All-dielectric metasurface double QBIC structure and application

Abstract

The application provides a full dielectric metasurface double QBIC structure, and the full dielectric metasurface double QBIC structure comprises a substrate and a silicon nanodisk from bottom to top in sequence; wherein, an eccentric hole is arranged on the silicon nanodisk. The full dielectric metasurface composed of a periodic array of silicon nanodisks is adopted, the asymmetry is broken (the eccentric hole is introduced), the transmission spectrum of the metasurface shows Fano resonance double peaks, the Q factors of the two quasi-BICs are inversely proportional to the asymmetry parameter, it is proved that the two modes are QBIC, and the Q factor can be adjusted by 3 orders of magnitude through the regulation of the asymmetry parameter.

Description

Technical Field

[0001] This invention belongs to the field of all-dielectric metasurface structure technology, and specifically relates to an all-dielectric metasurface dual QBIC structure and its application. Background Technology

[0002] Metasurfaces are two-dimensional metamaterials composed of numerous subwavelength arrays, possessing excellent properties, small size, ease of fabrication, and ease of integration. A special optical phenomenon exists in metasurface systems: bound states in the continuous (BIC). This phenomenon manifests as a radiation continuous spectrum with eigenfrequency above the optical cone, yet without radiation leakage; it is a unique, completely bound mode exhibiting significant electromagnetic field localization. The concept of BIC originated in quantum mechanics, introduced in 1929 by von Neumann and Wegner based on the Schrödinger equation, and has since been extensively studied in wave physics. In 2008, the concept of BIC was first introduced into the field of optics. In 2011, Plotnik et al. experimentally confirmed the existence of optical BICs in two-dimensional waveguide array structures. Subsequently, it has been confirmed in various optical structures such as optical waveguide arrays, nanophotonic crystal thin plates, and metasurfaces, and high-quality factor resonance has been achieved through BICs. An ideal BIC (Bright Induction Channel) is a resonant mode with zero bandwidth due to complete decoupling from free-space radiation. Theoretically, it has an infinitely large quality factor (Q factor) and a radiation lifetime approaching infinity. Spectally, this manifests as the disappearance of the Fano resonance linewidth, with energy completely localized in a very small region. However, this dark mode cannot be observed; it only becomes practically meaningful when coupled with surrounding spatial radiation to transform into a leakage mode with an ultra-narrow linewidth. Typically, asymmetry breaking or parameter perturbations are introduced to couple it with an external channel, transforming it into a quasi-BIC mode. A quasi-BIC is a radiative leakage mode near the ideal BIC. This resonant mode is accompanied by a finite but very large Q factor and a strong local field enhancement effect, which can greatly enhance the interaction between light and matter, exhibiting a sharp Fano linewidth in the transmission spectrum. Furthermore, BICs supported by metasurfaces are relatively easier to control. Taking a symmetry-protected BIC as an example, the intensity of the quasi-BIC resonance can be precisely controlled simply by introducing and controlling symmetry breaking on the metasurface.

[0003] The high Q-factor and easy tunability of quasi-BIC (biologically bipolar integrated circuit) have attracted considerable attention and have been applied in many fields, such as filters, lasers, nonlinear devices, and sensors. Quasi-BIC metasurfaces have wide applications in sensing, particularly in the currently popular field of bio-optical sensing. Metasurfaces based on the quasi-BIC phenomenon possess a large Q-factor, making them highly sensitive to changes in the surrounding medium. Specifically, the position of the resonance peak in the spectrum changes with minute variations in the surrounding medium, and the wavelength of the resonance peak changes linearly with the refractive index of the surrounding medium. This provides the conditions for realizing high-sensitivity optical sensors. Metallic metasurfaces have a lower Q-factor due to their large ohmic loss in the near-infrared band of biosensing, while all-dielectric metasurfaces, with their easy tunability and low ohmic loss, achieve even higher FOM (focal distance) values ​​and sensitivity. Optical biosensors based on quasi-BIC all-dielectric metasurfaces also exhibit significant advantages in complex environments, such as strong electric fields, strong electromagnetic waves, or extreme temperature conditions, due to their less invasiveness. Therefore, all-dielectric metasurfaces have considerable application potential in the field of biosensing.

