A multi-band terahertz energy harvester of nested octagonal structure

Abstract

The application discloses a kind of nested octagon structure multi-band terahertz energy collector, belong to terahertz regulation technical field, including several periodic arrangement resonant cavity;Each resonant cavity includes from bottom to top sequentially arranged reflection bottom plate, intermediate dielectric layer, superstructure surface and top dielectric layer;Superstructure surface is laid on intermediate dielectric layer;Superstructure surface is equipped with nested octagon structure, nested octagon structure includes: with same centricity outer octagon ring, inner octagon ring and pattern based on regular polygon configuration;Inner octagon ring is sleeved outside geometric pattern;Outer octagon ring is sleeved outside inner octagon ring, and eight edges of outer octagon ring are parallel with eight edges of inner octagon ring respectively.The application can realize the selective absorption of terahertz energy in 0-8THz frequency range any multiple frequency band, while increasing the bandwidth of each absorption frequency band, so as to improve the absorption efficiency of energy and reduce loss.

Description

Technical Field

[0001] This invention belongs to the field of terahertz modulation technology, specifically relating to a multi-band terahertz energy harvester with a nested octagonal structure. Background Technology

[0002] Terahertz waves are electromagnetic waves with frequencies ranging from approximately 0.1 to 10 THz. With the continuous development of emerging terahertz science and technology, their applications have expanded to non-destructive testing, security inspection, radar detection, medical imaging, and broadband communications. Given the rich frequency information contained in the terahertz band, its unique spectral characteristics give it a significant advantage in accurately detecting tiny targets. Therefore, developing energy harvesting devices specifically designed for the terahertz band to fully utilize its high-frequency characteristics has become a crucial research task.

[0003] Currently, terahertz energy harvesting devices based on metasurfaces have been developed. These harvesters convert the energy of incident terahertz waves into other forms of energy and dissipate them by exciting localized surface plasmon resonances on the material surface, thereby achieving selective absorption of specific terahertz frequency bands.

[0004] Metasurfaces are a novel type of artificially designed material. As a two-dimensional form of metamaterial, a metasurface consists of a large number of periodically arranged subwavelength-scale metaunit structures. These metaunit structures can precisely control the propagation characteristics of electromagnetic waves, such as reflection, refraction, polarization, and phase. The emergence of metasurfaces provides unprecedented flexibility and precision in the manipulation of electromagnetic waves (i.e., the absorption of electromagnetic wave energy), making them promising for applications in sensing, non-destructive testing, and antennas. With advancements in materials science and micro / nano fabrication technologies, the design and fabrication of metasurfaces have become more feasible, opening up possibilities for their practical applications.

[0005] However, despite significant advancements in existing metasurface technology, terahertz energy harvesters still face several challenges in practical applications. Multi-band terahertz energy harvesters can increase selectivity, facilitating precise selection of the desired terahertz wave frequency band. However, current technologies have a limited range of terahertz wave frequencies that can be absorbed, and the bandwidth of each absorbable band is relatively narrow, directly impacting energy absorption efficiency, losses, and utilization.

[0006] In summary, there is an urgent need to conduct research on energy harvesting devices capable of multi-band terahertz absorption to meet the needs of fields such as energy harvesting, non-destructive testing, and super-resolution imaging. Summary of the Invention

[0007] In view of this, the present invention provides a multi-band terahertz energy harvester with a nested octagonal structure, which can selectively absorb terahertz energy in any number of frequency bands within the 0-8THz frequency range, while increasing the bandwidth of each absorption band, thereby improving energy absorption efficiency and reducing losses.

[0008] This invention is achieved through the following technical solution:

[0009] A multi-band terahertz energy harvester with a nested octagonal structure includes: several periodically arranged resonant cavities;

[0010] Each of the resonant cavities includes, from bottom to top, a reflective base plate, an intermediate dielectric layer, a metasurface, and a top dielectric layer;

[0011] The metasurface is laid on the intermediate medium layer; the metasurface is provided with a nested octagonal structure, which includes: an outer octagonal ring with the same centroid, an inner octagonal ring, and a pattern based on regular polygons.

[0012] An inner octagonal ring is placed outside the geometric pattern;

[0013] An outer octagonal ring is placed outside an inner octagonal ring, and the eight sides of the outer octagonal ring are parallel to the eight sides of the inner octagonal ring.

