Metasurface sensor based on non-radiative dark state

Abstract

The invention relates to the technical field of nano photonics and metasurfaces, in particular to a metasurface sensor based on a non-radiative dark state, which comprises a quartz substrate and dumbbell-shaped slotted silicon blocks arranged on the surface of the quartz substrate periodically; the dumbbell-shaped slotted silicon block is composed of two symmetrical circular slots and a rectangular channel connecting the two circular slots, the period P of the dumbbell-shaped slotted silicon block is 600-1000 nm, the length and width p of the silicon block are 500-700 nm, the height H of the dumbbell-shaped slotted silicon block is 80-120 nm, the width a of the channel is 15-30 nm, the length b of the channel is 30-50 nm, and the radiuses R1 and R2 of the initial circular slots are 70-100 nm. The device can excite two non-radiation modes at the same time, namely, an anapole mode and a quasi-continuous domain bound state (q-BIC) mode. By designing the dielectric metasurface structure composed of the dumbbell-shaped slotted silicon block and the quartz substrate, the high Q factor and strong electric field enhancement effect is achieved, and the device not only has excellent optical performance, but also shows high sensitivity and modulation depth in multiband sensing, and is suitable for high-precision optical sensing application.

Description

Technical Field

[0001] The present invention relates to the fields of nanophotonics and metasurface technology, and specifically to a metasurface sensor based on non-radiative dark states. Background Art

[0002] As an artificially designed two-dimensional periodic sub-wavelength structure, a metasurface can flexibly manipulate the permittivity and permeability by regulating the geometric parameters of the unit structure (such as shape, size, arrangement), thereby obtaining unique electromagnetic properties. Traditional metasurface materials are mainly divided into two categories:

[0003] Metal metasurfaces: They rely on the coupled oscillation of electromagnetic fields and free electrons (plasmon resonance) to regulate electromagnetic waves. However, they have significant Ohmic losses in the visible and infrared bands, resulting in limited resonance Q factors (usually <10 3 ), and weak energy localization, severely restricting applications such as high-sensitivity sensing.

[0004] Dielectric metasurfaces: Utilizing high refractive indices (such as silicon, gallium nitride) and low-loss characteristics, they excite electric / magnetic multipole modes through Mie resonance and achieve precise localization of electromagnetic fields through collective light scattering, providing an ideal platform for the study of non-radiative dark states (such as anapole mode, bound states in the continuum BIC).

[0005] Research Status of Non-radiative Dark States

[0006] In recent years, non-radiative dark states based on dielectric metasurfaces have become a research hotspot, and their core mechanisms include:

[0007] Anapole mode: It is formed by the destructive interference of the far-field radiation of an electric dipole (ED) and a toroidal dipole (TD). When incident light excites dielectric nanoparticles, the amplitudes of the dipole moments of ED and TD are equal and the phases are opposite, resulting in the far-field radiation energy approaching zero, while the near-field energy is localized inside the structure. This mode can be indirectly observed through the narrow slit feature of the transmission spectrum (line width <5 nm) and exhibits high sensitivity (~200 nm / RIU) in the sensing field. However, its Q factor is limited by mode leakage (Q <10 3 ), and it is difficult for a single mode to balance sensitivity and detection accuracy.

[0008] Bound states in the continuum (BIC): Initially proposed in quantum mechanics and later introduced into the field of photonics. Due to the symmetry mismatch with the radiation channel, the BIC mode theoretically has an infinite Q factor and vanishing radiation losses. Symmetry-protected BIC (SP-BIC) is a typical representative, which is realized through the symmetry design of the metasurface periodic structure. However, due to strict symmetry requirements, it cannot be directly excited and needs to be transformed into a quasi-BIC (q-BIC) mode by introducing asymmetry. Although the q-BIC mode retains a high Q factor (>104 ) and strong near-field localization, but its sensitivity is usually lower than that of the anapole mode (~150 nm / RIU), and the flexibility of structural parameter regulation is insufficient.

[0009] Limitations of the prior art

[0010] Mode singularity: Most existing metasurface sensors focus on a single non-radiative dark state (only anapole or only BIC), and it is impossible to simultaneously achieve the synergistic advantages of high sensitivity (anapole characteristics) and high Q factor (BIC characteristics);

[0011] Rigid structural design: Traditional q-BIC modes rely on complex periodic structures (such as nanocolumn arrays) to achieve symmetry breaking, with a narrow parameter adjustment range (such as asymmetry ΔR < 20 nm), making it difficult to dynamically balance the Q factor and sensing performance;

[0012] Material and fabrication bottlenecks: The ohmic loss problem of metal metasurfaces, the processing accuracy requirements of dielectric metasurfaces (such as the silicon layer thickness error needs to be < ±10 nm) and substrate roughness control (< 1 nm) limit large-scale applications;

[0013] Lack of multimodal detection: Single-resonant wavelength detection is vulnerable to environmental noise interference, and it is impossible to improve reliability through multi-band data fusion (error > ±10%). Summary of the invention

[0014] (1) Technical problems to be solved

[0015] Aiming at the deficiencies of the prior art, the present invention provides a metasurface sensor based on non-radiative dark states.