[0004] Currently, many metasurface-based sensors have been proposed. In 2021, Li et al. designed a metasurface consisting of a nanocube array with two etched square holes. This metasurface supports multiple Fano resonances, achieving a refractive index sensitivity of 287.5 nm / RIU and a figure of merit of 389 RIU. -1 In 2022, Liu et al. proposed a metasurface composed of an array of aluminum unit cells deposited on a silicon substrate. The unit cells of this array consisted of two isosceles right triangles connected by a rectangle. The sensor operated in the terahertz band, achieving a refractive index sensing sensitivity of 11.17 GHz / RIU. In 2023, Li et al. constructed a metasurface array with a unit cell structure composed of two identical GaP cuboids, achieving refractive index sensing sensitivities of 135 nm / RIU and 45 nm / RIU under x-polarization and y-polarization, respectively. However, current research mostly focuses on sensing a single parameter based on a single BIC. Research on multi-parameter sensing based on multiple BICs is relatively limited, especially for dual-parameter sensing of refractive index and temperature. The refractive index of many media is affected by temperature, so the temperature effect needs to be considered when accurately measuring the refractive index. Simultaneously measuring both temperature and refractive index is crucial for many sensing applications.

[0005] Several methods exist for simultaneously measuring temperature and refractive index, such as silicon bottle resonator sensors, fiber optic sensors, and plasma waveguide sensors. Silicon bottle resonator sensors exhibit relatively low sensitivity for both refractive index and temperature. Fiber optic sensors suffer from complex manufacturing processes and high costs. Plasma waveguide sensors inevitably experience broadening of the resonant linewidth due to ohmic losses in the metal, leading to a decrease in the Q-factor and consequently affecting sensing accuracy and figure of merit. Sensors constructed from all-dielectric metasurfaces exhibit low loss, a large Q-factor, and are simple to manufacture with lower processing costs, making them suitable for mass production and possessing significant application potential in biosensing. Currently, all-dielectric metasurfaces are primarily used for basic sensing of refractive index and temperature changes, with limited research in biosensing, and even less research on simultaneously sensing the refractive index and temperature of biological components, such as the simultaneous sensing of refractive index and temperature parameters of cells and biological proteins. To achieve simultaneous sensing of both temperature and refractive index parameters, the spectrum needs two or more resonant peaks with a linear response to changes in temperature and refractive index.

[0006] Chinese invention patent CN117590503A discloses an all-dielectric metasurface structure, a refractive index sensor, and its biosensing application. From bottom to top, it includes a SiO2 substrate and a Si layer. The Si layer has two cylindrical pores. However, this patent has the following drawback: the refractive index of the biological component is affected by the ambient temperature. To accurately sense the refractive index of the biological component, it is necessary to sense both the ambient temperature and the refractive index of the biological component simultaneously.

[0007] Therefore, it is essential to develop a more sensitive and efficient method for detecting biological proteins. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention develops an all-dielectric metasurface composed of a periodic array of eccentrically concave circular disks and proposes a method for simultaneously sensing the refractive index of biological components and ambient temperature. Typically, an asymmetrically broken eccentric circular aperture is introduced, coupling it with the surrounding space to form a quasi-BIC mode. By adjusting the radius of the eccentric circular aperture, the Q factor and resonance peak linewidth can be flexibly controlled, thereby adjusting the sensing performance. Calculations show that the metasurface exhibits two Fano resonance line shapes in the transmission spectrum. The Q factors of both quasi-BIC modes are inversely proportional to the asymmetry parameter, further confirming that both modes are quasi-BIC resonances. Finally, a sensitivity sensing matrix is ​​constructed. By measuring the wavelength position changes of the two quasi-BIC resonance peaks, simultaneous sensing of background refractive index and ambient temperature can be achieved, with sensing errors not exceeding ±5%. This enables high-precision sensing and measurement of the refractive index of biological proteins and ambient temperature, providing more reliable detection results. This superior biosensing performance based on dual QBIC (quasi-continuous domain bound states) is expected to play an important role in the future development of bio-optical sensing, providing a new approach for high-sensitivity and high-precision bio-optical detection.

