An ultrahigh-sensitivity terahertz metamaterial sensor device and a preparation method thereof

Abstract

The application discloses an ultrahigh-sensitivity terahertz metamaterial sensor device and a preparation method, and belongs to the technical field of terahertz metamaterial biochemical sensing. The structure comprises: a plasmonic gold film substrate and a metamaterial pattern structure. The metamaterial pattern structure is deposited on the surface of the plasmonic gold film substrate, and a unit cell thereof is composed of a vertical split resonator and a horizontal intermediate connector. The vertical split resonator is composed of two gold square column resonators, and the intermediate connector is composed of a two-dimensional material graphene nanosheet. Under the vertical incidence excitation of TM terahertz waves, the vertical split resonator and the horizontal intermediate connector can realize high-intensity electric field coupling, and output ultrahigh detection sensitivity and high quality factor. The application has the advantages of simple structure and easy preparation, and provides detection sensitivity in the THz / RIU order, which is much higher than the performance of current terahertz sensor devices, and can effectively solve the practical problems of the current terahertz sensor devices, such as complex structure, poor detection sensitivity and low quality factor.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of terahertz metamaterial biochemical sensing, and particularly relates to an ultrahigh-sensitivity terahertz metamaterial sensor device and a preparation method thereof. BACKGROUND

[0002] Unlike natural materials, metamaterials are artificially designed materials with negative refractive index and have unique optoelectronic properties. At present, the main form of metamaterials is a periodic arrangement of structural units at the subwavelength scale. When the periodic structural units at the subwavelength level match the TM terahertz wave of a specific frequency, plasmonic resonance occurs, resulting in strong local electric field enhancement and greatly improving the terahertz sensing and detection capability. Sensitivity and quality factor (Q value) are two criteria for measuring the performance of terahertz metamaterial sensor devices. High detection sensitivity usually indicates that the metamaterial structure has significant local electric field enhancement capability, while high Q value means that the metamaterial has less photon energy loss and is more sensitive to weak super surface signal changes. Therefore, a metamaterial structure with high detection sensitivity and high Q value undoubtedly has a wide range of application scenarios. At present, terahertz metamaterial sensor devices mainly have the following shortcomings: 1) it is difficult to simultaneously obtain high sensitivity and high Q value; 2) the structure is complex and difficult to process and prepare. SUMMARY

[0003] The present application aims to solve the shortcomings of existing terahertz metamaterial sensor devices and proposes an ultrahigh-sensitivity terahertz metamaterial sensor device and a preparation method thereof. The mutual coupling between the vertical resonator array and the parallel connector produces a significant terahertz resonance absorption peak, has ultrahigh detection sensitivity and high Q value, and can be used for terahertz ultra-sensitive quantitative detection.

[0004] To achieve the above-mentioned purpose, the present application provides the following scheme: an ultrahigh-sensitivity terahertz metamaterial sensor device, comprising: a plasmonic gold film substrate and a periodic metamaterial pattern structure.

[0005] The metamaterial pattern structure comprises a plurality of unit cells arranged periodically; the unit cells are deposited on the surface of the plasmonic gold film substrate.

[0006] Further preferably, the unit cells are composed of vertical split resonators and horizontal intermediate connectors;

[0007] The vertical split resonator comprises two square column resonators;

[0008] The horizontal intermediate connector is composed of a two-dimensional material graphene nanosheet.

[0009] Further preferably, the period width of the metamaterial pattern structure ranges from 3 to 5 microns;

[0010] The distance between two adjacent unit cells is 1.4 μm;

[0011] The material of the plasmonic gold film substrate is gold, and the thickness ranges from 0.1 μm to 0.5 μm.

[0012] Further preferably, the material of the square column resonator is gold, and the height and the width are the same, the height ranges from 0.7 μm to 1 μm, and the width ranges from 0.3 μm to 0.5 μm.

