An asymmetric dual-openings metal resonant pair-ring metasurface sensor

Abstract

The application discloses an asymmetric double-opening metal resonant pair ring metasurface sensor, which comprises a substrate, wherein a metasurface unit with a preset period length is arranged on the substrate; the metasurface unit comprises two rectangular resonant rings which are symmetrically arranged based on a preset symmetry line; the two rectangular resonant rings have a preset center spacing; the rectangular resonant ring has a preset side length and a preset line width; opposite side edges of the rectangular resonant ring are respectively provided with opening gaps with a preset width; and an asymmetry degree is arranged between the two opening gaps; wherein the asymmetry degree is the spacing between the central axes corresponding to the two opening gaps, and the central axes are perpendicular to the symmetry line. The application has the advantages of improved sensor sensitivity and satisfaction of high-precision detection requirements.

Description

Technical Field

[0001] This application relates to the field of biosensor technology, and in particular to an asymmetric double-opening metal resonant pair metasurface sensor. Background Technology

[0002] The terahertz (THz) band, with frequencies between microwaves and infrared radiation, typically refers to the range from 0.1 THz to 10 THz. Electromagnetic waves in this band are characterized by non-ionization, low scattering, low energy, and high penetration. Many biomolecules exhibit unique vibrational and rotational characteristics in the terahertz band, enabling terahertz waves to identify the "fingerprint" information of biomolecules and perform non-destructive and non-contact detection of trace substances. Terahertz metasurfaces are artificial materials with periodic structures capable of interacting with electromagnetic waves of specific frequencies (especially in the terahertz band). The basic units of metasurfaces are usually composed of micrometer- or nanometer-scale metals or dielectric materials. By precisely designing their geometry and arrangement, specific manipulation of electromagnetic waves can be achieved. Terahertz metasurfaces can significantly enhance the signal response of target molecules through local surface plasmon resonance effects. This enhancement is mainly manifested in two aspects: firstly, the ability to detect extremely low concentrations of biochemical substances; and secondly, the ability to identify weak molecular characteristic signals. Based on this principle, the sensing technology using metasurfaces can simultaneously achieve excellent detection sensitivity and significant target recognition specificity.

[0003] However, existing terahertz metasurface sensors still have several technical shortcomings, mainly due to the low sensitivity of traditional terahertz metasurface sensors, which limits their application in the detection of low-concentration biomolecules. Summary of the Invention

[0004] The main objective of this application is to provide an asymmetric double-opening metal resonant pair metasurface sensor, which aims to solve the technical problem of low sensitivity of existing terahertz metasurface sensors.

[0005] To achieve the above objectives, this application provides an asymmetric double-opening metal resonant pair metasurface sensor, comprising a substrate, on which a metasurface unit with a preset period length is disposed, the metasurface unit comprising two rectangular resonant rings symmetrically arranged based on a preset symmetry line, the two rectangular resonant rings having a preset center-to-center distance, the rectangular resonant rings having a preset side length and a preset linewidth, and openings with preset widths being formed on opposite sides of the rectangular resonant rings, with an asymmetry between the two openings; wherein, the asymmetry is the distance between the central axes corresponding to the two openings, and the central axes are perpendicular to the symmetry line.

[0006] Optionally, the asymmetry is 2-10 μm.

[0007] Optionally, the center-to-center spacing is 100 μm.

[0008] Optionally, the preset linewidth is 7μm.

[0009] Optionally, the preset width is 4μm and the preset side length is 40μm.

[0010] Optionally, the preset period length is: 90 μm on the x-axis and 190 μm on the y-axis; wherein the x-axis is parallel to the line of symmetry.

[0011] Optionally, the thickness of the substrate is 35 μm and the thickness of the metasurface unit is 200 nm.

[0012] Optionally, the substrate is made of polyimide and the metasurface unit is made of gold.

