when used in this application, the words "herein", "above", "below" and words of similar meanings should refer to the entirety of this application rather than to any particular part of this application. Where the context permits, the word "or" refers to a list of two or more items, which covers all of the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list.

[0055] Furthermore, unless otherwise specifically stated or understood in the context of use, conditional language used herein, such as "can," "may," "might," "could," "for example," "for example," "such as," and the like, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or states. Thus, such conditional language is generally not intended to imply that one or more embodiments require features, elements, and / or states in any way, or that one or more embodiments must include logic for making decisions, with or without author input or prompting, that such features, elements, and / or states are included or will be performed in any particular embodiment.

[0056] Although certain embodiments have been described, these embodiments are presented only by way of example and are not intended to limit the scope of the present disclosure. In fact, the novel facilities, methods, and systems described herein may be embodied in various other forms; in addition, various omissions, substitutions, and changes may be made to the forms of the methods and systems described herein without departing from the spirit of the present disclosure. For example, although blocks are presented in a given arrangement, alternative embodiments may perform functions similar to different components and / or circuit topologies, and may delete, move, add, subdivide, combine, and / or modify some blocks. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and actions of the various embodiments described above may be combined to provide further embodiments. The attached claims and their equivalents are intended to cover these forms or modifications that fall within the scope and spirit of the present disclosure.

[0057] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for designing an electromagnetic wave absorbing device, comprising: Establishing an electromagnetic wave absorption device model, wherein the electromagnetic wave absorption device model comprises a metal reflection layer, a first absorption layer, a transparent isolation layer and a second absorption layer arranged in sequence, wherein the second absorption layer has a metasurface structure; Randomly generate a plurality of hypersurface structure shapes, wherein the plurality of hypersurface structure shapes form a population; Evaluating the wave absorbing performance of the electromagnetic wave absorbing device model corresponding to the multiple metasurface structure shapes, and sorting the multiple metasurface structure shapes in the population based on the evaluation result; Based on the ranking, selecting a first plurality of metasurface structure shapes having the best wave absorbing performance from the population; Performing crossover and mutation operations on at least a portion of the hypersurface structure shapes in the population to obtain a second plurality of hypersurface structure shapes; Based on the updated population including the first plurality of metasurface structure shapes and the second plurality of metasurface structure shapes, the evaluation, sorting, selection, crossover and mutation operations are iteratively performed until the absorption performance of the electromagnetic wave absorption device model corresponding to one or more metasurface structure shapes reaches a predetermined level.

2. The method of claim 1, wherein: Randomly generate multiple metasurface structure shapes including: randomly generating a portion of the shape of the metasurface structure; and The complete metasurface structure shape is determined based on symmetry.

3. The method of claim 2, wherein: Randomly generate multiple metasurface structure shapes also include: The Bessel function is used to smooth the shape of the metasurface structure.

4. An electromagnetic wave absorbing device, comprising: substrate; A metal reflective layer disposed on the substrate; A first absorption layer disposed on the metal reflective layer; a transparent isolation layer disposed on the first absorbing layer; as well as A second absorbing layer disposed on the transparent isolation layer, wherein the first absorption layer, the transparent isolation layer and the second absorption layer form a Fabry-Perot resonant cavity, and The second absorption layer has a super surface structure, and the super surface structure has a nano flower unit shape.

5. The electromagnetic wave absorption device according to claim 4, wherein: The metal reflective layer includes one or more of chromium, silver and aluminum, The first absorption layer includes one or more of germanium antimony telluride alloy, silicon nitride, and titanium dioxide. The transparent isolation layer comprises silicon dioxide, The second absorption layer includes germanium antimony tellurium alloy, The germanium antimony tellurium alloy is selected from Ge2Sb2Te5, Ge3Sb2Te6, GeSb4Te7 and GeSb2Te4.

6. The electromagnetic wave absorption device according to claim 4, wherein: The nanoflower unit shape has C4 symmetry and has a maximum in-plane dimension of 50nm to 1000nm.

7. The electromagnetic wave absorption device according to claim 6, wherein: The thickness of the nanoflower unit shape is in the range of 50nm to 400nm, preferably in the range of 50nm to 200nm, and In the supersurface structure, the period of the nanoflower unit shape is in the range of 100nm to 2000nm, preferably in the range of 200nm to 1500nm.

8. The electromagnetic wave absorption device according to claim 4, wherein: The thickness of the metal reflective layer is in the range of 50 nm to 500 nm, preferably in the range of 100 nm to 300 nm. The thickness of the first absorption layer is in the range of 20 nm to 500 nm, preferably in the range of 50 nm to 350 nm. The thickness of the transparent isolation layer is in the range of 10 nm to 200 nm, preferably in the range of 20 nm to 100 nm.

9. The electromagnetic wave absorption device according to claim 4, wherein: The first absorption layer and the transparent isolation layer are alternately stacked in a plurality of periods, and the transparent isolation layers in at least two periods have different thicknesses.

10. A device, the surface of which is provided with the electromagnetic wave absorbing device according to any one of claims 4 to 9.

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