[0009] The purpose of this invention is to provide an all-dielectric metasurface dual QBIC structure, wherein the all-dielectric metasurface dual QBIC structure comprises, from bottom to top, a substrate and a silicon nanodisk; The silicon nanodisk is provided with an eccentric circular hole; The distance between the center of the silicon nanodisk and the center of the eccentric circular hole is 130-150 nm.

[0010] Furthermore, the radius R of the silicon nanodisk is 200-400 nm.

[0011] Furthermore, the height H of the silicon nanodisk is 50-200 nm.

[0012] Furthermore, the radius r of the eccentric circular hole is 20-80 nm.

[0013] Furthermore, in the all-dielectric metasurface double QBIC structure, the quality factor Q value is greater than or equal to 100.

[0014] Furthermore, the operating wavelength of the all-dielectric metasurface dual QBIC structure is 1050-1450 nm.

[0015] The present invention also provides a dual-parameter biosensor based on a fully dielectric metasurface dual QBIC, comprising an array of the fully dielectric metasurface dual QBIC structure.

[0016] Furthermore, in the array, the period of the all-dielectric metasurface dual QBIC structure is Px=Py=700-1000nm.

[0017] Furthermore, the background refractive index n of the dual-parameter biosensor based on all-dielectric metasurface dual QBIC B It is 1.0-1.5.

[0018] The present invention also provides the application of the dual-parameter biosensor based on all-dielectric metasurface dual QBIC in the detection of refractive index of biological components and detection of ambient temperature.

[0019] The beneficial effects of this invention are as follows: This invention employs an all-dielectric metasurface composed of a periodic array of silicon nanodisks. By introducing asymmetry breaking (eccentric circular holes), the transmission spectrum of the metasurface exhibits a Fano resonance double peak. The Q-factors of these two quasi-BICs (labeled QBIC1 and QBIC2, respectively) are both inversely proportional to the asymmetry parameter, confirming that both modes are QBICs. Furthermore, the Q-factors can be adjusted by three orders of magnitude through the manipulation of the asymmetry parameter. Compared to existing technologies, this invention enables high-precision sensing and measurement of the refractive index of biological components and ambient temperature, providing more reliable detection results. This superior biosensing performance based on dual QBICs is expected to play an important role in the future development of bio-optical sensing, providing a new approach for high-sensitivity and high-precision bio-optical detection.

[0020] Furthermore, by constructing a sensitivity sensing matrix and measuring the wavelength changes of the resonance peaks of two quasi-BICs, simultaneous detection of the refractive index of biological components and ambient temperature can be achieved with relative errors not exceeding ±5%, enabling high-precision sensing of both refractive index and ambient temperature. This dual-resonance mode collaborative detection mechanism provides a new approach for developing high-precision multi-parameter optical biosensors and has significant application potential in the fields of biomolecular detection and environmental monitoring. Attached Figure Description

[0021] Figure 1 Schematic diagrams of the all-dielectric metasurface structure from different perspectives; in: Figure 1 (a) is a schematic diagram of the silicon nanodisk structure of the present invention; Figure 1 (b) is a front view of the all-dielectric metasurface structure of the present invention; Figure 1 (c) is a top view of the all-dielectric metasurface structure of the present invention.

[0022] Figure 2 This is a test diagram of the all-dielectric metasurface structure of the present invention; in: Figure 2 (a) is a schematic diagram of the silicon nanodisk periodic array of the present invention; Figure 2(b) is a diagram of the photonic band structure of Example 1.

