A magnetic field detection device based on terahertz wave absorption

Abstract

The present invention relates to the field of magnetic field detection technology, and specifically relates to a magnetic field detection device based on terahertz wave absorption, which includes a substrate, a topological insulator layer, and a magnetostrictive material. The topological insulator layer is disposed on the substrate, a cavity is provided on the surface of the topological insulator layer, and the magnetostrictive material fills the cavity. During application, the detection device is placed in the environment to be measured, a terahertz source emits terahertz waves, the terahertz waves irradiate the detection device of the present invention, and magnetic field detection is realized through the change of the transmitted terahertz waves. Since terahertz waves have high penetration ability, the present invention separates the sensing substance from the excitation source and the detector, and can realize non-contact magnetic field detection, and has good application prospects in the field of magnetic field detection.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic field detection, and particularly relates to a magnetic field detection device based on terahertz wave absorption. Background Art

[0002] High-precision magnetic field detection technology is an important part of modern detection technology. High-precision magnetic detection technology is widely applied in fields such as marine monitoring, aviation anti-submarine detection, earthquake prediction, and geomagnetic matching navigation.

[0003] Current magnetic field detection technologies are mainly based on the Hall effect, magnetoresistance effect, fluxgate effect, etc. The principle of the Hall effect is that under the action of a magnetic field, free electrons gather on both sides of the sensing material, thus forming a potential difference. The principle of the magnetoresistance effect is that under the action of a magnetic field, the resistance of some metals or semiconductors changes. The principle of the fluxgate effect is that under the action of a magnetic field, there is a non-linear relationship between the magnetic induction intensity and the magnetic field intensity of a high-permeability iron core. In these detection technologies, an external circuit needs to be connected to the sensing material, and non-contact detection cannot be achieved, which is inconvenient to use.

[0004] Terahertz (THz) waves refer to electromagnetic waves with frequencies in the range of 0.1 - 10 THz (wavelengths of 3000 - 30 microns). The wavelength of terahertz waves is longer than that of visible light, and it has high transmittance and relatively low energy. Terahertz waves have good penetrability for many dielectric materials and non-polar substances. In addition, the photon energy of terahertz waves is low, only 4.1 meV, which is very safe for the human body and organisms. Therefore, using the change in the absorbed energy of terahertz waves to achieve magnetic field detection is expected to realize non-contact magnetic field detection, that is, the sensing material is only placed in the magnetic field to be measured, while the terahertz wave source and the terahertz detector are not placed in the magnetic field to be measured. Summary of the Invention

[0005] To solve the above problems, the present invention provides a magnetic field detection device based on terahertz wave absorption, including a substrate, a topological insulator layer, and a magnetostrictive material. The topological insulator layer is placed on the substrate, and there is a cavity on the surface of the topological insulator layer, and the magnetostrictive material fills the cavity. In the magnetic field to be measured, the magnetic field causes the magnetostrictive material to expand, and the magnetostrictive material presses the topological insulator layer, thereby changing the surface plasmon resonance characteristics of the topological insulator layer, and realizing magnetic field detection through the change in the surface plasmon resonance characteristics of the topological insulator layer.

[0006] Furthermore, the material of the substrate is alumina. Terahertz waves can penetrate alumina, which is convenient for detecting the transmitted terahertz waves.

[0007] Furthermore, the material of the topological insulator layer is bismuth selenide.

[0008] Furthermore, the cavity is circular.

[0009] Furthermore, the cavity does not penetrate the topological insulator layer. In this way, the topological insulator layer in contact with the magnetostrictive material has a larger contact area. When the magnetostrictive material expands, the surface state of the topological insulator layer changes more, thereby changing the localized surface plasmon resonance of the topological insulator layer more, thereby achieving higher sensitivity magnetic field detection.