[0013] The beneficial effects that this application can achieve are as follows: This application includes a substrate on which a metasurface unit with a preset period length is disposed. The metasurface unit includes two rectangular resonant rings symmetrically arranged based on a preset symmetry line. The two rectangular resonant rings have a preset center-to-center distance. The rectangular resonant rings have a preset side length and a preset linewidth. The opposite two sides of the rectangular resonant rings are respectively provided with opening gaps of a preset width. An asymmetry is provided between the two opening gaps. The asymmetry is the distance between the central axes corresponding to the two opening gaps, and the central axis is perpendicular to the symmetry line. Based on the asymmetric dual-opening metal resonant pair metasurface sensor structure of this application, the asymmetry of the structure is achieved by deviating the opening gap from the vertical center position, i.e., setting the asymmetry. This complex structural design introduces resonant coupling between the two rectangular resonant rings, which can excite electric dipole resonance and quasi-BIC peak with low radiation loss. Through structural asymmetry, independent control and synergistic optimization of the dual resonant modes are realized, effectively exciting both electric dipole resonance and quasi-BIC resonance modes, resulting in a dual resonant metasurface sensor with high quality factor (Q>270) and high sensitivity (S>280 GHz / RIU), which can meet the requirements of high sensitivity and high precision sensing and detection. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0015] Figure 1 This is a schematic diagram of the structure of an asymmetric double-opening metal resonant pair ring metasurface sensor according to an embodiment of this application; Figure 2 This is a schematic diagram of the parametric structure of the metasurface unit in the embodiments of this application; Figure 3 Here are schematic diagrams of the transmission spectra of metasurface units based on different asymmetries d in the embodiments of this application ((a) d=0, (b) d=2μm). Figure 4 The diagram shows the electric field and surface current distribution of the metasurface unit at three locations: 1.561 THz, 1.796 THz (without breaking structural symmetry), and 1.796 THz (with breaking structural symmetry). Figure 5 This is a schematic diagram of the transmission spectrum of the metasurface unit under different asymmetries in the embodiments of this application; Figure 6 This is a schematic diagram showing the relationship between the Q value and resonance intensity of the quasi-BIC resonance peak as a function of asymmetry in an embodiment of this application. Figure 7 The center-to-center distance S between the two rectangular resonant rings in the embodiments of this application (i.e. Figure 7 a) and line width w (i.e. Figure 7 b) Schematic diagram of the influence on resonance characteristics; Figure 8 The center-to-center distance S between the two rectangular resonant rings in the embodiments of this application (i.e. Figure 8 a) and line width w (i.e. Figure 8 b) Schematic diagram showing the influence of the sensor's Q value; Figure 9 This is a schematic diagram of the transmission spectrum corresponding to the optimized metasurface unit in the embodiments of this application; Figure 10 This is a schematic diagram illustrating the influence of different refractive index analytes on the resonance peak of the metasurface unit in the embodiments of this application; Figure 11 This is a schematic diagram illustrating the influence of the refractive index of the analyte on the sensor's sensing characteristics in an embodiment of this application.

[0016] Figure label: 110 - substrate, 120 - rectangular resonant ring, 121 - opening gap.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0020] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0022] Example Reference Figures 1-2This embodiment provides an asymmetric double-opening metal resonant pair metasurface sensor, including a substrate 110. A metasurface unit with a preset period length (the period length determines the operating frequency range of the metasurface, thereby allowing for the design and analysis of the reflection performance of a terahertz metasurface for biochemical sensing detection) is disposed on the substrate 110. The metasurface unit includes two rectangular resonant rings 120 symmetrically arranged based on a preset symmetry line. A preset center distance exists between the two rectangular resonant rings 120. Each rectangular resonant ring 120 has a preset side length and a preset linewidth. Opening gaps 121 with preset widths are respectively opened on opposite sides of the rectangular resonant rings 120. An asymmetry is provided between the two opening gaps 121; wherein, the asymmetry is the distance between the central axes corresponding to the two opening gaps 121, and the central axes are perpendicular to the symmetry line.

[0023] Complex metasurface sensors offer significant advantages over simple metasurfaces in terms of quality factor and sensitivity. In terms of quality factor, complex sensors achieve higher Q values, stronger robustness, and enhanced multi-mode coupling. Regarding sensitivity, the complexity of the sensor structure allows for greater field localization on the metasurface, enhancing light-matter interactions, providing more sensing mechanisms, and exhibiting a higher surface state density. These characteristics result in superior sensing performance, making them highly promising and valuable in various sensing applications. They can meet the demands for high-sensitivity, high-precision sensing and detection, and drive the development of related fields.