[0023] Figure 3 This is the transmission spectrum of the all-dielectric metasurface structure of the present invention; in: Figure 3 (a) Transmission spectra of Example 1 and Comparative Example 1; Figure 3 (b) Transmission spectra showing the effect of different eccentric aperture radii r on QBIC; Figure 3 (c) shows the relationship between the transmission spectrum and the radius of the eccentric circular aperture. Figure 3 (d) shows the functional relationship between the Q factor and the asymmetry parameter α for different eccentric circular hole radii QBIC1 and QBIC2.

[0024] Figure 4 The near-field distribution of the electric field in the xy plane for QBIC1 and QBIC2; in: Figure 4 (a) is the near-field distribution of the electric field in the xy plane corresponding to QBIC1 with r=80nm; Figure 4 (b) shows the near-field distribution of the electric field in the xy plane corresponding to QBIC2 with r=80nm.

[0025] Figure 5 The test results for QBIC1 and QBIC2 at different refractive indices of biological components are shown. in: Figure 5 (a) Transmission spectra of QBIC1 at different biological refractive indices; Figure 5 (b) Transmission spectra of QBIC2 at different biological refractive indices; Figure 5 (c) QBIC1 resonance wavelength as a function of biological component refractive index n B Linear fitting; Figure 5 (d) QBIC2 resonance wavelength as a function of biological component refractive index n B Linear fitting.

[0026] Figure 6 Test results for QBIC1 and QBIC2 at different temperatures; in: Figure 6 (a) Transmission spectra of the all-dielectric metasurface of silicon nanodisk at different temperatures in QBIC1; Figure 6 (b) Transmission spectra of the all-dielectric metasurface of QBIC2 silicon nanodisk at different temperatures; Figure 6 (c) shows the linear fit of the QBIC1 resonance wavelength with temperature; Figure 6 (d) is the linear fit of the QBIC2 resonance wavelength with temperature.

[0027] In the figure: 1. Substrate; 2. Silicon nanodisk; 3. Eccentric circular hole. Detailed Implementation

[0028] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided, but the present invention is not limited thereto.

[0029] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0030] Example 1 A fully dielectric metasurface dual QBIC structure, the structure of which is as follows: Figure 1 As shown in (a)-(c), the all-dielectric metasurface dual QBIC structure includes, from bottom to top, a substrate 1 and a silicon nanodisk 2; The silicon nano disk 2 is provided with an eccentric circular hole 3; The substrate is a glass substrate 1 with a thickness of 1000 nm, and the silicon nanodisks 2 have a radius R of 300 nm, a height H of 100 nm, and a periodic dimension P. x =P y =700nm, the distance between the center of the silicon nano disk 2 and the center of the eccentric circular hole 3 is 150nm, and the radius r of the eccentric circular hole is 80nm. The preparation method of the above-mentioned all-dielectric metasurface double QBIC structure is as follows: First, a uniform silicon thin film (100 nm in height) is grown on a SiO2 substrate using low-pressure physical vapor deposition. Then, a photoresist layer (ZEP520, Zeon Corporation) is spin-coated onto the silicon film surface, and cured on a hot plate to form a stable mask. Nanoscale patterning is then performed using electron beam lithography, followed by inductively coupled plasma dry etching to form silicon nanodisks 2 and eccentric circular holes 3. Finally, residual photoresist is stripped with an organic solvent, and surface organic contaminants are removed using oxygen plasma cleaning. This fabrication method achieves highly efficient fabrication of metasurface structures by optimizing the photolithography-etching synergistic process.

[0031] Example 2 A fully dielectric metasurface dual QBIC structure is provided. Compared with Example 1, the radius r of the eccentric circular hole in the structure is 30 nm, and the rest of the structure is the same as that of Example 1.

[0032] Comparative Example 1 A dielectric metasurface structure, compared with Example 1, has the eccentric circular hole removed from the structure, while the rest of the structure is the same as Example 1.

