Type-II structure for multi-dimensionally exciting quasi-BIC resonance and terahertz metamaterial sensor

Abstract

A Terahertz metamaterial sensor and an II-type structure for multi-dimensionally exciting quasi-BIC resonance comprises two first I-type silver strips and two second I-type silver strips which are deposited on a substrate, the two first I-type silver strips are parallel to each other and are symmetrical about a y axis, and the two second I-type silver strips are parallel to each other and are symmetrical about a y axis. The two second I-shaped silver strips are parallel to the x axis and are respectively connected with the two first I-shaped silver strips to form an II-shaped structural unit, and the substrate and the II-shaped structural unit form a microstructure cell of the terahertz metamaterial sensor from bottom to top; wherein the moving distance of one first I-type silver strip from the initial position to the other first I-type silver strip is called as dw1, the moving distance of the other first I-type silver strip from the initial position to the position far away from the adjacent first I-type silver strip is called as dw2, and the moving distance of the dw1 and the moving distance of the dw2 are both 3-5 microns; the terahertz metamaterial sensor comprises n * n microstructure cells which are periodically distributed. According to the utility model, the quasi-BIC can be excited in multiple dimensions, the adjustment depth and the Q factor can be synchronously improved, and the newly generated quasi-BIC resonance can be optimized.

Description

TECHNICAL FIELD

[0001] The utility model relates to a terahertz sensor technology field, specifically a kind of multi-dimension excitation quasi-BIC resonance II type structure and terahertz metamaterial sensor. BACKGROUND

[0002] The concept of bound state in the continuum (BIC) was first proposed by von Neumann and Wigner in quantum mechanics, which corresponds to the frequency in the continuous spectrum and coexists with the radiation wave. Since the BIC mode supports an infinite quality factor, it can still maintain a completely closed state, so the mode cannot be coupled with the radiation wave and does not occur any energy leakage. In subsequent studies, it was found that quasi-BIC mode is a resonant mode with a finite Q factor, which can be excited by breaking the BIC condition by incident light close to the BIC wavelength. The extremely high finite Q factor enhances the light-matter interaction, so the research based on BIC has great application prospects in high-sensitivity sensing, chiral enhancement, fingerprint spectrum detection and other aspects.

[0003] As an artificial periodic structure, the unique electromagnetic properties of metamaterials mainly come from its graphic structure and size. By designing micro-nano structure units to manipulate the propagation of light and the interaction between light and matter, metamaterials can achieve optical performance that traditional materials cannot achieve. The size of these micro-nano structure units is usually much smaller than the wavelength of incident light, so the light wave will regard these structures as a kind of uniform medium, thus exhibiting completely different optical properties from the constituent materials. After the first metamaterial absorber was designed in 2008, metamaterials have received extensive attention and research from researchers. To meet the different performance requirements of different devices, by changing the structural parameters of metamaterials, different modes of resonance can be excited to realize the near-field and far-field modulation of electromagnetic response.

[0004] There are structures that can excite quasi-BICs, which have mirror or rotational symmetry and can suppress the coupling between different modes. In general periodic structures, BICs are usually associated with the center of the first Brillouin zone, and structures with C2 symmetry can prevent the coupling of odd and even modes at the Gamma point, thereby forming BICs. In order to excite BIC states to quasi-BIC states, the symmetry of the original symmetric structure needs to be destroyed, and the coupling between the BIC state and the radiation mode causes leakage, and the BIC state becomes a quasi-BIC state. The existing structures that excite quasi-BICs are structures that excite quasi-BICs by destroying the symmetry of the structure. Since the Q factor and the square of the asymmetry parameter are inversely proportional when the symmetrically protected BIC is excited to a quasi-BIC, the existing structures that excite quasi-BICs by destroying symmetry often change a single parameter in a single dimension to excite quasi-BICs. In the case of small initial resonant radiation levels, it is often difficult to achieve a large degree of step phenomenon, which also limits the newly generated quasi-BIC resonance. In most of the existing research on quasi-BIC modes excited by destroying symmetry, either the Q factor is high but the modulation depth is small, which is not easy to observe, or the modulation depth is sufficient but the Q factor is not high. The existing structures that excite quasi-BICs by destroying symmetry almost cannot improve the Q factor and the modulation depth at the same time, resulting in the need to abandon part of the optical properties in many directions, and the newly generated quasi-BIC resonance is not optimized. Practical new type content

[0005] The utility model aims at providing a kind of multi-dimension excitation quasi-BIC resonance's II type structure and terahertz metamaterial sensor, can multi-dimension excitation quasi-BIC synchronous promotion modulation depth, slow down Q factor drop speed, optimize the newly generated quasi-BIC resonance.