[0010] Furthermore, the distance between the bottom of the cavity and the bottom of the topological insulator layer is less than 200 nanometers, and further, the distance between the bottom of the cavity and the bottom of the topological insulator is less than 100 nanometers. In this way, the expansion of the magnetostrictive material can change the surface state of the topological insulator material at the bottom of the cavity more, thereby changing the localized surface plasmon resonance of the topological insulator layer more, and achieving higher sensitivity magnetic field detection.

[0011] Furthermore, the magnetostrictive material is a giant magnetostrictive material.

[0012] Furthermore, the giant magnetostrictive material is TbDyFe material.

[0013] Furthermore, the cavities are arranged periodically.

[0014] Furthermore, the period of the cavity arrangement is a square period.

[0015] Beneficial effects of the present invention: The present invention provides a magnetic field detection device based on terahertz wave absorption, comprising a substrate, a topological insulator layer, and a magnetostrictive material, wherein the topological insulator layer is placed on the substrate, a cavity is provided on the surface of the topological insulator layer, and the magnetostrictive material fills the cavity. When applied, the detection device is placed in a test environment, a terahertz source emits terahertz waves, and the terahertz waves irradiate the detection device of the present invention, forming surface plasmon resonance on the surface of the topological insulator layer and in the cavity; the magnetic field to be measured changes the size of the magnetostrictive material, and the magnetostrictive material compresses the topological insulator material on the side and bottom of the cavity, changing the surface state of the topological insulator material, thereby changing the surface plasmon resonance of the topological insulator layer, generating different degrees of absorption of the terahertz wave, and realizing magnetic field detection through the change of the transmitted terahertz wave. Since the terahertz wave has a high penetration ability, the present invention separates the sensing material from the excitation source and the detector, and can realize non-contact magnetic field detection, which has good application prospects in the field of magnetic field detection. In the present invention, the magnetostrictive material not only changes the surface state of the topological insulator layer, but also changes the morphology of the cavity, so the present invention also has the advantage of high magnetic field detection sensitivity.

[0016] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a schematic diagram of a magnetic field detector based on terahertz wave absorption.

[0018] Figure 2 It is a schematic diagram of another magnetic field detector based on terahertz wave absorption.

[0019] Figure 3 It is a schematic diagram of yet another magnetic field detector based on terahertz wave absorption.

[0020] In the figure: 1. Substrate; 2. Topological insulator layer; 3. Cavity. Detailed implementation manner

[0021] For the purpose, technical solution and advantages of the present application to be more clearly understood, the following examples are given with reference to the accompanying drawings to further elaborate on the present application in detail.

[0022] Example 1

[0023] The present invention provides a magnetic field detection device based on terahertz wave absorption. As Figure 1As shown, the magnetic field detection device based on terahertz wave absorption includes a substrate 1, a topological insulator layer 2, and a magnetostrictive material. The material of the substrate 1 is alumina, that is, aluminum trioxide. Terahertz waves can penetrate alumina, facilitating the detection of transmitted terahertz waves. The topological insulator layer 2 is disposed on the substrate 1. The material of the topological insulator layer 2 is a topological insulator material. Specifically, the material of the topological insulator layer 2 is bismuth selenide or bismuth telluride. A topological insulator is an electromagnetic substance with novel optical properties. The interior of the topological insulator is in an insulating state, and the surface is metallic. This metallicity stems from the spin of surface electrons. A cavity 3 is provided on the surface of the topological insulator layer 2. The cavity 3 does not penetrate the topological insulator layer 2. In this way, the topological insulator layer 2 in contact with the magnetostrictive material has a larger contact area. When the magnetostrictive material expands, the surface state of the surface of the topological insulator layer 2 changes more, thus changing the local surface plasmon resonance of the topological insulator layer 2 more, thereby achieving high-sensitivity magnetic field detection. The cavity 3 is circular. The cavities 3 are arranged periodically. The period of the arrangement of the cavities 3 is a square period. The magnetostrictive material fills the cavity 3. The magnetostrictive material is a giant magnetostrictive material (GMM). At room temperature, due to the change in the magnetization state, the length and volume of the giant magnetostrictive material change significantly. That is to say, the giant magnetostrictive material has an extremely large magnetostrictive coefficient. In addition, the giant magnetostrictive material has a high heat-resistant temperature and strong magnetostrictiveness, which is conducive to changing the surface state of the topological insulator material on the side wall and the bottom of the cavity 3 in the present invention. Furthermore, at room temperature, the giant magnetostrictive material can achieve a high conversion efficiency between mechanical energy and magnetic energy, has a large energy density, a fast response speed, and good reliability, and is very suitable for application in the present invention. The giant magnetostrictive material can be a TbDyFe material, a TbFe2 material, a DyFe2 material, a SmFe2 material, etc.

