A single-open split-ring resonator metamaterial terahertz biochemical sensor

Abstract

The present invention discloses a single - aperture split - ring resonator metamaterial terahertz biochemical sensor, belonging to the technical field of terahertz sensors. The sensor includes a dielectric substrate and metal single - aperture split - ring resonators arranged periodically on the dielectric substrate; the aperture of the metal single - aperture split - ring resonator includes one or more metal interdigital structures; when the metal single - aperture split - ring resonator is a square ring, the aperture is located on the arm of the square ring parallel to the electric field direction of the electromagnetic wave; when the metal single - aperture split - ring resonator is a circular ring, the tangential direction of the aperture is parallel to the electric field direction of the electromagnetic wave. By introducing metal interdigital structures at the aperture of the single - aperture split - ring resonator structure, the sensor of the present invention has a high quality factor Q, sensitivity S, and figure of merit FOM, and is particularly suitable for trace detection of biochemical analytes.

Description

Technical Field

[0001] The present invention belongs to the technical field of terahertz sensors, and more specifically, relates to a single-open resonator metamaterial terahertz biochemical sensor. Background Art

[0002] Terahertz waves (0.1 THz - 10 THz) have the advantages of non-ionizing radiation, the ability to penetrate non-metallic materials, and specific recognition. In particular, terahertz waves can capture changes in biomolecules, be used to study their structures, conformational changes, and interactions, and can detect various biomolecules, including amino acids, proteins, nucleic acids, sugars, etc. Therefore, through the interaction with terahertz waves, changes in the presence, thickness, dielectric constant, density, size, or chemical composition of a substance can cause changes in the polarization, intensity, frequency, and phase of terahertz signals. Terahertz sensors utilize these changes to invert and analyze changes in analytes, with frequency change sensors being the main research and application direction. However, natural materials have a weak response to terahertz waves, and traditional terahertz sensors have problems such as low detection sensitivity, low signal-to-noise ratio, and large volume.

[0003] Metamaterials are an artificially designed periodic structure with sub-wavelength dimensions. Through the design of structure, material, and size, they can achieve a strong resonant response to electromagnetic waves in the microwave, terahertz, infrared, and visible light bands. Among them, metal metamaterials have one or more resonant modes and have a high electric field enhancement factor and a small mode volume at the resonant frequency. Therefore, metal metamaterials can interact with trace non-magnetic analytes to produce a strong resonant frequency change. Terahertz sensors designed based on metal metamaterials have the potential to achieve highly sensitive analyte detection in the terahertz band and have a smaller volume, higher signal-to-noise ratio, and higher sensing sensitivity values.

[0004] The main parameters for measuring the resonant performance of metamaterials include the working mode and working frequency (resonant frequency), resonant intensity, quality factor Q (or full width at half maximum FWHM), electric field strength, and distribution law, etc. Terahertz sensors designed using metal metamaterials can achieve ultra-high sensitivity analyte detection in the terahertz band and have obvious advantages in terms of signal-to-noise ratio. In addition, they adopt a miniaturized design, greatly reducing the volume of the sensor, making it more compact, easy to carry, and use. The main performance parameters of terahertz sensors include the refractive index sensitivity S (the resonant frequency change caused by a unit refractive index change of the analyte) and the figure of merit FOM (equal to S / FWHM).