[0013] The material of the connector between the two square column resonators is graphene, the thickness ranges from 0.1 μm to 0.3 μm, and the width ranges from 0.7 μm to 0.9 μm.

[0014] Further preferably, under the vertical incidence excitation of TM terahertz waves, the vertical split column resonator and the horizontal intermediate connector resonate to generate a terahertz resonance absorption peak.

[0015] The terahertz resonance absorption peak exhibits a blue shift phenomenon by changing the optical refractive index of the surface of the sensor device.

[0016] The application further provides a preparation method of the ultra-high-sensitivity terahertz metamaterial sensor device.

[0017] S1, a layer of plasmonic gold film is evaporated on the surface of a silica support substrate by a physical vapor deposition method to obtain the plasmonic gold film substrate.

[0018] S2, square column resonators are deposited on the surface of the plasmonic gold film by a physical vapor deposition method.

[0019] S3, a graphene nanosheet is deposited in the gold square column resonators by a chemical vapor deposition method to obtain the sensor device.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] Under the vertical incidence excitation of TM terahertz waves, the vertical split column resonator and the horizontal intermediate connector can realize high-intensity electric field coupling, and the sensor device structure proposed by the application can simultaneously output an ultra-high detection sensitivity (37.7 THz / RIU) and a high quality factor (Q value, 656.5), which are much higher than the performance (GHz / RIU) of the current terahertz sensor device, and effectively expand the application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the present application, the following briefly introduces the drawings needed in the embodiments. Obviously, the drawings described below only show some of the embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is a schematic diagram of an ultra-high sensitivity terahertz metamaterial sensor device model of an embodiment of the present application;

[0024] Figure 2 is a schematic diagram of a unit cell structure of a metamaterial pattern structure of an embodiment of the present application;

[0025] Figure 3 is a front view and a top view of the magnetic field energy distribution of a metamaterial pattern structure of an embodiment of the present application;

[0026] Figure 4 is a schematic diagram of the refractive index curve change of a metamaterial sensor device of an embodiment of the present application;

[0027] Figure 5 is a frequency shift fitting curve diagram of a metamaterial sensor device of an embodiment of the present application;

[0028] Figure 6 is a schematic diagram of the resonance absorption peak change of a metamaterial sensor device with different biochemical analyte thicknesses of an embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0031] Embodiment one:

[0032] As shown in the drawings, Figure 1 The present embodiment provides an ultra-high sensitivity terahertz metamaterial sensor device, which comprises: a plasmonic gold film substrate and a periodic metamaterial pattern structure; wherein the metamaterial pattern structure comprises a plurality of periodically arranged unit cells; the unit cells are deposited on the surface of the plasmonic gold film substrate, and the distance between two adjacent unit cells is 1.4 μm.

[0033] AsFigure 2 As shown, the period p width of the metamaterial pattern structure ranges from 3μm to 5μm; the plasma gold film substrate is made of gold, and the thickness w varies from 0.1μm to 0.5μm.

[0034] A further implementation is that the unit cell is composed of vertically arranged resonators and horizontal intermediate connectors; the vertically arranged resonators include two square column resonators; the horizontal intermediate connector is composed of a two-dimensional material graphene nanosheet.

[0035] The two square cylindrical resonators are made of gold, with the same height and width. The height h1 varies from 0.7μm to 1μm, and the width g varies from 0.3μm to 0.5μm. The connector between the two square cylindrical resonators is made of graphene, with the thickness h2 varying from 0.1μm to 0.3μm and the width d varying from 0.7μm to 0.9μm.

[0036] Further implementation lies in, such as Figure 3 As shown, under the vertical incident excitation of TM terahertz waves, the vertically arranged resonators and the horizontal intermediate connector exhibit a strong resonant coupling effect, thereby enhancing the local electric field, which is an important support for improving detection sensitivity.