[0014] Furthermore, the outer periphery of the four inclined sides B of the outer octagonal ring has a stepped structure.

[0015] Furthermore, the inner circumferential surfaces of the four inclined sides A of the inner octagonal ring have a stepped structure.

[0016] Furthermore, the pattern in each resonant cavity can be any one of a regular octagon, a hexagon, or an eight-pointed star.

[0017] Furthermore, when the pattern is a six-pointed star, each apex angle is 60°.

[0018] Furthermore, when the pattern is an octagonal star, each vertex is 90°.

[0019] Furthermore, this includes: resonant cavities with two or more structural forms;

[0020] Different resonant cavities have different patterns.

[0021] Furthermore, the collection frequency band and the bandwidth of the corresponding frequency band can be adjusted by changing the array configuration, the pattern, or the surface resistance of the metasurface.

[0022] Beneficial effects:

[0023] (1) A multi-band terahertz energy harvester with a nested octagonal structure, wherein the metasurface is provided with a nested octagonal structure, the nested octagonal structure including a geometric pattern with the same centroid, an inner octagonal ring and an outer octagonal ring, the metasurface structure is simple and easy to fabricate, enabling the harvester to absorb multi-band terahertz energy in the frequency range of 0-8THz and increase the bandwidth of each corresponding frequency band, thereby improving the energy absorption efficiency, loss and utilization, so that the harvester can be applied to the fields of energy harvesting, non-destructive testing and super-resolution imaging; the top dielectric layer can further improve the absorption efficiency of terahertz energy; by using the nested octagonal structure to achieve selective absorption of terahertz energy in any number of frequency bands in the frequency range of 0-8THz, the bandwidth of each absorption frequency band is also increased, thereby improving the energy absorption efficiency and reducing loss.

[0024] (2) A multi-band terahertz energy collector with a nested octagonal structure, wherein the pattern is any one of regular octagon, hexagonal star and octagonal star, so that the collector can guarantee the absorption of terahertz energy in any three or more frequency bands within the 0-8THz frequency range.

[0025] (3) A multi-band terahertz energy collector with a nested octagonal structure, wherein the energy collector is any one of the following: a combination of resonant cavities with patterns of regular octagon and hexagonal star, a combination of resonant cavities with patterns of regular octagon and octagonal star, or a combination of resonant cavities with patterns of hexagonal star and octagonal star. By using two different resonant cavities with different patterns, the number of frequency bands collected can be further increased, and the resonant absorption of terahertz waves can be further enhanced.

[0026] (4) A multi-band terahertz energy harvester with a nested octagonal structure, the harvesting frequency band and the bandwidth of the corresponding frequency band can be adjusted by changing the array form, changing the pattern or changing the surface resistance of the metasurface, thereby realizing the research of energy harvesting devices with multi-band terahertz absorption. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural schematic diagram of the resonant cavity of the present invention (taking a regular octagonal structure as an example);

[0028] Figure 2 This is a front view of the resonant cavity of the present invention (the pattern is a regular octagonal structure);

[0029] Figure 3 This is a periodic array diagram of the metasurface of the present invention (the pattern is a regular octagonal structure);

[0030] Figure 4 The electromagnetic wave resonance absorption characteristic curve of this invention in the terahertz band (the surface resistance of the metasurface is 100Ω / sq, and the pattern is a regular octagonal structure);

[0031] Figure 5 The electromagnetic wave resonance absorption characteristic curve of the present invention in the terahertz band (the surface resistance of the metasurface is 80Ω / sq, and the pattern is a regular octagonal structure);

[0032] Figure 6 This is a front view of the resonant cavity of the present invention (the pattern is a six-pointed star structure);

[0033] Figure 7 This is a periodic array diagram of the metasurface of the present invention (the pattern is a hexagonal star structure);

[0034] Figure 8 This is a graph showing the electromagnetic wave resonance absorption characteristics of the present invention in the terahertz band (the pattern is a six-pointed star structure).

[0035] Figure 9 This is a front view of the resonant cavity of the present invention (the pattern is an octagonal star structure);

[0036] Figure 10 This is a periodic array diagram of the metasurface of the present invention (the pattern is an octagonal star structure);

[0037] Figure 11 This is a graph showing the electromagnetic wave resonance absorption characteristics of the present invention in the terahertz band (the pattern is an octagonal star structure).