[0024] During application, the detection device is placed in the environment to be measured. A terahertz source emits terahertz waves, and the terahertz waves irradiate the detection device of the present invention, forming surface plasmon resonance on the surface of the topological insulator layer 2 and inside the cavity 3; the magnetic field to be measured changes the size of the magnetostrictive material, and the magnetostrictive material compresses the topological insulator material on the side and bottom of the cavity 3, changing the surface state of the topological insulator material, thereby changing the surface plasmon resonance of the topological insulator layer 2 and generating different degrees of absorption of terahertz waves. Magnetic field detection is achieved through the change in transmitted terahertz waves. Since terahertz waves have high penetration ability, the present invention separates the sensing substance from the excitation source and the detector, enabling non-contact magnetic field detection and having good application prospects in the field of magnetic field detection. In the present invention, the magnetostrictive material not only changes the surface state of the topological insulator layer 2 but also changes the morphology of the cavity 3. Therefore, the present invention also has the advantage of high magnetic field detection sensitivity.

[0025] Example 2

[0026] Based on Example 1, the distance between the bottom of the cavity 3 and the bottom surface of the topological insulator layer 2 is less than 200 nanometers. Further, the distance between the bottom of the cavity 3 and the bottom surface of the topological insulator layer 2 is less than 100 nanometers. In this way, the expansion of the magnetostrictive material can more significantly change the surface state of the topological insulator material at the bottom of the cavity 3, thereby more significantly changing the local surface plasmon resonance of the topological insulator layer 2, and achieving higher-sensitivity magnetic field detection.

[0027] Example 3

[0028] Based on Example 2, as Figure 2 shown, the cavity 3 is inclined. In Figure 2 , the bottom of the cavity 3 is inclined to the right. When the magnetostrictive material in the cavity 3 expands, the pressures on the surfaces of the topological insulator layer 2 on the left and right sides of the cavity 3 are different. Especially near the cavity 3, different forces are generated on the surface of the topological insulator layer 2, thereby changing the coupling between the surface of the topological insulator layer 2 and the side wall of the cavity 3, significantly changing the local surface plasmon resonance of the entire topological insulator layer 2, and thus more significantly changing the absorption of terahertz waves and the terahertz transmission spectrum, so as to achieve higher-sensitivity magnetic field detection.

[0029] Example 4

[0030] Based on Example 3, as Figure 3 shown, the bottom of the cavity 3 is thick and the top of the cavity 3 is thin. In this way, more magnetostrictive material is arranged in the cavity 3, and a stronger terahertz light field can also be confined in the cavity 3, thereby exerting a stronger extrusion on the side wall of the cavity 3, thus more significantly changing the absorption of terahertz waves, and thus more significantly changing the terahertz transmission spectrum, in order to achieve higher-sensitivity magnetic field detection. In addition, this example can also have a greater impact on the surface state of the surface of the topological insulator layer 2, thereby more significantly changing the local surface plasmon resonance of the entire topological insulator layer 2, and thus achieving higher-sensitivity magnetic field detection.