[0006] In order to solve the above technical problems, the utility model adopts the specific scheme of a kind of multi-dimension excitation quasi-BIC resonance's II type structure, including two first I type silver strip and two second I type silver strip deposited on substrate, two first I type silver strip parallelly arranged and respectively located about y axis symmetric positive half axis and negative half axis, two second I type silver strip is parallel to x axis and is connected with the end of two first I type silver strip respectively to form II type structure unit, substrate and the II type structure unit deposited on substrate constitute the microstructure unit cell of terahertz metamaterial sensor from bottom to top;

[0007] The distance that one of the two first I type silver strip moves from initial position towards another first I type silver strip is called dw1, and the distance that another first I type silver strip moves from initial position away from adjacent first I type silver strip is called dw2, the moving distance of dw1 and dw2 is 3-5 μm;

[0008] The length and width of the substrate are 90-95 mu m, and the thickness of the substrate is 25-30 mu m; the length of the first I-shaped silver strip is 60-65 mu m, the width of the first I-shaped silver strip is 3-5 mu m, the length of the second I-shaped silver strip is 40-45 mu m, the width of the second I-shaped silver strip is 6-10 mu m, and the thickness of the first I-shaped silver strip and the second I-shaped silver strip is 0.2-0.5 mu m.

[0009] As another optimization scheme of the II-type structure for multi-dimensionally exciting quasi-BIC resonance, the moving distance of dw1 and dw2 is 4 mu m.

[0010] As another optimization scheme of the II-type structure for multi-dimensionally exciting quasi-BIC resonance, the length and width of the substrate at the microstructure unit cell are 90 mu m, the thickness of the substrate is 25 mu m, and the material of the substrate is polytetrafluoroethylene.

[0011] As another optimization scheme of the II-type structure for multi-dimensionally exciting quasi-BIC resonance, the length of the first I-shaped silver strip is 60 mu m, the width of the first I-shaped silver strip is 3 mu m, and the thickness of the first I-shaped silver strip is 0.3 mu m.

[0012] As another optimization scheme of the II-type structure for multi-dimensionally exciting quasi-BIC resonance, the length of the second I-shaped silver strip is 40 mu m, the width of the second I-shaped silver strip is 6 mu m, and the thickness of the second I-shaped silver strip is 0.3 mu m.

[0013] A terahertz metamaterial sensor for multi-dimensionally exciting quasi-BIC resonance comprises n x n periodic distribution of the microstructure unit cell composed of any one of the II-type structures for multi-dimensionally exciting quasi-BIC resonance.

[0014] Compared with the prior art, the utility model has the advantages of the following beneficial effects:

[0015] In the utility model, the II-type structure unit is composed of two first I-shaped silver strips and two second I-shaped silver strips which are symmetrically arranged on the substrate, the substrate and the II-type structure unit deposited on the substrate form the microstructure unit cell of the terahertz metamaterial sensor from bottom to top, the first I-shaped silver strip on the left side among the two first I-shaped silver strips is moved from the initial position to the right side by a distance, which is called the tuning parameter dw1, and the first I-shaped silver strip on the right side is moved from the initial position to the right side by a distance, which is called the tuning parameter dw2.

[0016] The utility model discloses a change tuning parameter dw1 and dw2 in II shape structure can multidimensional excitation quasi BIC resonance, can obtain better spectral response, can reach 99.99% modulation depth in smaller control range, and the influence degree of leak mode is far greater than intrinsic mode, avoid the frequency band influence that two modes are close to each other bring.In the optimal parameter of tuning parameter dw1 and tuning parameter dw2, through the analysis to the sensing characteristic of the terahertz metamaterial sensor, the highest Q factor can reach 167.142, after adding the thickness 10um of the analyte to be measured, through the change of the refractive index of the analyte to be measured, the minimum value of sensing sensitivity can reach 576GHz / RIU, and the maximum FOM value is 37.571RIU-1, compare the above-mentioned result with the existing terahertz metamaterial sensor can find that Q factor and modulation depth all have very big promotion, along with the increase of resonance intensity, Q factor and modulation depth all have been promoted, and the resonance performance of quasi BIC also can be optimized. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Fig. 1 is a schematic diagram of a terahertz metamaterial sensor, and Fig. 2 is a schematic diagram of a single II type structure unit and corresponding tuning parameters;