[0038] Figure 12 This is a periodic array pattern of the metasurface of the present invention (a mixture of resonant cavities with a hexagonal pattern and a regular octagonal pattern);

[0039] Figure 13 The electromagnetic wave resonant absorption characteristic curve of the present invention in the terahertz band (a mixture of a resonant cavity with a hexagonal pattern and a resonant cavity with a regular octagonal pattern);

[0040] Among them, 1-reflective base plate, 2-intermediate dielectric layer, 3-meta-surface, 4-top dielectric layer, 5-outer octagonal ring, 6-inner octagonal ring, 7-pattern. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] Example 1:

[0043] This embodiment provides a multi-band terahertz energy harvester with a nested octagonal structure, consisting of a number of resonant cavities arranged periodically, i.e., the resonant cavities are arranged in an m×n array, where m represents the number of rows and n represents the number of columns, and both m and n are arbitrary natural numbers. Each pair of adjacent resonant cavities is fitted together.

[0044] like Figure 1 As shown, each resonant cavity includes: a reflective base plate 1, an intermediate dielectric layer 2, a metasurface 3, and a top dielectric layer 4.

[0045] In actual use, it is not required that the reflective base plate 1 is located at the bottom.

[0046] The reflective substrate 1 is a conductive thin film with a surface resistivity of 13Ω / sq.

[0047] The intermediate dielectric layer 2 is disposed above the reflective substrate 1 and is an FEP film (i.e., fluorinated ethylene propylene copolymer film) with a dielectric constant of 2.1.

[0048] The metasurface 3 is laid on the intermediate dielectric layer 2. The metasurface 3 has a nested octagonal structure located in the middle of the intermediate dielectric layer 2; the nested octagonal structure includes: an outer octagonal ring 5 with the same centroid, an inner octagonal ring 6, and a pattern 7 based on a regular polygon.

[0049] In this embodiment, the pattern 7 is preferably one of a regular octagon, a hexagonal star, and an eight-pointed star.

[0050] The inner octagonal ring 6 is fitted around the pattern 7, and the centroids of the two are the same. The inner octagonal ring 6 has four sides that are parallel to the four sides of the intermediate dielectric layer 2, which are called the positive sides A, and the sides other than the four positive sides are called the hypotenuses A. The inner circumferential surfaces of the four hypotenuses A of the inner octagonal ring 6 are stepped.

[0051] The outer octagonal ring 5 is fitted over the inner octagonal ring 6, and their centroids are the same. The eight sides of the outer octagonal ring 5 are parallel to the eight sides of the inner octagonal ring 6. Let the four hypotenuses of the outer octagonal ring 5 (corresponding to the four hypotenuses A of the inner octagonal ring 6) be hypotenuses B, and the sides other than the four hypotenuses B be regular sides B. The outer circumference of the four hypotenuses B of the outer octagonal ring 5 is stepped.

[0052] The top dielectric layer 4 is disposed above the metasurface 3 and is an FEP thin film with a dielectric constant of 2.1.

[0053] In this embodiment, the pattern of the metasurface 3 is formed by laser etching. Specifically, the metasurface 3 includes a substrate material and a resistive dielectric layer (such as indium tin oxide, ITO) disposed on the substrate material. The resistive dielectric layer is burned off by laser etching technology to remove excess structural areas (i.e., the parts not shown in the figure), leaving nested octagonal structures.

[0054] By changing the array configuration, pattern 7, surface resistance of metasurface 3, or structural parameters of metasurface 3 (such as the dimensions of the outer and inner circumferential surfaces of the positive and hypotenuse sides B of the outer octagonal ring 5, and the dimensions of the outer and inner circumferential surfaces of the positive sides A and B of the inner octagonal ring 6), the collection frequency band and response bandwidth can be adjusted.

[0055] As an example, the terahertz energy harvester includes two or more resonant cavities with different patterns 7. These patterns can be: a combination of a resonant cavity with a regular octagonal pattern 7 and a resonant cavity with a hexagonal pattern 7; or a combination of a resonant cavity with a regular octagonal pattern 7 and a resonant cavity with an octagonal pattern 7; or a combination of a resonant cavity with a hexagonal pattern 7 and a resonant cavity with an octagonal pattern 7. By using two different resonant cavities with different patterns 7, the number of frequency bands collected can be further increased, and the resonant absorption of terahertz waves can be further enhanced.