[0005] The split ring resonator (SRR) metallic metamaterial is the earliest proposed and most widely studied open-type metamaterial structure. By reducing the opening width, the electric field strength and the corresponding sensing sensitivity can be improved. For example, in Reference 1 [W. Withayachumnankul, H. Lin, K. Serita et al., Sub-diffraction thin-film sensing with planar terahertz metamaterials, Optics Express, 20(3), 3345-3352, 2012], the LC resonance mode (0.4 THz, Q = 40) of the SRR metamaterial with an opening width of 5 μm was used to perform sensing tests on an analyte (S1818G type photoresist, refractive index n = 1.6 - j0.02) with a thickness of 2.17 μm, and the refractive index sensitivity S = 8.1 GHz / RIU. In Reference 2 [M. Islam, S. J. M. Rao, G. Kumar et al., Role of Resonance Modes on Terahertz Metamaterials based Thin Film Sensors, Scientific Reports, 7(1), 7355, 2017], the sensing performances of the SRR metamaterial with an opening width of 4 μm at different incident electric field polarization directions were compared. There were three resonance modes, namely LC resonance (0.5 THz), electric dipole resonance (1.16 THz), and electric quadrupole resonance (1.47 THz). When the thickness of the analyte (relative permittivity of 3.5) was 20 μm, the LC resonance had the highest FOM value (0.42 RIU -1 ), while the electric quadrupole mode had the highest sensitivity (S = 0.14 THz / RIU). In Reference 3 [S. J. Park, S. H. Cha, G. A. Shin et al., Sensing viruses using terahertz nano-gap metamaterials, Biomedical Optics Express, 8(8), 3551-3558, 2017], the equivalent refractive index measurement and sensing analysis of two different sizes of dried uniform virus layers, 30 nm and 60 nm, were carried out using the electric split ring resonator (eSRR) metamaterial structure. When the opening width of the eSRR was reduced from 3 μm to 200 nm, the concentration sensitivity of virus sensing increased by 13 times.

[0006] According to Document 4 [L. Cao, S. S. Jia, M. D. Thomson et al., Can a terahertz metamaterial sensor be improved by ultra-strong coupling with a high-Q photonic resonator?, Optics Express, 30(8), 13659 - 13672, 2022], the relative change in the resonant frequency caused by placing a metamaterial resonant structure in a non-magnetic analyte is:

[0007]

[0008] where \(E_0\) and \(H_0\) are the electric and magnetic field distributions in the resonator (volume \(V\)) before placing the analyte, \(\mu\) and \(\varepsilon\) are the permeability and permittivity of the dielectric medium filled in the resonator respectively, and \(\Delta\varepsilon\) is the change in the permittivity of the analyte (volume \(\Delta V\)) relative to the original dielectric medium filled in the resonator at its location. It can be seen that the actual frequency shift amount (sensitivity) caused by the analyte depends on the size of the analyte, the maximum electric field value (electric field gain factor), and the spatial distribution (volume integral) of the strong electric field.

[0009] Although reducing the opening width is the most direct way to achieve enhanced electric fields, when the SRR structure reduces the opening width, not only will it increase the complexity and cost of the manufacturing process, but also the spatial volume occupied by the strong electric field at the opening will decrease, and the interaction space with the analyte will also become smaller, thus restricting to a certain extent the rate of increase in the resonant frequency shift.

[0010] In addition, terahertz sensors based on metamaterials have shown excellent performance in terms of selectivity, speed, sample preparation convenience, label-free detection, non-destructiveness, etc. However, compared with existing mature and widely used biochemical analysis methods (infrared and Raman spectroscopy, fluorescence spectroscopy, mass spectrometry, chromatography, electrochemical sensing, enzyme-linked method, etc.), the detection sensitivity of terahertz sensors based on metamaterials still has a large disadvantage and cannot form a strong competitive or complementary relationship with existing biochemical analysis methods. Therefore, further improving the sensitivity of terahertz sensors and reducing the detection limit value are urgent tasks for realizing the application of such sensing methods. Summary of the Invention

[0011] Aiming at the above defects or improvement requirements of the prior art, the present invention provides a single-opening resonant ring metamaterial terahertz biochemical sensor, aiming to solve the technical problem of low sensitivity existing in the detection of trace substances in biochemical analytes by existing terahertz sensors.

[0012] To achieve the above object, according to one aspect of the present invention, a single - split - ring metamaterial terahertz biochemical sensor is provided, which includes a dielectric substrate and a split - ring array disposed on the dielectric substrate;

[0013] The split - ring array includes a plurality of single - split - rings arranged periodically, and metal interdigital structures are provided at the openings of all the single - split - rings.