[0033] Test Example 1 To overcome in-plane asymmetry, a transition from symmetric-protected BIC to QBIC was achieved. The asymmetry of the structure was modulated by changing the radius *r* of the eccentric circular aperture in Example 1, thus controlling the QBIC resonance. The system's light source was set to a near-infrared plane wave incident along the -z axis, with a wavelength range of 1050-1450 nm. The electric and magnetic fields were polarized along the y and x axes, respectively, with periodic boundary conditions in the x and y directions and a perfectly matched layer in the z direction. In studying the QBIC of this all-dielectric metasurface, the refractive indices of silicon and glass were set to 3.52 and 1.4, respectively, the background refractive index was set to 1, and the temperature was set to 300 K.

[0034] Silicon nanodisk periodic arrays, such as Figure 2 As shown in (a), by using dipole clouds to excite all possible resonance modes supported by this all-dielectric metasurface, and searching for BICs, the photonic band structure is obtained as follows. Figure 2 As shown in (b), the modes above the photonic band structure ray are typically radiative, acting as a continuum coupled to extended modes. They can even exist at the Γ point above the band structure ray due to symmetry mismatch between the mode distribution of some bound states and the external propagating modes. At the Γ point, when the operating frequency is below the diffraction limit, the only radiative state is a plane wave in the normal direction, where the electromagnetic field is odd under 180° rotation around the z-axis (i.e., C2 symmetry). Therefore, any even modes at the Γ point are BICs due to the zero overlap between their mode distribution and the outgoing wave. Two possible BICs for this metasurface are circled in red in the figure. The electromagnetic field vectors of these two BIC modes are odd under C2 symmetry, characteristic of SP-BICs, and are labeled BIC1 and BIC2. Due to the symmetry mismatch, the resonant modes are completely confined and no longer coupled to other channels in free space; the energy is completely localized in a very small region with an infinitely large Q factor. These two BICs are located in the near-infrared II frequency range.

[0035] Test Example 2 By introducing an eccentric circular hole to break the in-plane symmetry, the BIC is coupled with the radiation modes in the surrounding space. The radiation channel will open and couple with the radiation channel, causing the resonance state to transform from BIC to QBIC, which has a finite but huge Q factor.

[0036] We performed transmission spectroscopy tests on the structures of Example 1 and Comparative Example 1. Figure 3 (a) shows the transmission spectra at r=0 and r=80nm. When r=0 (Comparative Example 1), the transmission linewidth is zero, the resonance peak disappears, the energy is completely confined, and the Q factor is theoretically infinite; when r=80nm (Example 1), the transmission spectrum exhibits a sharp asymmetric Fano resonance line and a narrow depression at λ=1089.17nm and λ=1334.48nm, respectively.

[0037] The radiation rate and transmission linewidth can be adjusted by tuning the asymmetric parameter, namely the radius of the eccentric circular aperture, which is controlled within the range of 20-80 nm in Example 1. Figure 3 (b)-(d) represent the control of the eccentric circular hole radius r on the QBIC. Figure 3 (b) Transmission spectra with different radii were calculated. As shown in the figure, with the increase of the radius r of the eccentric hole, the resonance wavelength position exhibits a blue shift, and the linewidth of the QBIC transmission spectrum resonance gradually increases. This is because with the increase of the radius of the eccentric hole, the effective refractive index of the silicon nanodisk all-dielectric metasurface decreases, resulting in a blue shift of the resonance wavelength position. Figure 3 (c) shows the relationship between the transmission spectrum and the radius of the eccentric circular aperture. When r increases, the transmission tilt angle exhibits a blue shift and broadening.