[0056] Example 2:

[0057] Based on Example 1, such as Figure 3 As shown, this embodiment provides a multi-band terahertz energy harvester with a nested octagonal structure, used to absorb multiple terahertz frequency bands in the 0-8THz frequency range.

[0058] In this embodiment, the thickness of the reflective base plate 1 of each resonant cavity is 2μm; the thickness of the intermediate dielectric layer 2 and the top dielectric layer 4 is 26μm; and the thickness of the metasurface 3 is 2μm.

[0059] In this embodiment, the pattern 7 of each metasurface 3 is a regular octagon.

[0060] Each metasurface 3 has a nested octagonal structure ( Figure 2 The specific dimensions are as follows:

[0061] The periodic array period of the metasurface 3 of the resonant cavity (i.e., the side length of one metasurface 3) is x = 200 μm;

[0062] Other structural parameters: L1 = 150 μm, L2 = 96 μm, L3 = 9 μm, L4 = 10.5 μm, L5 = 9 μm, L6 = 53.4 μm, L7 = 46 μm, L8 = 36 μm, L10 = 9 μm, L11 = 10.5 μm, L9 = 60 μm;

[0063] in,

[0064] L1 is the distance between the outer periphery of the two opposite positive sides B of the outer octagonal ring 5;

[0065] L2 is the length of the outer periphery of each positive side B of the outer octagonal ring 5;

[0066] L3 is the width of each step face of the stepped structure of each hypotenuse B of the outer octagonal ring 5;

[0067] L4 is the distance between the outer and inner circumferential surfaces of each positive side B of the outer octagonal ring 5;

[0068] L5 is the distance between the inner circumferential surface of the outer octagonal ring 5 and the outer circumferential surface of the inner octagonal ring 6.

[0069] L6 is the length of the inner circumference of each positive side B of the outer octagonal ring 5;

[0070] L7 is the length of the outer perimeter of each positive side A of the inner octagonal ring 6;

[0071] L8 is the length of the inner circumference of each positive side A of the inner octagonal ring 6;

[0072] L9 is the distance between two opposite sides of a regular octagon when pattern 7 is a regular octagon;

[0073] L10 is the width of each step face of the stepped structure of each hypotenuse A of the inner octagonal ring 6;

[0074] L11 is the distance between the outer and inner surfaces of each positive side A of the inner octagonal ring 6.

[0075] When the surface resistance of metasurface 3 is 100Ω / sq, such as Figure 4 As shown, the absorber in this embodiment can absorb three terahertz wave frequency bands: 0.76-2.03THz, 4.66-5.39THz, and 6.09-6.91THz. The total absorption bandwidth of the terahertz frequency band is 2.82THz, which means it can collect terahertz energy in multiple frequency bands and increase the bandwidth of the absorbable frequency band, thereby enhancing the resonant absorption of terahertz waves.

[0076] When the surface resistance of metasurface 3 is 80 Ω / sq, such as Figure 5 As shown, the absorber in this embodiment can absorb electromagnetic waves in four terahertz frequency bands: 0.80-1.41THz, 1.66-2.13THz, 4.69-5.38THz, and 6.10-6.91THz, and the total bandwidth of the terahertz wave is 2.58THz.

[0077] Example 3:

[0078] Based on Example 1, such as Figure 7 As shown, this embodiment provides a multi-band terahertz energy harvester with a nested octagonal structure, used to absorb multiple terahertz frequency bands in the 0-8THz frequency range.

[0079] In this embodiment, the thickness of the reflective base plate 1 of each resonant cavity is 2μm; the thickness of the intermediate dielectric layer 2 and the top dielectric layer 4 is 26μm; and the thickness of the metasurface 3 is 2μm.

[0080] In this embodiment, the pattern 7 of each metasurface is a hexagram, and each vertex of the hexagram is 60°. That is, the shape of the hexagram is formed by the overlapping of two equilateral triangles with the same center.