[0014] Preferably, the period of the unit structure of the metamaterial terahertz biochemical sensor in the x - axis direction and the y - axis direction is Px = Py = 50 - 500 microns. Further preferably, when the single - split - ring is a square ring, its length in the x - axis direction and the y - axis direction is Nx = Ny = 50 - 300 microns, the metal line width is U = 2 - 20 microns, U2 = 2 - 20 microns, and the opening size is G = 2 - 20 microns.

[0015] Preferably, the material of the single - split - ring is gold, silver, copper, aluminum, nickel, chromium or titanium.

[0016] Preferably, the thickness of the single - split - ring is 100 - 500 nanometers. Further preferably, when the material of the single - split - ring is gold, the conductivity of the metal is 4.561×10^7 S / m.

[0017] Preferably, the single - split - ring is of a square - ring structure or a circular - ring structure;

[0018] When the single - split - ring is a single - split - SRR square - ring structure, the opening and the interdigital structure are provided on the upper arm or the lower arm;

[0019] When the single - split - ring is a single - split - eSRR square - ring structure, the opening and the interdigital structure are provided on the middle arm;

[0020] When the single - split - ring is a single - split - SRR circular - ring structure, the opening and the interdigital structure are provided on the upper semi - circle or the lower semi - circle;

[0021] When the single - split - ring is a single - split - eSRR circular - ring structure, the opening and the interdigital structure are provided on the middle arm.

[0022] Further preferably, the period of the unit structure of the metamaterial terahertz biochemical sensor in the x - axis direction and the y - axis direction is Px = Py = 160 microns. When the single - split - ring is a single - split - eSRR square - ring, its length in the x - axis direction and the y - axis direction is Nx = Ny = 95 microns, the metal line width at the opening is U = 13.8 microns, the metal line width in the area outside the opening is U2 = 9 microns; the opening size is G = 12 microns.

[0023] Preferably, the finger length L of the metal interdigital structure is 2 - 20 microns, the finger width W is 0.1 - 1 micron, and the inter-finger gap M is 0.1 - 1 micron. Further preferably, the finger length L of the metal interdigital structure is 11 microns, the finger width W is 0.6 micron, and the inter-finger gap M is 0.6 micron.

[0024] Preferably, the material of the dielectric substrate is fused silica, high-resistivity silicon, polyimide, polymethylpentane, polyethylene or polytetrafluoroethylene.

[0025] Preferably, the thickness of the dielectric substrate is D = 0.1 - 2 mm. Further preferably, when the material of the dielectric substrate is fused silica, the relative dielectric constant of the dielectric substrate is 3.75 + j 0.0015.

[0026] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0027] For a single split-ring resonator metamaterial terahertz biochemical sensor proposed by the present invention, when the electric field direction of the incident electromagnetic wave is parallel to the metal arm where the split is located, the transmission spectra of the existing single split-ring resonator (SRR and eSRR) metamaterial terahertz sensors exhibit symmetric LC resonances, with a relatively large resonance intensity, but a lower quality factor Q and a relatively small electric field amplitude at the split, which is not conducive to accurately resolving the position of the resonance frequency point and the tiny frequency shift during the experimental measurement process. On this basis, by introducing a metal interdigital structure at the split of the single split-ring resonator structure, when the electric field direction of the incident electromagnetic wave is parallel to the metal arm with the introduced metal interdigital structure, it still exhibits symmetric LC resonances. However, the metal metamaterial described in the present invention has a high Q value and an extremely strong and widely distributed electric field during resonance, and thus has a high sensitivity S and a figure of merit FOM, and is extremely suitable for trace sensing detection of analytes with an extremely thin thickness, an extremely low concentration, and an extremely small quantity. Description of the Drawings

[0028] Figure 1 is a three-dimensional structural schematic diagram of the unit structure of the single split-ring resonator metamaterial terahertz biochemical sensor according to the embodiment of the present invention, where Figure 1 in (a) is the unit structure of a single split-ring SRR square ring, Figure 1 in (b) is the unit structure of a single split-ring eSRR square ring;