[0018] Figure 2 Fig. 3 is a FDTD simulation transmission spectrum diagram of coupled modes under the influence of multiple physical parameters, Fig. 4 is an electric field distribution diagram under Mode1, and Fig. 5 is an electric field distribution diagram under Mode2;

[0019] Figure 3 Fig. 6 is a multi-level sub-scattering power under Mode1, and Fig. 7 is a multi-level sub-scattering power under Mode2;

[0020] Figure 4 Fig. 8 is a response characteristic diagram of the real part and the imaginary part of the impedance matching of the terahertz metamaterial device to the electromagnetic wave with the change of frequency;

[0021] Figure 5 Fig. 9 is a transmission spectrum and the change of modulation depth and Q factor after parameter adjustment of the terahertz metamaterial sensor, Fig. 9 (a) only changes dw1, Fig. 9 (b) only changes dw2, Fig. 9 (c) changes dw1 and dw2 at the same time, Fig. 9 (d) only changes dw1, Fig. 9 (e) only changes dw2, and Fig. 9 (f) changes dw1 and dw2 at the same time;

[0022] Figure 6 Fig. 10 is a terahertz wave transmission spectrum response diagram under different loss tangent values, Fig. 10 (a) is under Mode1, and Fig. 10 (b) is under Mode2;

[0023] Figure 7(a) shows the transmission spectra of several common analytes placed on a metasurface; (b) shows the effect of analyte thickness on the Mode2 sensing performance.

[0024] Figure 8 Transmission spectra of an analyte with a thickness of 10 μm and a refractive index of 1–2 placed on a metasurface are shown in (a) transmission thermal map; the black dashed arrows indicate the frequency change with increasing n; (b) transmission valley resonance frequency shift compared to the change in the refractive index of the analyte; the sensitivity of the metamaterial sensor can reach 576 GHz / RIU.

[0025] Reference numerals: 1. Substrate; 2. First type I silver strip; 3. Second type I silver strip. Detailed Implementation

[0026] like Figure 1 As shown, a type II structure and terahertz metamaterial sensor with multidimensional excitation of quasi-BIC resonance includes two first type I silver strips 2 and two second type I silver strips 3 deposited on a substrate 1. The two first type I silver strips 2 and the two second type I silver strips 3 are both made of silver, and the substrate 1 is made of polytetrafluoroethylene.

[0027] Two first type I silver strips 2 are symmetrically arranged, and two second type I silver strips 3 are arranged in parallel and connected to the ends of the two first type I silver strips 2 respectively to form a type II structural unit. The substrate 1 and the type II structural unit deposited on the substrate 1 constitute the microstructure cell of the terahertz metamaterial sensor from bottom to top.

[0028] like Figure 1 As shown in (a), this terahertz metamaterial sensor consists of n x n periodically distributed type II microstructure cells, periodically deposited on a polytetrafluoroethylene substrate 1. It is primarily used to detect incident terahertz waves and exhibits different frequency shifts depending on the refractive index of the analyte placed on the glass slide. Figure 1 As shown in (b), the structural parameters of the microstructure cells are as follows: the length and width of substrate 1 are both 90 μm, and the thickness of substrate 1 is 25 μm. The length of the first type I silver strip 2 is 60 μm, and the width of the first type I silver strip 2 is 3 μm. The length of the second type I silver strip 3 is 40 μm, and the width of the second type I silver strip 3 is 6 μm.

[0029] The thickness of the two first type I silver strips 2 and the two second type I silver strips 3 is 0.3 μm. The thickness of the silver material is 0.3 μm. Theoretical simulation results show that the thickness of the silver material is 0.3 μm. The interference problem between the metal cavity enclosed by the two first type I silver strips 2 and the two second type I silver strips 3 has almost no impact on the sensing performance of the terahertz metamaterial sensor.