[0024] Therefore, based on the above principles, the asymmetry of the sensor structure in this embodiment is achieved by deviating the opening gap 121 from the vertical center position, i.e., setting the asymmetry. This complex structural design introduces resonant coupling between the two rectangular resonant rings 120. When terahertz electromagnetic waves are incident perpendicularly from the sensor normal (i.e., the thickness direction), electric field polarization can be generated with the electric field polarization direction parallel to the sensor normal. It can also excite electric dipole resonance and BIC peak with low radiation loss. Through structural asymmetry, independent control and synergistic optimization of the dual resonant modes are achieved, effectively exciting both electric dipole resonance and quasi-BIC resonance modes, resulting in a high-quality factor and high-sensitivity dual resonant metasurface sensor, which can meet the requirements for high-sensitivity and high-precision sensing and detection.

[0025] It should be noted that the main performance indicators of terahertz sensors include: quality factor (Q), sensitivity (S), and FOM value. The quality factor (Q), through local electric field enhancement, can effectively improve the interaction between terahertz waves and matter, giving the sensor higher frequency selectivity. A higher Q value indicates a sharper resonance peak and lower energy loss. The Q value is defined as the ratio of the resonant frequency (f0) to the full width at half maximum (FWHM), calculated as: Q = f0 / FWHM. Sensitivity (S) reflects the sensor's ability to respond to small changes in the environment or the properties of the analyte. A higher S value indicates a more accurate detection of minute changes in the analyte. Refractive index sensitivity (S) is defined as the resonant frequency shift caused by a unit change in refractive index during sensing, usually expressed in GHz / RIU (frequency shift per unit change in refractive index), calculated as: S = Δf / Δn, where Δf and Δn are the refractive index change and the corresponding resonant frequency shift, respectively. To more comprehensively evaluate sensor performance, the Figure of Merit (FOM) is proposed as a comprehensive evaluation parameter. The FOM value quantifies the overall performance of the sensor by combining its sensitivity (S) and full width at half maximum (FWHM). The specific formula for calculating the FOM value is: FOM = S / FWHM.

[0026] To explain in detail the impact of metasurface unit geometry parameters on sensor performance, such as Figure 2 As shown, the initial geometric parameters of the metasurface unit are designed as follows: period length Px = 90 μm, Py = 190 μm, side length L = 40 μm of the rectangular resonant ring 120, center spacing S = 100 μm, linewidth w = 5 μm, opening gap width g = 4 μm, and asymmetry d is determined through optimization adjustment, here d is taken as 2-10 μm. Preferably, the substrate 110 is made of polyimide, which can reduce its absorption of terahertz waves, and the metasurface unit is made of gold. The transmission spectrum of the metasurface unit symmetry structure (d=0) was obtained by simulation calculation using electromagnetic simulation software, as shown below. Figure 3 As shown in (a). Also as... Figure 3 As shown in (b), the transmission spectrum of the metasurface unit that breaks the structural symmetry (d≠0) shows two sharp resonance valleys and quasi-BIC peaks at 1.561 THz and 1.796 THz, indicating that its quality factor is very high. This also reflects the advantage of complex metasurface structures compared to simple structures.

[0027] To analyze the generation mechanism of these two resonances, such as Figure 4As shown, the electric field distribution (a, b, and c represent the electric field distribution at different frequencies) and surface current distribution (d, e, and f represent the surface current distribution at different frequencies) at three locations: 1.561 THz, 1.796 THz (without breaking structural symmetry), and 1.796 THz (with breaking structural symmetry). Figure 4 As shown in (a) and (d), at 1.561 THz, electrons are mainly concentrated in the left half of the rectangular resonant ring 120. The same current on the surface of the two rectangular resonant rings 120 excites the electric dipole oscillation mode. Combined with the electric field distribution, the electric dipole mode can be seen more clearly. Figure 4 As shown in (b) and (e), at 1.796 THz without breaking the structural symmetry, the system is in BIC mode, with no energy leakage and no sharp linear peak in the spectrum. At this point, the surface current flows in the same direction, similarly exciting the electric dipole oscillation mode. Figure 4 As shown in (c) and (f), at the BIC peak at 1.796 THz where the structural symmetry is broken, the quasi-BIC state forms a ring current distribution, which is a magnetic dipole model.

