A terahertz-tunable absorbing metasurface structure based on perovskite materials

Abstract

The present invention discloses a terahertz tunable absorbing metasurface structure based on perovskite materials, comprising a plurality of unit structures, which, from bottom to top, comprise a metal base plate, a dielectric substrate, a perovskite layer, and a metal structure etched on the perovskite layer. The metal structure comprises a circular ring and a cross inside the circular ring. The portion of the circular ring corresponding to the cross is provided with a protrusion, and the cross inside the circular ring is composed of two identical rectangular perpendicular intersections. By etching the metal structure on the perovskite layer, the perovskite layer located at the bottom layer can achieve tunable absorbing by changing the external excitation, achieving efficient absorption of electromagnetic waves in a specific frequency band without the need for an external power supply, thereby satisfying the convenience of the tunable absorbing device in practical applications. In addition, by setting the physical size and material parameters of the resonant unit, the reflection of the electromagnetic wave can be reduced, achieving efficient absorption of electromagnetic waves in a specific frequency band.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave absorption, and relates to a terahertz adjustable wave-absorbing metasurface structure based on perovskite materials. Background Art

[0002] With the development of terahertz technology, terahertz waves have shown great application prospects in fields such as security inspection, nondestructive testing, and wireless communications. Although terahertz technology has made rapid progress in light sources and detectors, further exploration and research are still needed compared to the mature infrared and microwave bands. Absorbing metasurfaces are a new type of artificial absorbing material that has been developed in recent years. Currently, the main approaches to achieving tunable absorbing metasurfaces include loading lumped components, liquid crystals, graphene, and microfluidics. The lumped component approach presents challenges with power feeding, complex manufacturing, and the fragility of lumped components. Tunable absorbers based on graphene and liquid crystals face difficulties in preparation and processing. Microfluidics approaches to achieve tunable absorbers have slow response speeds due to complex switching. Furthermore, these methods require an external power supply, which falls short of the practical requirements for effective, convenient, and cost-effective tunable absorbers. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems in the prior art that adjustable absorbing metasurfaces require an external power supply, are difficult to process in practical applications, and cannot meet the needs of efficient and convenient use, and to provide a terahertz adjustable absorbing metasurface structure based on perovskite materials.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A terahertz tunable absorbing metasurface structure based on perovskite material includes several unit structures. The unit structures include, from bottom to top, a metal base plate, a dielectric substrate, a perovskite layer, and a metal structure etched on the perovskite layer. The metal structure includes a ring and a cross inside the ring. The inside of the ring is provided with a protrusion at the part corresponding to the cross. The cross inside the ring is composed of two identical rectangles perpendicularly intersecting.

[0006] A further improvement of the present invention is:

[0007] The length and width of the metal bottom plate, dielectric substrate and perovskite layer are all 100 μm, the height of the metal bottom plate and perovskite layer are both 0.2 μm, and the height of the dielectric substrate is 100 μm.

[0008] The circular ring in the metal structure includes two concentric circles, an outer circle and an inner circle. The radius of the outer circle is 45 μm, and the radius of the inner circle is 40 μm.

[0009] The height of the metal structure etched on the perovskite layer is 0.2 μm.

[0010] The rectangular structure forming the inner cross in the metal structure has a length of 38.5 μm and a width of 4 μm.

[0011] The gap between the inner cross and the protrusion of the outer ring in the metal structure is 2 μm.

[0012] The unit structure is set to 100 to form a 10*10 terahertz tunable absorbing metasurface.

[0013] The perovskite layer is formed on a dielectric substrate by spin coating a CH3NH3PbI3 solution with a mass fraction of 10%.

[0014] The dielectric substrate is made of silicon dioxide with a dielectric constant of 3.5.

[0015] The metal base plate is made of gold, and the metal structure etched on the perovskite layer is made of gold.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention proposes a terahertz tunable absorbing metasurface structure based on perovskite materials. By etching a metal structure on the perovskite layer, the underlying perovskite layer can achieve adjustable absorption by changing the external excitation, thereby achieving efficient absorption of electromagnetic waves in a specific frequency band without the need for an external power supply, thus satisfying the convenience of adjustable absorbing devices in practical applications.

[0018] Furthermore, by setting the physical dimensions and material parameters of the resonant unit, the reflection of electromagnetic waves can be reduced, and efficient absorption of electromagnetic waves in a specific frequency band can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the metal structure etched on the perovskite layer in the present invention;

[0021] Figure 2 Graph showing the input matching of the absorbing metasurface under different perovskite conductivities in the present invention;