[0038] According to the fitting formula, Q = ω0 / γ can be calculated, where ω0 is the resonant frequency and γ is the resonant linewidth. Figure 3 (d) shows the functional relationship between the Q factor and the asymmetry parameter α for different eccentric hole radii QBIC1 and QBIC2. The asymmetry parameter α is defined as: (1) The areas of the eccentric circular aperture and the disk are S1 and S0, respectively. As shown in the figure, the Q factors of both QBICs have a significant inverse quadratic relationship with α, and are controlled by the same asymmetry factor, namely the radius r of the eccentric circular aperture. With the change of the radius r of the eccentric circular aperture, the range of the Q factor of the two QBIC resonances exceeds three orders of magnitude, which can largely control the coupling efficiency and the Q factor. Figure 4 (a) and (b) show the near-field distribution of the electric field in the xy plane corresponding to r=80nm. It can be seen that the electric field is significantly enhanced at the eccentric circular aperture, indicating that the incident light along the -z direction is trapped in the metasurface by the magnetic dipole, which significantly enhances the local light-matter interaction and has a huge Q factor. Such a large Q factor provides a promising application prospect for realizing high-resolution optical biosensors.

[0039] Test Example 3 The introduction of symmetry breaking in the BIC (Bipolar Interchange) resonance results in a very narrow linewidth QBIC resonance, leading to a large Q factor, which is beneficial for improving sensor performance. Sensitivity (S) and figure of merit (FOM) are two important indicators for evaluating sensor performance. For refractive index sensing, sensitivity is defined as: (2) Where Δ n B Let Δλ be the change in background refractive index, and Δλ be the change in the position of the resonant wavelength. The figure of merit (FOM) is: (3) Where FWHM is the full width at half maximum (FWHM) of the transmission spectrum resonance peak. For temperature sensing, the sensitivity is defined as: (4) Where Δ T This represents the change in ambient temperature. Spectral contrast is defined as: (5) Where T p T d These represent the maximum and minimum transmittance values ​​of the resonance peak, respectively.

[0040] Typically, the resonance peak wavelength of an all-dielectric metasurface exhibits a redshift in the transmission spectrum with increasing background refractive index. The refractive index sensing performance of the all-dielectric metasurface designed in this paper as a biosensor is discussed below. Many biological components have refractive indices in the range of 1.0–1.5, such as physiological saline (NS, RI=1.33), white blood cells (WBC, RI=1.36), red blood cells (RBC, RI=1.40), and proteins, RNA, and DNA (RI=1.46). Therefore, the background refractive index… n B The refractive index was varied from 1.0 to 1.48 to test the effect of different biological components' refractive index on the QBIC resonance peak, with the ambient temperature set to T=300K. Higher spectral contrast makes the signal easier to identify and detect. Regarding the selection of the eccentric aperture radius, a smaller radius r results in a larger Q factor, a narrower resonance linewidth, and a higher figure of merit. However, as the eccentric aperture radius r decreases, the spectral contrast of the resonance peak decreases. Therefore, a too-small eccentric aperture radius r is detrimental to sensor detection. This paper selects an eccentric aperture radius r=30nm (Example 2) to study the refractive index sensing and temperature sensing performance of this biosensor.

[0041] Figure 5 (a) and Figure 5 (b) shows the transmission spectra of QBIC1 and QBIC2 at different refractive indices of biological components. Figure 5It is evident that a redshift occurs at the resonant wavelength position with increasing refractive index. When the background refractive index increases, the effective refractive index of the silicon nanodisk all-dielectric metasurface structural unit increases, resulting in a redshift at the resonant wavelength position. The resonant wavelength positions of QBIC1 and QBIC2 change with the refractive index of the biological components. n B The relationship between the changes and their linear fitting, such as Figure 5 (c) and Figure 5 As shown in (d), the wavelengths of the two resonance peaks of QBIC1 and QBIC2 are related to the background refractive index. n B The refractive index exhibits a linear relationship, which can be used to sense the refractive index. Through linear fitting, the refractive index sensing sensitivities (denoted as S1 and S2) of QBIC1 and QBIC2 are S1 = 267.96 nm / RIU and S2 = 82.74 nm / RIU, respectively, and their figure of merit (denoted as FOM1 and FOM2) is FOM1 = 4114.86 RIU. -1 and FOM2=663.90RIU -1 .