[0028] Theoretical analysis shows that by breaking the symmetry of the metasurface unit structure, a quasi-BIC resonant mode with a high Q value can be introduced. Figure 5 The influence of asymmetry degree d on the quasi-BIC resonance characteristics is shown. When d = 0 μm, only one electric dipole resonance peak is observed in the transmission spectrum. When the asymmetry degree d ≠ 0 μm, the breaking of structural symmetry successfully excites the quasi-BIC resonance mode, and at this time, both electric dipole resonance and quasi-BIC resonance characteristic peaks exist simultaneously in the transmission spectrum. Meanwhile, as the asymmetry degree d increases, the center frequency of the electric dipole resonance remains stable, but the full width at half maximum (FWHM) of its resonance valley decreases significantly, and the sharpness of the resonance peak increases significantly. At the same time, the quasi-BIC resonance peak shows a broadening trend, the Q value gradually decreases, but its relative intensity shows a monotonically increasing characteristic. Table 1 below quantitatively presents the Q value and relative resonance intensity of the quasi-BIC resonance peak under different asymmetry degrees d, and their variation trends are as follows: Figure 6 As shown. Based on a comprehensive optimization consideration of Q value and relative resonance intensity, the optimal asymmetry d = 4 μm was finally determined.

[0029] Table 1. Influence of asymmetry d on the alignment BIC resonance characteristic parameters

[0030] To achieve the electric dipole effect and quasi-BIC effect with ultra-high Q values, this embodiment systematically optimizes the structural parameters of the metasurface unit. During optimization, the fixed parameters are: period length Px = 90 μm, Py = 190 μm, side length L = 40 μm of the rectangular resonant ring 120, width g = 4 μm of the opening gap, asymmetry d = 4 μm, substrate 110 thickness 35 μm, and metasurface unit thickness 200 nm. This embodiment focuses on the influence of two key parameters: (1) center-to-center spacing S (initial value 100 μm); (2) linewidth w (initial value 5 μm). Simulation results are as follows: Figure 7 As shown. Figure 7 (a) illustrates the influence of the center spacing S on the resonant characteristics. As the value of S increases, the spacing between the upper and lower rectangular resonant rings 120 decreases, leading to enhanced coupling effect of the unidirectional currents on the structural surface. This change causes two significant features: (i) a blue shift occurs in the electric dipole resonance valley, and the resonance width becomes significantly narrower; (ii) the quasi-BIC peak exhibits a red shift trend, and the resonance width gradually increases. When S = 100 μm, the quasi-BIC peak reaches its maximum amplitude. This is because the structural symmetry is optimally broken at this point, and the electric field is concentrated at the opening and both sides of the open ring, forming a strongly coupled ring current distribution. As the value of S continues to increase, the asymmetry between the ring structures weakens, the current coupling strength decreases, leading to the broadening and red shift of the quasi-BIC peak. Figure 7 (b) shows the effect of the metal linewidth w on the resonance characteristics. As the value of w increases, the resonance widths of both the electric dipole resonance valley and the quasi-BIC peak decrease, and the quasi-BIC peak undergoes a redshift. This phenomenon can be attributed to the change in the coupling strength between the metal structure and the incident wave: the increase in the metal linewidth w leads to an expansion of the electric field distribution region, which enhances the coupling effect, thereby making the resonance peak sharper.