[0022] Figure 3This is a graph showing the absorptivity of the adjustable absorbing metasurface under different perovskite conductivities in the present invention. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0026] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0028] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0029] The present invention discloses a terahertz-tunable absorbing metasurface structure based on perovskite materials, which is composed of a plurality of unit structures, with 100 unit structures being provided to form a 10*10 terahertz-tunable absorbing metasurface. The unit structure comprises, from the bottom, a metal base plate, a dielectric substrate, a perovskite layer, and a metal structure etched on the upper surface of the perovskite layer. The length and width of the metal base plate, dielectric substrate, and perovskite layer are all 100 μm, the height of the metal base plate and perovskite layer are both 0.2 μm, and the height of the dielectric substrate is 100 μm; see Figure 1 , is a schematic diagram of a metal structure etched on a perovskite layer, the metal structure comprising a circular ring and a cross portion inside the circular ring, the height of the metal structure etched on the perovskite layer is 0.2 μm, a protrusion is provided at the portion corresponding to the cross inside the circular ring, the gap between the inner cross in the metal structure and the protrusion of the outer circular ring is 2 μm, the inner cross portion of the circular ring is composed of two identical rectangles perpendicularly crossed, the circular ring in the metal structure comprises two concentric circles, an outer circle and an inner circle, the outer circle radius is 45 μm, and the inner circle radius is 40 μm; the length of the rectangular structure forming the inner cross in the metal structure is 38.5 μm, and the width is 4 μm.

[0030] The perovskite layer is spin-coated onto a dielectric substrate using a 10% by mass CH₃NH₃PbI₃ solution, forming a thin perovskite film. The dielectric substrate is made of silicon dioxide with a dielectric constant of 3.5. The metal baseplate is made of gold, and the metal structure etched onto the perovskite layer is also made of gold. The perovskite layer is positioned beneath the metal pattern layer, ensuring that the perovskite can be adjusted by varying external stimuli while not restricting the design of the metal pattern. This high degree of freedom allows for the design of units of varying sizes and structures to achieve a variety of functions. The top metal structure pattern is highly sensitive to this wavelength band, enabling wide-range absorbance modulation.

[0031] The frequency domain solver of the electromagnetic simulation software CST MicrowaveStudio 2018 was used to simulate and optimize a metamaterial absorber using a terahertz-tunable metasurface structure. During the simulation, the terahertz wave was incident perpendicular to the metamaterial absorber surface, with the wave vector k along the z-axis, the electric field along the x-axis, and the magnetic field along the y-axis. Periodic and open boundary conditions were set on the XY and Z planes to simulate an infinite periodic array. Figure 2 , is the input matching curve of the absorbing metasurface under different perovskite conductivities in the present invention, Figure 2 Figure 1 shows the S11 of the designed absorbing metasurface with perovskite conductivity of 0, 500, and 1000 S / m. It can be clearly seen that the reflectivity decreases with the increase of perovskite conductivity. Figure 3As shown, this is a graph of the absorptivity of the adjustable absorbing metasurface under different perovskite conductivities in the present invention. At 1.17 THz, the reflection coefficient changes from -1.5 dB to -36.5 dB. In the absence of laser irradiation, the conductivity of the perovskite is 0, and the absorptivity of the absorber at 1.17 THz is only 0.27. Due to the photovoltaic properties of perovskite, under lower laser irradiation, the conductivity of the perovskite can be increased to 500 S / m, and the absorptivity reaches 0.94. Under strong laser irradiation, its conductivity reaches 1000 S / m, and the absorber can almost completely absorb. Therefore, the absorber using the terahertz adjustable absorbing metasurface structure of the present invention can achieve a large range modulation of 0.73 under laser irradiation of different intensities.

[0032] The present invention's perovskite-based terahertz tunable absorbing metasurface structure, by etching a metal structure onto the perovskite layer, enables the underlying perovskite layer to achieve tunable absorption by varying external excitation. This allows for efficient absorption of electromagnetic waves within specific frequency bands without requiring an external power source, ensuring the convenience of tunable absorbing devices in practical applications. Furthermore, by adjusting the physical dimensions and material parameters of the resonant unit, electromagnetic wave reflection can be reduced, achieving efficient absorption of electromagnetic waves within specific frequency bands.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A terahertz tunable absorbing metasurface structure based on perovskite material, characterized in that: The device comprises several unit structures, which include a metal base plate, a dielectric substrate, a perovskite layer and a metal structure etched on the perovskite layer from bottom to top. The metal structure includes a ring and a cross inside the ring. A protrusion is provided in the part inside the ring corresponding to the cross. The cross inside the ring is composed of two identical rectangles vertically crossed.

2. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The length and width of the metal bottom plate, dielectric substrate and perovskite layer are all 100 μm, the height of the metal bottom plate and perovskite layer are both 0.2 μm, and the height of the dielectric substrate is 100 μm.

3. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The circular ring in the metal structure includes two concentric circles, an outer circle and an inner circle. The radius of the outer circle is 45 μm, and the radius of the inner circle is 40 μm.

4. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The height of the metal structure etched on the perovskite layer is 0.2 μm.

5. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The rectangular structure forming the inner cross in the metal structure has a length of 38.5 μm and a width of 4 μm.

6. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The gap between the inner cross and the protrusion of the outer ring in the metal structure is 2 μm.

7. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The unit structure is set to 100 to form a 10*10 terahertz tunable absorbing metasurface.

8. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The perovskite layer is formed on a dielectric substrate by spin coating a CH3NH3PbI3 solution with a mass fraction of 10%.

9. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The dielectric substrate is made of silicon dioxide with a dielectric constant of 3.

5.

10. The terahertz tunable absorbing metasurface structure based on perovskite material according to claim 1, characterized in that: The metal base plate is made of gold, and the metal structure etched on the perovskite layer is made of gold.

Images