[0030] The leftmost first I-shaped silver strip 2 among the two first I-shaped silver strips 2 is formed by Figure 1 The distance by which the initial position of the left dashed white line in (b) is moved towards the right is referred to as the tuning parameter dw1, and the other rightmost first I-shaped silver strip 2 is formed by Figure 1 The distance by which the initial position of the right dashed white line in (b) is moved towards the right is referred to as the tuning parameter dw2. For the design of dw1 and dw2, it can be understood that the two symmetric first I-shaped silver strips 2 are respectively located on the positive and negative half axes about the y-axis, and the "initial" of the first I-shaped silver strip refers to the position when the single workpiece structure has a symmetry axis parallel to the Y-axis.

[0031] In the simulation process, numerical calculation was performed by using a three-dimensional finite-difference time-domain (FDTD) solving software. Periodic boundary conditions were used in the x and y directions, and a perfect matched layer (PML) absorbing boundary condition was used in the z direction of the free space. By setting the grid size to be smaller than the corresponding minimum structure size, it was ensured that convergent results could be obtained, and the simulation results are shown in the solid line part of (a). Figure 2

[0032] From (a), it can be seen that two obvious transmission valleys appear near the frequencies f = 1.553 THz and f = 2.318 THz, which correspond to Mode 1 and Mode 2, respectively. Figure 2 (b) and (c) respectively show the electric field distribution diagrams under Mode 1 and Mode 2. The electric field distribution diagram under Mode 1 shows that the electric field is mainly concentrated at the end of the leftmost first I-shaped silver strip 2 parallel to the y-axis, and a strong local electric field is formed in the gap region between the two first I-shaped silver strips 2, which indicates that Mode 1 corresponds to a dipole resonance mainly at the end of the first I-shaped silver strip 2. Figure 2 The electric field distribution diagram under Mode 2 shows that the electric field is more significantly enhanced at the two ends of the second I-shaped silver strip 3 parallel to the x-axis and the middle part of the first I-shaped silver strip 2 parallel to the y-axis, indicating that Mode 2 is a higher-order resonance mode, which is due to the destruction of the symmetry of structure C2, the horizontal wave vector of the electromagnetic mode deviates from the Γ point, and a new radiation channel is generated by quasi-BIC excitation. Generally speaking, the radiation energy of the intrinsic resonance state after the interaction of the closed resonance cavity with the radiation continuum is much larger than that of the ordinary vibration mode at the lowest energy state, but when the asymmetry is enhanced to a certain extent, the radiation of the quasi-BIC resonance will degenerate to the level of ordinary resonance.

[0033]

[0034] ​​To explore the mechanism of BIC mode in this study, we calculated the contribution rate of different multipole components of the super surface induced current density in the Cartesian coordinate system, and gave the multipole scattering power of the two modes, respectively, as shown in Figure 3 (a)-(b). From Figure 3 (a)-(b) can be seen that in the resonance frequency range of Mode 1, it is mainly dominated by magnetic dipole (MD) and electric quadrupole (EQ) modes, and the overall contribution rate is very weak, which can reach 0.00212μm 2 .

[0035] And in the resonance frequency range of Mode 2, the multi-level component response is strong, among which the toroidal dipole (Torid) mode is dominant, which is mainly derived from the closed loop formed between the z-direction current generated by the second I-type silver strip 3 parallel to the x-axis and the y-direction current generated by the first I-type silver strip 2 parallel to the y-axis, forming the current flow direction in the x direction, which is manifested as the toroidal dipole. The highest contribution rate in the overall mode can reach several hundred times of the intrinsic mode, with strong light response.

[0036] In addition, the impedance matching theory is used to explain the generation of resonance peak. When the impedance of the incident medium matches the impedance of the metamaterial, the electromagnetic wave can be theoretically completely absorbed, thereby producing a transmission rate of 0. As shown in Figure 4 , the real part Re(Z) and the imaginary part Im(Z) change with the frequency, which shows the response characteristics of the material to the electromagnetic wave. When the frequency reaches the resonance position, it can be found that there is a relatively obvious change, that is, the real part of the impedance tends to 1 and the imaginary part tends to 0, indicating that the impedance of the designed terahertz metamaterial sensor gradually matches the impedance of the free space, so that a very high modulation depth can be obtained.