[0031] Since the Q-value is also a key factor in evaluating resonance, the changes in the Q-values ​​of the two rectangular resonant rings 120 in the metasurface structure were simulated and analyzed by changing the center-to-center distance S and the linewidth w. Figure 8 As shown. It can be seen that, in Figure 8In (a), the Q value of the electric dipole resonance increases significantly with the increase of the center-to-center distance S between the two rectangular resonant rings 120. This is because as S increases, the distance between the two rectangular resonant rings 120 decreases, enhancing the coupling effect of the unidirectional currents excited by the electric field on the surface of the structure, thus narrowing the resonance width. Simultaneously, the electric dipole resonance valley gradually exhibits a blue shift. The electric dipole resonance valley reaches its maximum value at S = 100 μm, at which point the Q value is 408. Conversely, the quasi-BIC peak shows a gradual decrease in Q value with increasing S, reaching a maximum of 301 at S = 60 μm. This is because the quasi-BIC peak is introduced by breaking the symmetry of the metasurface structure. However, as S increases, the asymmetry between the two ring structures weakens, and the coupling strength between the currents gradually decreases, leading to an increase in the resonance width of the quasi-BIC transmission peak and a red shift. Figure 8 In (b), as the metal linewidth w gradually increases, the Q value of the electric dipole resonance shows an upward trend, reaching a maximum quality factor of 523 at w = 7 μm. The quasi-BIC peak also generally shows an upward trend, reaching a maximum quality factor of 244 at w = 6 μm, after which its Q value decreases slightly with increasing metal linewidth w. At w = 7 μm, the Q value is 223, not significantly different from that at w = 6 μm. This is because as w increases, the proportion of the metasurface unit structure on the substrate 110 increases, forming a stronger electromagnetic field localization, which enhances the localized field plasmon resonance on the metasurface, resulting in a sharper electric dipole resonance valley and quasi-BIC peak.

[0032] Therefore, based on the above optimization analysis, the optimal structural parameters of the sensor in this embodiment were determined as follows: number of periods Px = 90 μm, Py = 190 μm, side length L of rectangular resonant ring 120 = 40 μm, center distance S of two rectangular resonant rings 120 = 100 μm, linewidth w = 7 μm, opening gap g = 4 μm, asymmetry d = 4 μm, substrate 110 thickness is 35 μm, and metasurface unit thickness is 200 nm. Figure 9 The transmission spectrum corresponding to the metasurface unit after structural optimization is calculated under the optimal structure. An electric dipole resonance is formed at f1=1.561THz with a Q value of 385 and a relative resonance intensity of 0.40; a quasi-BIC peak is formed at f2=1.794THz with a Q value of 297 and a relative resonance intensity of 0.85.

[0033] Based on the requirements of subsequent solution sensing experiments, the sensitivity of the metasurface was theoretically calculated. In the numerical simulation, a 50-micrometer-thick layer of the test material was used as the metasurface capping layer. The refractive index parameter of the medium was systematically adjusted in steps of 0.1 (ranging from 1.7 to 2.1) to analyze the response characteristics of the resonant frequency shift. Figure 10The influence of different refractive indices on the resonance peaks is shown, revealing a regular redshift in both resonance peaks with increasing refractive index. Further analysis indicates a strong linear relationship between the resonance frequency shift and the change in refractive index: according to Figure 11 The fitting results in (a) show that the sensitivity of the electric dipole resonance reaches 281 GHz / RIU; Figure 11 (b) shows that the sensitivity of the quasi-BIC resonance reaches 305 GHz / RIU.

[0034] Finally, Table 2 below presents a comparison of metasurface sensors based on different structures in terms of resonance mechanism, operating frequency, quality factor Q, and sensitivity S, including existing structures such as structure 1 (combination of open ring and metal strip), structure 2 (combination of double open resonant ring and metal short wire), structure 3 (double open ring), and structure 4 (double elliptical ring).

[0035] Table 2 Performance Comparison of the Sensor in this Embodiment with Existing Metasurface Sensors

[0036] As can be seen from Table 2 above, the asymmetric double-opening metal resonant pair metasurface sensor proposed in this embodiment achieves leading levels in both Q value and sensitivity under the premise of realizing the double resonant mode.