[0081] Each metasurface 3 has a nested octagonal structure ( Figure 6 The specific dimensions are as follows:

[0082] The periodic array period of the metasurfaces of the resonant cavity (i.e., the side length of one metasurface 3) is x = 200 μm;

[0083] Other structural parameters: L1 = 150 μm, L2 = 96 μm, L3 = 9 μm, L4 = 10.5 μm, L5 = 9 μm, L6 = 53.4 μm, L7 = 46 μm, L8 = 96 μm, L10 = 9 μm, L11 = 10.5 μm, D1 = 69.3 μm;

[0084] in,

[0085] L1 is the distance between the outer periphery of the two opposite positive sides B of the outer octagonal ring 5;

[0086] L2 is the length of the outer periphery of each positive side B of the outer octagonal ring 5;

[0087] L3 is the width of each step face of the stepped structure of each hypotenuse B of the outer octagonal ring 5;

[0088] L4 is the distance between the outer and inner circumferential surfaces of each positive side B of the outer octagonal ring 5;

[0089] L5 is the distance between the inner circumferential surface of the outer octagonal ring 5 and the outer circumferential surface of the inner octagonal ring 6.

[0090] L6 is the length of the inner circumference of each positive side B of the outer octagonal ring 5;

[0091] L7 is the length of the outer perimeter of each positive side A of the inner octagonal ring 6;

[0092] L8 is the length of the inner circumference of each positive side A of the inner octagonal ring 6;

[0093] L10 is the width of each step face of the stepped structure of each hypotenuse A of the inner octagonal ring 6;

[0094] L11 is the distance between the outer and inner circumferential surfaces of each positive side A of the inner octagonal ring 6;

[0095] D1 is the side length of each equilateral triangle that forms the hexagon when pattern 7 is a hexagon.

[0096] When the surface resistivity of the metasurface is 100Ω / sq, such as Figure 8 As shown, the absorber in this embodiment can absorb three terahertz wave frequency bands: 0.74-1.96THz, 4.63-5.38THz, and 6.15-6.91THz. The total absorption bandwidth of the terahertz frequency band is 2.73THz, which means it can collect terahertz energy in multiple frequency bands and increase the bandwidth of the absorbable frequency band, thereby enhancing the resonant absorption of terahertz waves.

[0097] Example 4:

[0098] Based on Example 1, such as Figure 10 As shown, this embodiment provides a multi-band terahertz energy harvester with a nested octagonal structure, used to absorb multiple terahertz frequency bands in the 0-8THz frequency range.

[0099] In this embodiment, the thickness of the reflective base plate 1 of each resonant cavity is 2μm; the thickness of the intermediate dielectric layer 2 and the top dielectric layer 4 is 26μm; and the thickness of the metasurface 3 is 2μm.

[0100] In this embodiment, the pattern 7 of each metasurface 3 is an octagonal star, and each vertex of the octagonal star is 60°. That is, the shape of the octagonal star is formed by the overlap of two squares with the same center.

[0101] Nested octagonal structures on each metasurface ( Figure 9 The specific dimensions are as follows:

[0102] The periodic array period of the metasurfaces of the resonant cavity (i.e., the side length of one metasurface 3) is x = 200 μm;

[0103] Other structural parameters: L1 = 150 μm, L2 = 96 μm, L3 = 9 μm, L4 = 10.5 μm, L5 = 9 μm, L6 = 53.4 μm, L7 = 46 μm, L8 = 96 μm, L10 = 9 μm, L11 = 10.5 μm, D2 = 40 μm;

[0104] in,

[0105] L1 is the distance between the outer periphery of the two opposite positive sides B of the outer octagonal ring 5;

[0106] L2 is the length of the outer periphery of each positive side B of the outer octagonal ring 5;

[0107] L3 is the width of each step face of the stepped structure of each hypotenuse B of the outer octagonal ring 5;

[0108] L4 is the distance between the outer and inner circumferential surfaces of each positive side B of the outer octagonal ring 5;

[0109] L5 is the distance between the inner circumferential surface of the outer octagonal ring 5 and the outer circumferential surface of the inner octagonal ring 6.

[0110] L6 is the length of the inner circumference of each positive side B of the outer octagonal ring 5;

[0111] L7 is the length of the outer perimeter of each positive side A of the inner octagonal ring 6;

[0112] L8 is the length of the inner circumference of each positive side A of the inner octagonal ring 6;

[0113] L10 is the width of each step face of the stepped structure of each hypotenuse A of the inner octagonal ring 6;

[0114] L11 is the distance between the outer and inner circumferential surfaces of each positive side A of the inner octagonal ring 6;

[0115] D2 is the side length of each square forming the octagon when pattern 7 is an octagonal star.