[0029] Figure 2 is a two-dimensional structural schematic diagram of the unit structure of the single split-ring resonator metamaterial terahertz sensor with an interdigital structure according to the embodiment of the present invention;

[0030] Figure 3 is a two-dimensional structural schematic diagram of a single split-ring resonator with an interdigital structure according to the embodiment of the present invention, whereFigure 3 In (a), it is a single - slit SRR square - ring structure, Figure 3 in (b), it is a single - slit SRR circular - ring structure, Figure 3 in (c), it is a single - slit eSRR square - ring structure, Figure 3 and in (d), it is a single - slit eSRR circular - ring structure;

[0031] Figure 4 It is the simulation diagram of the power transmission spectrum of the single - slit resonator - ring metamaterial terahertz sensor in the embodiment of the present invention. Among them, Figure 4 in (a), it is the simulation diagram of the cross - finger SRR structure, Figure 4 and in (b), it is the simulation diagram of the cross - finger eSRR structure;

[0032] Figure 5 It is the simulation diagram of the electric - field distribution of the single - slit eSRR resonator - ring metamaterial terahertz sensor at resonance in the embodiment of the present invention. Among them, Figure 5 in (a), it is the simulation diagram of the existing single - slit eSRR resonator - ring, Figure 5 and in (b), it is the simulation diagram of the single - slit eSRR resonator - ring with a cross - finger structure;

[0033] Figure 6 It is the simulation diagram of the resonance - frequency offset of the single - slit resonator - ring metamaterial terahertz sensor in the embodiment of the present invention when placing analytes with different refractive indices. Among them, Figure 6 in (a), it is the simulation diagram of the cross - finger SRR structure, Figure 6 and in (b), it is the simulation diagram of the cross - finger eSRR structure;

[0034] Figure 7 It is the simulation diagram of the resonance - frequency offset of the single - slit resonator - ring metamaterial terahertz sensor in the embodiment of the present invention when placing DNA with different thicknesses. Among them, Figure 7 in (a), it is the simulation diagram of the cross - finger SRR structure, Figure 7 and in (b), it is the simulation diagram of the cross - finger eSRR structure;

[0035] Figure 8 It is the change diagram of the power transmission spectrum of the single - slit resonator - ring metamaterial terahertz sensor with a cross - finger structure in the embodiment of the present invention when changing the size of the periodic unit. Among them, Figure 8 in (a), it is the change diagram of the cross - finger SRR structure, Figure 8 and in (b), it is the change diagram of the cross - finger eSRR structure;

[0036] Figure 9It is a diagram showing the variation of the electric field gain factor when the finger gap of the single - opening eSRR resonator metamaterial terahertz sensor with a cross - finger structure in the embodiments of the present invention is changed. Detailed implementation manners

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] The present invention provides a single - opening resonator metamaterial terahertz biochemical sensor, which includes a dielectric substrate and metal single - opening resonator rings arranged periodically on the dielectric substrate; the opening of the metal single - opening resonator ring includes one or more metal cross - finger structures; when the metal single - opening resonator ring is a square ring, the single opening is located on an arm of the square ring parallel to the electric field direction of the electromagnetic wave; when the metal single - opening resonator ring is a circular ring, the tangential direction of the single opening is parallel to the electric field direction of the electromagnetic wave.

[0039] Figure 1 and Figure 2 respectively show the three - dimensional structure schematic diagram and two - dimensional plane schematic diagram of the unit structure of the single - opening resonator metamaterial terahertz sensor with a cross - finger structure in the embodiments of the present invention, including two types: cross - finger SRR and cross - finger eSRR. The substrate is fused silica, and on the substrate is a square ring made of gold. There is an opening in the upper arm (SRR) or the middle arm (eSRR) of the square ring, and the opening contains a periodic structure of cross - finger gold material. The specific parameters are: the unit period is Px = Py = 100 - 500 microns, the length of the square ring is Nx = Ny = 50 - 300 microns, the metal line width is U = 2 - 20 microns, U2 = 2 - 20 microns, the size of the square ring opening is G = 2 - 20 microns, the finger length of the metal cross - finger structure is L = 2 - 20 microns, the finger width is W = 0.1 - 1 micron, the finger gap M = 0.1 - 1 micron, the thickness of the fused silica substrate is D = 0.1 - 2 mm, the relative dielectric constant of the substrate is 3.75 + j 0.0015, the metal thickness is 100 - 500 nm, and the conductivity of the metal is 4.561×10^7 S / m.