[0037] The main reason for the formation of the two resonance modes is that Mode 1 is more from the cavity formed by the two first I-type silver strips 2 parallel to the y-axis, and the dipole mode is also from the closed loop formed by the cavity. Mode 2 forms a local mode due to the symmetry breaking between the second I-type silver strip 3 parallel to the x-axis and the first I-type silver strip 2 parallel to the y-axis.

[0038] As shown in Figure 5 (a), when only dw1 is increased, the left first I-type silver strip 2 moves to the right, the cavity area decreases, and the length of the contact between the left first I-type silver strips 2 increases. This will produce a similar modal distribution, Mode 1 is constantly blue-shifted in the process, and the line width becomes smaller. Mode 2 shows the general form of quasi-BIC excitation, the spatial symmetry is broken, the BIC jumps to the supercavity mode, the super-radiation mode is converted to the sub-radiation mode, the Q factor changes from infinite to finite, the line width and the inclination angle increase constantly, the modulation depth rises, and the leakage mode is completely excited.

[0039] Modulation depth and Q-factor change as Figure 5 (d) shows that when dw1 is within 0-3 μm, the modulation depth increases rapidly, while the Q-factor decreases rapidly. When dw1 = 5 μm, the modulation depth reaches 99.99%, and the Q-factor reaches 112.3. The overall change trend in the latter half is relatively flat.

[0040] As shown in Figure 5 (b), when only dw2 is increased, the cavity area increases in the process of increasing, and Mode1 moves to a lower frequency. As shown in Figure 5 (e), the length of the contact between the first I-type silver strips 2 on the left side does not change, even if the symmetry is destroyed, a strong local area of the light field is not formed, and therefore the transmission phenomenon cannot occur.

[0041] Further analysis and verification are made for the generation and change process of the new resonant mode due to the destruction of symmetry. As follows, the electromagnetic property changes by simultaneously changing multiple parameters, i.e., simultaneously increasing dw1 and dw2. The results are shown in Figure 5 (c). In this process, the cavity size between the two first I-type silver strips 2 is first kept unchanged, that is, dw1 and dw2 are kept at the same growth rate. The results show that the resonance intensity and phase of Mode1 are basically unchanged, and the resonance response of Mode2 has more obvious changes compared with the case of changing dw1 only. This indicates that within a limited range, the high-order resonant mode can be more easily excited.

[0042] At the same time, it can be seen from Figure 5 (f) that the nonlinearity of the degree of asymmetry is increasing as dw1 and dw2 increase. When dw1 = dw2 = 4 μm, the modulation depth reaches 99.99%, and the Q-factor reaches 167.142. Compared with the spectral response in the single dimension, the modulation depth increases faster and the Q-factor decreases at a slower speed, the amplitude modulation is more obvious, and it is easier to excite the quasi-BIC.

[0043] Finally, the designed terahertz metamaterial sensor is used for sensing application test. The specific influence of the loss tangent value on the absorption characteristics can optimize the response range and sensitivity of the sensor, and improve the specificity and accuracy of detection. Therefore, first, the spectral response under different loss tangent values (tanδ) when the refractive index of the analyte to be tested is 1 is calculated, and the results are shown in Figure 6 It can be seen that when tanδ increases from 0 to 0.1, the transmission spectral line width of both Mode1 and Mode2 modes increases, in which the modulation depth of Mode1 mode decreases from 98.6% to 86.5%, and the modulation depth of Mode2 mode decreases from 98.6% to 45.4%.

[0044] However, the position of the resonance valley remains essentially unchanged in either mode. This is because the loss tangent value is a measure of the degree of dissipation of electromagnetic wave energy by the material, which characterizes the dielectric loss of the material, i.e. the efficiency of the energy consumption when the internal charges of the material vibrate under the action of the electromagnetic field. When the tanδ value increases, it means that the electromagnetic loss of the material increases, and the increase in total loss leads to an increase in the linewidth (Q factor decreases). The material loss also leads to a decrease in the degree of radiation, which in turn leads to a significant decrease in the transmission amplitude. By comparing the two modes of Mode1 and Mode2, it is found that the influence of tanδ on Mode2 is much greater than that of Mode1. Therefore, as a sensor, the change of the analyte tanδ can be effectively distinguished according to the change degree of the transmission spectrum.