[0116] When the surface resistivity of the metasurface is 100Ω / sq, such as Figure 11 As shown, the absorber in this embodiment can absorb four terahertz wave frequency bands: 0.85-1.38THz, 1.77-1.98THz, 4.63-5.39THz, and 6.06-6.89THz. The total absorption bandwidth of the terahertz frequency band is 2.33THz, which means it can collect terahertz energy in multiple frequency bands and increase the bandwidth of the absorbable frequency band, thereby enhancing the resonant absorption of terahertz waves.

[0117] Example 5:

[0118] like Figure 12 As shown, this embodiment provides a multi-band terahertz energy harvester with a nested octagonal structure. Based on embodiment 2, this embodiment further incorporates the technical solution in embodiment 3. That is, the harvester in this embodiment simultaneously adopts the resonant cavity with pattern 7 as a regular octagon in embodiment 2 and the resonant cavity with pattern 7 as a hexagon in embodiment 3.

[0119] When the two resonant cavities are arranged in a two-dimensional staggered pattern, and the surface resistance of the metasurface 3 of both resonant cavities is 100Ω / sq, as follows: Figure 13As shown, the absorber can absorb terahertz wave frequencies in four bands: 0.76-1.44THz, 1.66-2.03THz, 4.66-5.38THz, and 6.13-6.92THz, with a total absorption bandwidth of 2.56THz. This means it can collect terahertz energy across multiple bands, increase the bandwidth of the absorbable frequency band, and enhance the resonant absorption of terahertz waves.

[0120] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-band terahertz energy harvester with a nested octagonal structure, characterized in that, include: Several periodically arranged resonant cavities; Each of the resonant cavities includes, from bottom to top, a reflective base plate (1), an intermediate dielectric layer (2), a metasurface (3), and a top dielectric layer (4); The metasurface (3) is laid on the intermediate medium layer (2); the metasurface (3) is provided with a nested octagonal structure, which includes: an outer octagonal ring (5) with the same centroid, an inner octagonal ring (6) and a pattern (7) based on regular polygon construction. An inner octagonal ring (6) is fitted over a pattern (7) constructed based on a regular polygon; The outer octagonal ring (5) is fitted over the inner octagonal ring (6), and the eight sides of the outer octagonal ring (5) are parallel to the eight sides of the inner octagonal ring (6); The inner octagonal ring (6) has four sides that are parallel to the four sides of the intermediate dielectric layer (2). Let these four sides be positive sides A, and let the sides other than these four sides be hypotenuses A. The inner circumferential surface of the four hypotenuses A of the inner octagonal ring (6) has a stepped structure. Let the four hypotenuses corresponding to the four hypotenuses A of the outer octagonal ring (5) and the inner octagonal ring (6) be hypotenuses B. The outer periphery of the four hypotenuses B of the outer octagonal ring (5) has a stepped structure.

2. The multi-band terahertz energy harvester with a nested octagonal structure as described in claim 1, characterized in that, The pattern (7) in each resonant cavity based on a regular polygonal structure is any one of a regular octagon, a hexagonal star, or an octagonal star.

3. The multi-band terahertz energy harvester with a nested octagonal structure as described in claim 2, characterized in that, When the pattern (7) constructed based on regular polygons is a hexagram, each vertex is 60°.

4. The multi-band terahertz energy harvester with a nested octagonal structure as described in claim 2, characterized in that, When the pattern (7) constructed based on regular polygons is an octagonal star, each vertex is 90°.

5. The multi-band terahertz energy harvester with a nested octagonal structure as described in claim 1, characterized in that, include: Resonant cavities with two or more structural forms; The patterns (7) based on regular polygon constructions of resonant cavities with different structural forms are different.

6. A multi-band terahertz energy harvester with a nested octagonal structure as described in any one of claims 1-5, characterized in that, The collection band and the bandwidth of the corresponding band can be adjusted by changing the array configuration, changing the pattern (7) based on the regular polygon construction, or changing the surface resistance of the metasurface (3).

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