[0042] Test Example 4 The temperature sensing performance of the silicon nanodisk all-dielectric metasurface biosensor is investigated below. The structure from Example 2 is used, and the ambient temperature is set to change from 0°C to 100°C, with a background refractive index of... n B Set to 1. This paper uses silicon's thermo-optic coefficient κ = 1.84 × 10⁻⁶. -4 The coefficient / K is used for calculation, which represents the gradient relationship between the material's refractive index and temperature, i.e., κ=(n-n0) / (T-T0), where the refractive index is at T0=300K. n O=3.52, the thermo-optical coefficient of glass is much smaller than that of silicon and can be ignored. In the calculation, this linear relationship is used to establish the coupling relationship between the temperature field and the refractive index of the silicon nanodisk. Figure 6 Figures (a) and (b) show the transmission spectra of the silicon nanodisk biosensor at different temperatures. As can be seen from the figures, the positions of both the QBIC1 and QBIC2 resonance peaks redshift with increasing temperature. The relationship between the resonance wavelengths of QBIC1 and QBIC2 and temperature, and their linear fitting, are shown below. Figure 6 (c) and Figure 6 As shown in (d), the wavelengths of the two resonance peaks have a linear relationship with temperature. Through linear fitting calculation, the temperature sensing sensitivities of QBIC1 and QBIC2 (denoted as ST1 and ST2, respectively) reach 26.50 pm / ℃ and 61.50 pm / ℃. When both ambient temperature and background refractive index change, by utilizing the different linear responses of two QBIC resonant wavelengths to the refractive index and temperature of biological components, cross-interference-free dual-parameter biosensing of refractive index and temperature can be achieved. The resonant wavelength shift between the two QBICs can be expressed as: (6) Where Δλ1 represents the change in the resonant wavelength of QBIC1, Δλ2 represents the change in the resonant wavelength of QBIC2, and Δ n B Δ represents the change in refractive index of biological components. T This is expressed as the change in ambient temperature. A is defined as the sensing sensitivity matrix: (7) Where S1 and S2 are the refractive index sensing sensitivities of QBIC1 and QBIC2, respectively, and ST1 and ST2 are the temperature sensing sensitivities of QBIC1 and QBIC2, respectively. According to formula (8), the changes in the refractive index of biological components and ambient temperature are expressed as follows: (8) The two-parameter biosensing model established according to formula (8) can be used to calculate the refractive index change Δλ of the biological component to be measured by detecting the offsets of two QBIC resonant wavelengths Δλ1 and Δλ2. n B With the change in ambient temperature Δ T Because the resonant wavelengths of QBIC1 and QBIC2 exhibit significantly different response characteristics to refractive index and temperature (i.e., different sensitivity responses), the spectral responses of these two resonant modes satisfy the requirement of linear independence. Therefore, an all-dielectric metasurface biosensor based on two QBICs can simultaneously sense both the refractive index of biological components and ambient temperature.

[0043] The accuracy of the two-parameter sensing model based on the resonance of two QBICs is described below. The two-parameter sensing model is calculated by using the resonant wavelength changes of QBIC1 and QBIC2, and the corresponding changes in the refractive index of biological components and the changes in ambient temperature are obtained by formula (8). The accuracy of the two-parameter sensing model can be obtained by comparing it with the set values.

[0044] Table 1 shows the calculation results and relative errors of the dual-parameter sensing of biological component refractive index and ambient temperature. The background refractive index of the designed structure in its initial state is also shown. n B Set to 1, ambient temperature T Set to 293K, Δ n Bset and Δ T setΔλ1 and Δλ2 represent the changes in the refractive index of the biological components and the ambient temperature relative to the initial values ​​set in the calculation. Δλ1 and Δλ2 respectively represent the changes in the resonant wavelengths of QBIC1 and QBIC2 under these set parameters. n Bcal and Δ T cal This represents the change in refractive index of the biological components and the change in ambient temperature calculated according to formula (9). δ n and δ T These are the relative errors of the refractive index of the biological components and the sensing of ambient temperature, respectively. δ n =(Δ n Bcal -Δ n Bset ) / Δ n Bset and δ T =(Δ T cal -Δ T set ) / Δ T set As shown in Table 1, δ n and δ T The values ​​were all within ±5%, indicating that the two-parameter decoupled detection method based on two QBICs has achieved a high level of sensitivity and accuracy.