[0040] Furthermore, in the preferred embodiments of the present invention, the single - opening resonator ring can be a single - opening square ring or a single - opening circular ring. Taking Figure 3 as an example, several structures are specifically listed as follows: as shown in (a) of Figure 3 it is a single - opening SRR square ring structure, and the opening and the cross - finger structure are located on the upper arm; asFigure 3 As shown in Fig. (b), it is a single - opening SRR circular - ring structure, with an arc - shaped opening and a cross - finger structure located in the upper semi - circle; as Figure 3 shown in Fig. (c), it is a single - opening eSRR square - ring structure, with an opening and a cross - finger structure located in the middle arm; as Figure 3 shown in Fig. (d), it is a single - opening eSRR circular - ring structure, with an opening and a cross - finger structure located in the middle arm.

[0041] Using the frequency - domain solver of CST MWS software to Figure 3 the SRR shown in Fig. (a) and Figure 3 the single - opening square - ring metamaterial sensor of eSRR shown in Fig. (c) were simulated. In this simulation, the structural parameters involved are: the unit period is Px = Py = 160 μm, the length of the SRR square - ring is Nx = Ny = 64.7 μm, the length of the eSRR square - ring is Nx = Ny = 95 μm, the width of the metal wire at the opening is U = 13.8 μm, the width of the metal wire outside the eSRR opening area is U2 = 9 μm, the size of the square - ring opening is G1 = G2 = 12 μm, the length of the fingers of the metal cross - finger structure is L = 11 μm, the width of the fingers is W = 0.6 μm, the gap between fingers is M = 0.6 μm, the thickness of the fused - silica substrate is D = 150 μm, the relative permittivity of the substrate is 3.75 + j0.0015, the thickness of the metal is 200 nm, the conductivity of the metal is 4.561×10^7 S / m, and the relationship between the power transmittance and frequency is as Figure 4 shown. The reference sensor refers to a single - opening metamaterial terahertz sensor without a cross - finger structure, and the sensor of the present invention refers to a single - opening metamaterial terahertz sensor with a cross - finger structure. For the convenience of parameter comparison, the resonance frequencies of all sensors are adjusted to 287 GHz. When the electromagnetic wave is perpendicularly incident and the electric - field direction is parallel to the metal arm where the opening is located, the fundamental - mode resonance of all structures is LC resonance. The Q - value of the resonance mode of the sensor of the present invention is significantly increased compared with the reference sensor, indicating that the cross - finger structure can significantly reduce the loss of the metamaterial structure (especially the radiation loss). The resonance intensity of the cross - finger eSRR structure is better than that of the cross - finger SRR structure and is easier to be distinguished during the experimental measurement process. Table 1 compares the performance parameters of the sensor of the present invention and the reference sensor. The Q - value of the cross - finger SRR structure is 2.5 times that of the corresponding reference structure, and the Q - value of the cross - finger eSRR structure is 5.8 times that of the corresponding reference structure.

[0042] Table 1 Performance parameters of the sensor of the present invention

[0043]

[0044] Figure 5It shows the electric field amplitude distribution in the plane of the upper surface of the metal at the fundamental mode resonance frequency of the reference eSRR sensor and the eSRR sensor of the present invention. The strong electric field of the reference eSRR sensor is mainly concentrated at the metal edge near the opening, while the strong electric field of the eSRR sensor of the present invention is mainly concentrated at the finger gaps of all interdigital structures. The strong electric field has a large spatial region and is evenly distributed. The electric field gain factor (the ratio of the maximum electric field amplitude to the incident electric field amplitude) is 5.1 times that of the reference eSRR sensor. Therefore, the structural design of the present invention has a stronger electric field amplitude and a wider strong electric field region, enabling highly sensitive sensing of trace analytes.