[0037] like Figure 4 As shown, under vertical incident excitation of a TM terahertz wave, the vertically arranged resonator and the horizontal intermediate connector resonate, generating a terahertz resonant absorption peak. In air medium (n=1), the sensor exhibits a resonant absorption peak at a frequency of 105.04 THz and possesses a high Q value. According to the formula Q=F / FWHM, where F is the frequency of the resonant absorption peak and FWHM is the full width at half maximum (FWHM), the FWHM of the resonant absorption peak is 0.16 THz at 105.04 THz. Therefore, the Q value of the sensor is 656.5. The Q value is an important indicator of the performance of a terahertz sensor. A higher Q value indicates stronger frequency selectivity. Therefore, the sensor proposed in this invention solves the problem of low Q values ​​in traditional terahertz sensors.

[0038] Changing the optical refractive index (n = 1-2) of the sensor surface causes a significant blue shift in the terahertz resonance absorption peak. Different concentrations of biochemical molecules deposited on the sensor surface lead to varying degrees of change in the surface's optical refractive index. Therefore, this invention proposes a method for quantitatively calibrating the concentration of biochemical molecules based on the blue shift of the sensor's resonance absorption peak.

[0039] In the embodiment, 1 μm biochemical analyte is deposited on the surface of the sensor device, and the resonance absorption peak of the sensor device is blue-shifted, and the perfect linear relationship between the optical refractive index change of the sensing interface and the resonance absorption peak is shown. According to the linear fitting, the theoretical detection sensitivity of the sensor device can be obtained. In addition to the Q value, the sensitivity (S) of the sensor device is also an important indicator for evaluating the new sensor device. According to the formula S = △F / △n, the theoretical detection sensitivity of the sensor device is calculated. Wherein, △F is the blue shift amount of the resonance absorption peak, and △n is the optical refractive index change amount caused by the deposition of biochemical analyte with different concentrations on the surface of the sensor device. As shown in Figure 5 , through linear fitting, the sensitivity of the sensor device proposed in the application is 37.7 THz / RIU, which is much higher than the sensitivity of the conventional terahertz sensor device. Therefore, the application solves the practical problem of low sensitivity of the conventional terahertz sensor device.

[0040] As shown in Figure 6 , the terahertz metamaterial sensor device proposed in the embodiment can realize the measurement of biochemical molecular layers with different thicknesses. For the deposition of the biochemical analyte to be detected with an optical refractive index of 1.3 on the surface of the sensor device, when the thickness of the biochemical analyte is gradually adjusted from 0 μm to 2 μm, the resonance absorption peak is blue-shifted to different degrees. Moreover, it is not difficult to find that the amplitude of the change of the resonance absorption peak is relatively obvious, which indicates that the terahertz metamaterial sensor device proposed in the application has good detection performance.

[0041] Embodiment two

[0042] The embodiment provides a preparation method of an ultrahigh-sensitivity terahertz metamaterial sensor device, which comprises the following steps:

[0043] S1, a layer of plasmonic gold film is evaporated on the surface of a silicon dioxide support substrate by a physical vapor deposition method to obtain the plasmonic gold film substrate.

[0044] S2, a square column resonator is deposited on the surface of the plasmonic gold film by a physical vapor deposition method.

[0045] S3, a graphene nanosheet is deposited in the middle of the gold square column resonator by a chemical vapor deposition method to obtain the sensor device.

[0046] Specifically, the sensor device comprises a 0.1 μm plasmonic gold film substrate, a metamaterial pattern structure with a period of 3 μm, two gold square column resonators with a height (h1) of 0.7 μm and a width (g) of 0.3 μm, and a graphene connector with a thickness (h2) of 0.1 μm and a width (d) of 0.7 μm. The preparation method comprises the following steps:

[0047] First, a 0.1 μm plasmonic gold film is evaporated on the surface of a silicon dioxide support substrate by a physical vapor deposition method.

[0048] Secondly, gold square column resonators (height h1 is 0.7 μm, width g is 0.3 μm) are deposited on the gold film by physical vapor deposition.