[0045] Table 1. Calculation results and relative errors of the dual-parameter sensing of background refractive index and ambient temperature in Example 2. In summary, this invention designs an all-dielectric metasurface composed of a periodic array of silicon disks. By introducing asymmetry breaking (eccentric circular aperture), the transmission spectrum of the metasurface exhibits a Fano resonance double peak. The Q-factors of these two quasi-BIC modes (labeled QBIC1 and QBIC2, respectively) are both inversely proportional to the asymmetry parameter, confirming that both modes are QBIC. Furthermore, the Q-factor can be adjusted by three orders of magnitude through the control of the asymmetry parameter. By analyzing the linear response characteristics between the wavelength of the double resonance peaks and the refractive index of the medium and the ambient temperature, the refractive index sensing sensitivity and figure of merit of the silicon disk all-dielectric metasurface can reach 265.31 nm / RIU and 3790.14 RIU, respectively. -1The temperature sensing sensitivity can reach 60.84 pm / ℃. Based on the linear response of the two QBIC resonance peak wavelengths of an all-dielectric metasurface, a method for simultaneous sensing of two parameters of biological components is proposed. By constructing a sensitivity sensing matrix and measuring the wavelength changes of the resonance peaks of the two quasi-BICs, the refractive index of biological components and ambient temperature can be detected simultaneously with relative errors not exceeding ±5%, achieving high-precision sensing of both refractive index and ambient temperature. This dual-resonance mode collaborative detection mechanism provides a new approach for developing high-precision multi-parameter optical biosensors and has significant application potential in the fields of biomolecular detection and environmental monitoring.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A full-metamaterial dual-QBIC structure, characterized in that, The all-dielectric metasurface dual QBIC structure, from bottom to top, includes a substrate and a silicon nanodisk. The silicon nanodisk is provided with an eccentric circular hole; The distance between the center of the silicon nanodisk and the center of the eccentric circular hole is 130-150 nm.

2. The all-dielectric metasurface double QBIC structure of claim 1, wherein, The radius R of the silicon nanodisc is 200-400 nm. 3.The all-dielectric metasurface double QBIC structure of claim 1, wherein, The height H of the silicon nanodisk is 50-200 nm.

4. The all-dielectric metasurface double QBIC structure of claim 1, wherein, The radius r of the eccentric circular hole is 20-80 nm.

5. The all-dielectric metasurface double QBIC structure of claim 1, wherein, In the all-dielectric metasurface double QBIC structure, the quality factor Q value is greater than or equal to 100. 6.The all-dielectric metasurface double QBIC structure of claim 1, wherein, The operating wavelength of the all-dielectric metasurface dual QBIC structure is 1050-1450 nm.

7. A dual-parameter biosensor based on all-dielectric metasurface dual- QBIC, characterized in that, include: An array of all-dielectric metasurface dual QBIC structures as described in any one of claims 1-6.

8. The dual-parameter biosensor based on all-dielectric metasurface dual- QBIC according to claim 7, wherein, In the array, the period of the all-dielectric metasurface dual QBIC structure is Px=Py=700-1000nm.

9. The dual-parameter biosensor based on all-dielectric metasurface dual- QBIC according to claim 7, wherein, The background refractive index of the dual-parameter biosensor based on the full-metamaterial super surface dual QBIC n B is 1.0-1.

5.

10. The application of the dual-parameter biosensor based on all-dielectric metasurface dual QBIC as described in claim 7 in the detection of refractive index of biological components and detection of ambient temperature.

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