[0045] Figure 6 The change in the resonance frequency shift of the sensor of the present invention and the reference sensor when different refractive index materials (n = 1.2, 1.4, 1.6, 1.8, and 2.0) are placed on the metal surface is compared, where the thickness of the analyte material is 100 nanometers. Table 1 compares the sensitivity S (unit: GHz / RIU) and the figure of merit FOM (unit: RIU -1 ) of the sensor when the analyte thickness is 100 nanometers, where RIU is the refractive index unit (refractive index unit). The sensitivity of the sensor of the present invention is 11 times that of the reference sensor, and the sensor of the present invention has a high Q value. Therefore, its figure of merit is higher than that of the reference sensor. Specifically, the FOM value of the interdigital SRR structure is 28 times that of the reference SRR structure, and the FOM value of the interdigital eSRR structure is 59 times that of the reference eSRR structure. Compared with the interdigital SRR structure, the interdigital eSRR structure has a slightly lower Q value, similar sensitivity, and a slightly lower figure of merit.

[0046] Figure 7The offset changes of the resonant frequency of the sensor of the present invention and a reference sensor were compared when different thicknesses of materials (0.02, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 microns) were placed on the metal surface. The analyte material was DNA, and the relative permittivity was 2.6 + j 0.0026. The relationship between the resonant frequency offset and the analyte thickness was non-linear. As the analyte thickness increased, the frequency offset first increased rapidly, then increased slowly, and finally tended to saturate. Table 2 lists the relationship between the DNA thickness and the sensor frequency offset. When the DNA thickness was 50 nm, the frequency shift of the interdigital structure was 7.2 GHz, which was 12 times that of the reference structure. When the DNA thickness was 500 nm, the frequency shift of the interdigital SRR structure was 7.2 times that of the reference SRR structure, and the frequency shift of the interdigital eSRR structure was 6.8 times that of the reference eSRR structure. Therefore, the sensor of the present invention is particularly suitable for sensing tests of analytes with extremely thin thicknesses. In actual sensing applications, the analyte can completely cover the metamaterial surface, specifically bind to the entire metal surface, or even partially cover the metal surface, such as the surface of the interdigital structure. Table 3 compares the frequency shifts caused by 100-nm DNA covering different regions of the metamaterial. For the sensor of the present invention, the frequency shift caused by DNA covering the entire metal (excluding the gap between fingers) accounted for 20% of the total frequency shift when DNA was completely covered, and the frequency shift caused by DNA only covering the interdigital structure was the same as the frequency shift caused by DNA covering the entire metal, indicating that the strong electric field of the sensor structure of the present invention is all concentrated in the interdigital region, especially the gap between the fingers of the interdigital structure.

[0047] Table 2 Relationship between the thickness of the analyte (DNA) and the sensor frequency offset

[0048] Sensor 50 nm (GHz) 100 nm (GHz) 500 nm (GHz) 1 μm ((GHz) SRR (reference) 0.6 0.9 3.5 6.1 Interdigitated SRR (present invention) 7.2 11.0 25.1 28.0 eSRR (reference) 0.6 1.0 3.8 6.4 Interdigitated eSRR (present invention) 7.2 11.2 25.9 28.9

[0049] Table 3 Relationship between the placement position of the analyte (100-nm DNA) and the sensor frequency offset

[0050]

[0051] For the sensor of the present invention, the periodic unit size (Px = Py) determines the coupling degree (electrical coupling, magnetic coupling, or both) between adjacent metamaterial units, thereby affecting the resonant frequency and the surface current, electric field, and radiation loss of the metamaterial during resonance. Therefore, the periodic unit size can be used to adjust the resonant characteristics of the metamaterial. Figure 8The influence of different periodic unit sizes (Px = Py = 120 - 200 μm) on the power transmittance of the sensor of the present invention was compared. As the unit size increases, the resonance intensity decreases, the quality factor increases, but the variation law of the resonance frequency is different. Within the simulated range of periodic unit sizes, for the interdigital SRR structure, its resonance frequency decreases as the unit size increases, while for the interdigital eSRR structure, its resonance frequency increases as the unit size increases. Therefore, the resonance and sensing performance of the metamaterial sensor of the present invention can be fine-tuned by the unit size.