[0049] Finally, graphene nanosheet layers with a thickness (h2) of 0.1 μm and a width (d) of 0.7 μm are deposited in the middle of the gold square column resonators by chemical vapor deposition.

[0050] The above-described embodiments are only descriptions of the preferred modes of the present application, and are not intended to limit the scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those of ordinary skill in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. An ultra-high sensitivity terahertz metamaterial sensor device, characterized by, The application relates to a sensor device, which comprises the following steps: S1, a physical vapor deposition method is used to evaporate a layer of plasmonic gold film on the surface of a silicon dioxide support substrate, so as to obtain a plasmonic gold film substrate; S2, a physical vapor deposition method is used to deposit square column resonators on the surface of the plasmonic gold film; S3, a chemical vapor deposition method is used to deposit a graphene nanometer thin layer in the middle of the gold square column resonators, so as to obtain the sensor device. The application relates to a sensor device, which comprises the following steps: S1, a physical vapor deposition method is used to evaporate a layer of plasmonic gold film on the surface of a silicon dioxide support substrate, so as to obtain a plasmonic gold film substrate; S2, a physical vapor deposition method is used to deposit square column resonators on the surface of the plasmonic gold film; S3, a chemical vapor deposition method is used to deposit a graphene nanometer thin layer in the middle of the gold square column resonators, so as to obtain the sensor device. The application relates to a sensor device, which comprises the following steps: S1, a physical vapor deposition method is used to evaporate a layer of plasmonic gold film on the surface of a silicon dioxide support substrate, so as to obtain a plasmonic gold film substrate; S2, a physical vapor deposition method is used to deposit square column resonators on the surface of the plasmonic gold film; S3, a chemical vapor deposition method is used to deposit a graphene nanometer thin layer in the middle of the gold square column resonators, so as to obtain the sensor device. The application relates to a sensor device, which comprises the following steps: S1, a physical vapor deposition method is used to evaporate a layer of plasmonic gold film on the surface of a silicon dioxide support substrate, so as to obtain a plasmonic gold film substrate; 2. A method for fabricating an ultra-high sensitivity terahertz metamaterial sensor device for implementing the sensor device of claim 1, characterized in that, S2, a physical vapor deposition method is used to deposit square column resonators on the surface of the plasmonic gold film; S3, a chemical vapor deposition method is used to deposit a graphene nanometer thin layer in the middle of the gold square column resonators, so as to obtain the sensor device. The application relates to a sensor device, which comprises the following steps: S1, a physical vapor deposition method is used to evaporate a layer of plasmonic gold film on the surface of a silicon dioxide support substrate, so as to obtain a plasmonic gold film substrate; S2, a physical vapor deposition method is used to deposit square column resonators on the surface of the plasmonic gold film; S3, a chemical vapor deposition method is used to deposit a graphene nanometer thin layer in the middle of the gold square column resonators, so as to obtain the sensor device. The application relates to a sensor device, which comprises the following steps: S1, a physical vapor deposition method is used to evaporate a layer of plasmonic gold film on the surface of a silicon dioxide support substrate, so as to obtain a plasmonic gold film substrate; S2, a physical vapor deposition method is used to deposit square column resonators on the surface of the plasmonic gold film; S3, a chemical vapor deposition method is used to deposit a graphene nanometer thin layer in the middle of the gold square column resonators, so as to obtain the sensor device. The application relates to a sensor device, which comprises the following steps: S1, a physical vapor deposition method is used to evaporate a layer of plasmonic gold film on the surface of a silicon dioxide support substrate, so as to obtain a plasmonic gold film substrate; S2, a physical vapor deposition method is used to deposit square column resonators on the surface of the plasmonic gold film; S3, a chemical vapor deposition method is used to deposit a graphene nanometer thin layer in the middle of the gold square column resonators, so as to obtain the sensor device.

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