[0031] Example 5

[0032] Based on Embodiment 4, the top of the magnetostrictive material is flush with the surface of the topological insulator layer 2. An alumina layer is provided on the surface of the topological insulator layer 2 and the magnetostrictive material. Since terahertz waves can penetrate the alumina layer, setting the alumina layer on the surface of the topological insulator layer 2 and the magnetostrictive material does not hinder the terahertz waves from exciting the topological insulator layer 2 to generate localized surface plasmon resonance. The alumina layer covers the magnetostrictive material. When the magnetostrictive material expands, the compressive force on the side wall of the cavity 3 is greater, and the surface state of the topological insulator material on the side wall of the cavity 3 changes more, thereby achieving higher-sensitivity magnetic field detection. In addition, the alumina layer also plays a protective role, and the surfaces of the topological insulator layer 2 and the magnetostrictive material are not easily damaged by the external environment or operation, improving the device life.

[0033] Embodiment 6

[0034] Based on Embodiment 5, a second topological insulator layer is provided on the surface of the topological insulator layer 2 and the magnetostrictive material, and an alumina layer is provided on the second topological insulator layer. The material of the second topological insulator layer can be the same as or different from the material of the topological insulator layer 2. The thickness of the second topological insulator layer is less than 100 nanometers. In this way, when the magnetostrictive material expands, it also squeezes the second topological insulator layer. Since the second topological insulator layer is very thin, it can change the surface state of the second topological insulator layer more, thereby changing the localized surface plasmon resonance of the composite structure composed of the second topological insulator layer and the topological insulator layer 2 more, and thus changing the absorption of terahertz waves by the composite structure more, generating more changes in the transmitted terahertz waves, thereby achieving higher-sensitivity magnetic field detection. In addition, the alumina layer also plays a protective role, and the surfaces of the topological insulator layer and the magnetostrictive material are not easily damaged by the external environment or operation, improving the device life.

[0035] Furthermore, the thickness of the second topological insulator layer is less than 50 nanometers, so that more terahertz waves can be coupled into the cavity 3 to form localized surface plasmon resonance in the cavity 3 and generate more absorption of the incident terahertz waves. In this way, when the magnetostrictive material expands, the absorption of terahertz waves changes more, thereby achieving higher-sensitivity magnetic field detection.

[0036] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the scope of protection of the present application.

Claims

1. A magnetic field detection device based on terahertz wave absorption, characterized in that, It includes a substrate, a topological insulator layer, and a magnetostrictive material. The topological insulator layer is disposed on the substrate. There is a cavity on the surface of the topological insulator layer. The bottom of the cavity is thick and the top of the cavity is thin. The magnetostrictive material fills the cavity. The cavity does not penetrate the topological insulator layer. The magnetic field to be measured changes the size of the magnetostrictive material. The magnetostrictive material presses the topological insulator material on the side and bottom surfaces of the cavity, changes the surface state of the topological insulator material, thereby changing the surface plasmon resonance of the topological insulator layer, and produces different degrees of absorption of terahertz waves. The magnetic field detection is realized through the change of the transmitted terahertz waves.

2. The magnetic field detection device based on terahertz wave absorption according to claim 1, wherein: The material of the substrate is alumina.

3. The magnetic field detection device based on terahertz wave absorption according to claim 1, characterized in that: The material of the topological insulator layer is bismuth selenide.

4. The magnetic field detection device based on terahertz wave absorption according to claim 1, characterized in that: The cavity is circular.

5. The magnetic field detection device based on terahertz wave absorption according to claim 1, characterized in that: The distance between the bottom of the cavity and the bottom surface of the topological insulator layer is less than 200 nanometers.

6. The magnetic field detection device based on terahertz wave absorption according to claim 1, wherein: The magnetostrictive material is a giant magnetostrictive material.

7. The magnetic field detection device based on terahertz wave absorption according to claim 6, wherein: The giant magnetostrictive material is a TbDyFe material.

8. The magnetic field detection device based on terahertz wave absorption according to claim 1, wherein: The cavities are arranged periodically.

9. The magnetic field detection device based on terahertz wave absorption according to claim 8, wherein: The period of the cavity arrangement is a square period.

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