[0052] The performance of the metamaterial sensor of the present invention is closely related to its structural parameters, especially the interdigital gap width M of the interdigital structure. When other structural parameters remain unchanged, Figure 9 The relationship between the electric field gain factor between fingers at resonance and the interdigital gap width (M = 0.1 - 1 μm) is given. The electric field gain factor decreases rapidly as the interdigital gap increases. When M = 0.1 μm, the electric field gain factor is as high as 1897, while when M increases to 1 μm, the electric field gain factor rapidly decreases to 281. Therefore, reducing the interdigital gap is beneficial to increasing the electric field amplitude at metamaterial resonance, thereby greatly enhancing the sensing sensitivity, especially for extremely thin analytes, but at the same time it will increase the process implementation complexity and preparation cost, and generally requires the use of electron beam lithography technology.

[0053] A single-open resonator metamaterial terahertz biochemical sensor proposed by the present invention, compared with a single-open resonator metamaterial terahertz sensor without an interdigital structure, the sensor of the present invention has a high quality factor, a strong electric field amplitude and a large strong electric field distribution region. Therefore, the sensing sensitivity and the sensitivity value are greatly improved, and it can realize label-free, amplification-free, non-destructive, specific, fast ultra-high sensitivity trace sensing applications, especially for biochemical analytes with extremely thin thickness, extremely low concentration, extremely small quantity and extremely small size, such as glucose, amino acids, proteins, DNA, viruses, tumor markers, etc., and the metamaterial structure is compact, easy to manufacture and measure, and has a great application scope and commercial value.

[0054] Those skilled in the art can easily understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A single - split - ring resonator metamaterial terahertz biochemical sensor, characterized in that, It includes a dielectric substrate and a resonant ring array disposed on the dielectric substrate; The resonant ring array includes a plurality of single - split resonant rings arranged periodically, and metal cross - finger structures are provided at the openings of all the single - split resonant rings; The single - split resonant ring is a square - ring structure or a circular - ring structure; When the single - split resonant ring is a single - split SRR square - ring structure, the opening and the cross - finger structure are provided on the upper arm or the lower arm; When the single - split resonant ring is a single - split eSRR square - ring structure, the opening and the cross - finger structure are provided on the middle arm; When the single - split resonant ring is a single - split SRR circular - ring structure, the opening and the cross - finger structure are provided on the upper semi - circle or the lower semi - circle; When the single - split resonant ring is a single - split eSRR circular - ring structure, the opening and the cross - finger structure are provided on the middle arm; The finger length L of the metal cross - finger structure is 2 - 20 microns, the finger width W is 0.1 - 1 micron, and the inter - finger gap M is 0.1 - 2 microns.

2. The single - opening split - ring resonator metamaterial terahertz biochemical sensor according to claim 1, characterized in that, The period of the periodic unit structure of the metamaterial terahertz biochemical sensor in the x - axis direction and the y - axis direction is Px = Py = 50 - 500 microns.

3. The single-open-ring metamaterial terahertz biochemical sensor according to claim 1, characterized in that The material of the single - split resonant ring is gold, silver, copper, aluminum, nickel, chromium or titanium.

4. A single - opening split - ring resonator metamaterial terahertz biochemical sensor according to claim 1, characterized in that, The thickness of the single - split resonant ring is 100 - 500 nanometers.

5. A single - opening split - ring resonator metamaterial terahertz biochemical sensor according to claim 1, wherein, The material of the dielectric substrate is fused silica, high - resistivity silicon, polyimide, polymethylpentane, polyethylene or polytetrafluoroethylene.

6. The single - opening split - ring resonator metamaterial terahertz biochemical sensor according to claim 5, characterized in that, The thickness of the dielectric substrate is D = 0.1 - 2 millimeters.

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