[0037] It needs to be explained that electric dipole resonance in Table 2 refers to the displacement of free charges (electrons) within a metasurface structural unit when an electric field is applied, resulting in the generation of an electric dipole moment. Due to the geometric characteristics of the structural unit (e.g., length, width), the charge vibration reaches its maximum when the frequency of the external electric field approaches the unit's natural resonant frequency, thus forming a resonance phenomenon. Quasi-BIC resonance refers to the absence of radiation from the ideal continuous domain bound state (BIC) structure in a metasurface. This means it has no radiation loss (full width at half maximum is 0), and therefore cannot be directly observed on the spectrum. Theoretically, an ideal BIC structure can produce an infinitely high quality factor (Q value). However, since BIC is difficult to observe directly on the spectrum, small perturbations or defects are usually introduced into the structure to determine its frequency position and verify its high Q value. These perturbations produce sharp quasi-BIC peaks (also known as Fano peaks) on the spectrum, allowing for the measurement of the quasi-BIC's frequency and Q value. EIT-like resonance refers to the phenomenon where, under specific conditions, a normally opaque system becomes transparent through strong excitation light, allowing light of certain frequencies to penetrate the material. When a laser irradiates a material, photon energy induces quantized energy level transitions in electrons, resulting in quantum interference effects between different excited states. Through appropriate coherent coupling, when the frequency difference between the control field and the probe field matches the transition frequency of the atomic system, the system becomes transparent within a certain frequency window, forming an electromagnetically induced transparent induction phenomenon. Fano resonance is a type of scattering resonance that produces asymmetric linearity. LC resonance is a localized electromagnetic resonance achieved through artificially designed subwavelength structures. This resonance mode typically involves the geometry and material properties of the structural units, mimicking the behavior of inductors (L) and capacitors (C), thus forming an LC resonance phenomenon similar to that of traditional circuits.

[0038] In summary, this embodiment designs and optimizes an asymmetric double-opening metallic resonant pair metasurface sensor. It innovatively achieves independent control and synergistic optimization of dual-resonance modes through structural asymmetry, successfully exciting both electric dipole resonance and quasi-BIC resonance modes. Through systematic analysis of the electric field distribution and surface current characteristics at the resonance peaks, the physical mechanism of the dual resonance is elucidated: the resonance at frequency f1 originates from electric dipole oscillation, while the resonance at frequency f2 is generated by the quasi-BIC mode induced by symmetry breaking. After structural parameter optimization, the sensor performance is significantly improved: the sensitivity of the electric dipole resonance at f1 reaches 281 GHz / RIU with a quality factor of 385; the sensitivity of the quasi-BIC resonance at f2 reaches 305 GHz / RIU with a quality factor of 297. Therefore, compared with existing technologies, this embodiment simultaneously achieves high sensitivity (S>280 GHz / RIU) and high quality factor (Q>270) in a single sensor, providing new theoretical guidance and technical solutions for the design of high-performance dual-mode metasurface sensors. The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An asymmetric double-opening metal resonant pair metasurface sensor, characterized in that, The device includes a substrate on which a metasurface unit with a preset period length is disposed. The metasurface unit includes two rectangular resonant rings symmetrically arranged based on a preset line of symmetry. The two rectangular resonant rings have a preset center-to-center distance. The rectangular resonant rings have a preset side length and a preset linewidth. The opposite two sides of the rectangular resonant rings are respectively provided with opening gaps of a preset width. The two opening gaps are provided with an asymmetry. The asymmetry is the distance between the central axes corresponding to the two opening gaps. The central axes are perpendicular to the line of symmetry.

2. The asymmetric double-opening metal resonant pair metasurface sensor as described in claim 1, characterized in that, The asymmetry is 2-10 μm.

3. The asymmetric double-opening metal resonant pair metasurface sensor as described in claim 1, characterized in that, The center-to-center distance is 100 μm.

4. The asymmetric double-opening metal resonant pair metasurface sensor as described in claim 1, characterized in that, The preset line width is 7μm.

5. The asymmetric double-opening metal resonant pair metasurface sensor as described in claim 1, characterized in that, The preset width is 4μm and the preset side length is 40μm.

6. The asymmetric double-opening metal resonant pair metasurface sensor as described in claim 1, characterized in that, The preset period length is: 90 μm on the x-axis and 190 μm on the y-axis; wherein the x-axis is parallel to the line of symmetry.

7. An asymmetric double-opening metal resonant pair metasurface sensor as described in any one of claims 1-6, characterized in that, The thickness of the substrate is 35 μm, and the thickness of the metasurface unit is 200 nm.

8. An asymmetric double-opening metal resonant pair metasurface sensor as described in claim 7, characterized in that, The substrate is made of polyimide, and the metasurface unit is made of gold.

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