[0045] Secondly, we simulated the performance indicators of the designed terahertz metamaterial sensor. It is assumed that the refractive index of the analyte to be measured is between 1.0 and 2.0, such as the refractive index of common air is 1, the refractive index of ovalbumin is about 1.15, the refractive index of ammonia is 1.22, the refractive index of ethanol is 1.36, and the refractive index of trinitrotoluene (TNT) is 1.43, as shown in Figure 7 (a). In the present application, the influence of the thickness h of the analyte on the sensing performance is also simulated, and the results show that the thickness of the analyte has almost no effect on the sensing performance when the thickness reaches 10 μm, as shown in Figure 7 (b). Finally, by placing the analyte to be measured with a thickness of 10 μm, the sensitivity of the proposed sensor residing on the PTFE substrate is studied by changing its refractive index. The sensitivity of the refractive index sensor is defined as S = Δf / Δn, where Δf represents the frequency shift amount of the resonance peak corresponding to the change of the refractive index of the analyte to be measured, and Δn represents the change amount of the refractive index of the analyte to be measured.

[0046] Figure 8 (a) shows the resonance frequency shift results of the analyte to be measured when dw1 = dw2 = 4 μm. When the refractive index of the analyte changes from n = 1 to n = 2, a relatively large resonance frequency shift is observed, and the resonance frequency decreases with the increase of the refractive index, which is a typical transmission resonance phenomenon. We also observe that the frequency shift degree of Mode1 is less than that of Mode2. As shown in Figure 8(b) As shown, by linear fitting, we calculate the function relationship between the resonance frequency f and Δn as y = 2.314-0.576x, and the sensor sensitivity based on quasi-BIC in multiple dimensions is 576 GHz / RIU. Meanwhile, according to FOM = S / FWHM, wherein FWHM represents the full width at half maximum (FWHM) of the resonance peak. Finally, the maximum FOM value of the sensor can reach 37.571, so the terahertz metamaterial sensor in the application performs excellently in sensing the refractive change of the environment and has good sensing characteristics.

Claims

1. A type-II structure for multi-dimensional excitation of quasi-BIC resonances, characterized in that: The microstructure unit cell of the terahertz metamaterial sensor is formed by a substrate (1) and a II-type structure unit deposited on the substrate (1) from bottom to top, the II-type structure unit is composed of two first I-type silver strips (2) and two second I-type silver strips (3) deposited on the substrate (1), the two first I-type silver strips (2) are arranged in parallel and respectively located on the positive half-axis and the negative half-axis with respect to the y-axis, the two second I-type silver strips (3) are arranged in parallel to the x-axis and respectively connected with the end portions of the two first I-type silver strips (2) to form the II-type structure unit. The distance by which one of the two first I-type silver strips (2) moves from the initial position towards the other first I-type silver strip (2) is referred to as dw1, and the distance by which the other first I-type silver strip (2) moves from the initial position away from the adjacent first I-type silver strip (2) is referred to as dw2, the moving distances of dw1 and dw2 are both 3-5 μm. The length and the width of the substrate (1) are both 90-95 μm, the thickness of the substrate (1) is 25-30 μm, the length of the first I-type silver strip (2) is 60-65 μm, the width of the first I-type silver strip (2) is 3-5 μm, the length of the second I-type silver strip (3) is 40-45 μm, the width of the second I-type silver strip (3) is 6-10 μm, and the thickness of the first I-type silver strip (2) and the second I-type silver strip (3) is 0.2-0.5 μm.

2. The II-type structure of claim 1, wherein the moving distances of dw1 and dw2 are both 4 μm. The length and the width of the substrate (1) at the microstructure unit cell are both 90 μm, the thickness of the substrate (1) is 25 μm, and the material of the substrate (1) is polytetrafluoroethylene.

3. The structure of claim 1, wherein: The length of the first I-type silver strip (2) is 60 μm, the width of the first I-type silver strip (2) is 3 μm, and the thickness of the first I-type silver strip (2) is 0.3 μm.

4. The structure of claim 1, wherein: The length of the second I-type silver strip (3) is 40 μm, the width of the second I-type silver strip (3) is 6 μm, and the thickness of the second I-type silver strip (3) is 0.3 μm.

5. The structure of claim 1, wherein: The microstructure unit cell is composed of n×n periodic distribution of the II-type structure of any one of claims 1-5.

6. A multi-dimensional excitation quasi-BIC resonant terahertz metamaterial sensor, characterized in that: ​

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