[0016] (2) Technical solutions

[0017] To achieve the above object, the present invention provides the following technical solutions: A metasurface sensor based on non-radiative dark states of the present invention includes:

[0018] A quartz substrate and periodically arranged dumbbell-shaped grooved silicon blocks disposed on its surface;

[0019] The dumbbell-shaped grooved silicon block is composed of two symmetric circular grooves and a rectangular channel connecting the two, with a period P of 600 - 1000 nm, the length and width p of the silicon block being 500 - 700 nm, the height H being 80 - 120 nm, the channel width a being 15 - 30 nm, the channel length b being 30 - 50 nm, and the initial circular groove radii R1 and R2 both being 70 - 100 nm;

[0020] By adjusting the size of R2 to break the structural symmetry, simultaneously exciting the anapole mode and the quasi-bound state in the continuum (q-BIC) mode, where:

[0021] The anapole mode is generated by the cancellation of the interference between the electric dipole (ED) and the toroidal dipole (TD). The energy is localized in the channel region, and the electric field enhancement factor is more than 100 times;

[0022] The q-BIC mode is induced by symmetry breaking, and the dominant multipole is the electric quadrupole (EQ). The energy is localized at the four corners of the silicon block, the Q factor reaches more than 10^4, and the modulation depth exceeds 95%;

[0023] The metasurface realizes multi-band refractive index sensing through the wavelength shift of multiple resonant valleys in the transmission spectrum. The sensitivity range is 200 - 400 nm / RIU, and the figure of merit (FOM) is higher than 10^3.

[0024] Preferably, the periodically arranged unit structures satisfy one of the following conditions:

[0025] The ratio of the period P to the length p of the silicon block is 1.1 - 1.5;

[0026] The ratio of the channel width a to the length b is 0.4 - 0.7;

[0027] The difference ΔR between R2 and R1 is 5 - 50 nm, which is used to regulate the Q factor of the q-BIC mode.

[0028] Further preferably, the silicon block is formed by chemical vapor deposition of single crystal silicon with a purity higher than 99.999%, and the processing error of its thickness H is less than ±5 nm; the surface roughness of the quartz substrate is less than 0.5 nm.

[0029] Most preferably, a microfluidic chamber is provided in the quartz substrate. The microfluidic chamber includes a liquid inlet and a liquid outlet. The height of the microfluidic pore cavity is 10 - 100 μm, and the distance from the surface of the quartz substrate is 1 - 10 μm, which is used to change the refractive index of the medium around the metasurface by injecting the liquid to be measured.

[0030] Preferably, a preparation method of a metasurface sensor for an application of a metasurface sensor based on a non-radiative dark state includes the following steps:

[0031] S1. Deposit a crystalline silicon layer with a thickness of 80 - 120 nm on the quartz substrate, the deposition temperature is 500 - 800 °C, and the air pressure is 10 - 100 Pa;

[0032] S2. Use focused ion beam etching (FIB) to process a dumbbell-shaped slotted structure. The ion beam energy is 30 - 50 keV, the beam current intensity is 1 - 10 pA, and the etching positioning accuracy is better than ±2 nm;

[0033] S3. Introduce the asymmetry parameter ΔR by adjusting the size of R2, so that the Q factor of the q-BIC mode and ΔR satisfy the relationship: Q ∝ 1 / ΔR^2.

[0034] Further preferably, in the step S2, the structure is processed by two etching steps: the first etching is for the circular slotted area, and the ion beam dwell time is 0.1 - 1 ms / pixel; the second etching is for the rectangular channel, and the dwell time is 0.05 - 0.5 ms / pixel.

[0035] Again preferably, according to a multi-wavelength detection method of a metasurface sensor for applications of a metasurface sensor based on non-radiative dark states, it includes:

[0036] Inject the liquid to be measured into the microfluidic chamber, and collect the resonant wavelengths of λ1 (corresponding to the anapole mode) and λ2 (corresponding to the q-BIC mode) in the transmission spectrum;

[0037] Calculate the refractive index change amount Δn through the formulas Δλ1 = S1·Δn and Δλ2 = S2·Δn, where S1 and S2 are the sensitivities of the two modes respectively;

[0038] Output the final refractive index value based on the average value of the dual-mode measurement results, and its relative error is less than ±5%.

[0039] Preferably, when the refractive index of the liquid to be measured in the microfluidic chamber is in the range of 1.33 - 1.37, the sensitivity S1 of the anapole mode is 250 - 350 nm / RIU, and the sensitivity S2 of the q-BIC mode is 300 - 400 nm / RIU.

[0040] (III) Beneficial effects

[0041] Compared with the prior art, the present invention provides a metasurface sensor based on non-radiative dark states, having the following beneficial effects:

[0042] Dual-mode collaborative enhancement of sensing performance

[0043] Anapole mode: Through the interference cancellation of the electric dipole (ED) and the toroidal dipole (TD), the energy is localized in the middle channel area of the dumbbell-shaped slot, realizing an electric field enhancement of more than 100 times, and significantly improving the sensitivity to local refractive index changes;

[0044] q-BIC mode: By adjusting the size of R2 (ΔR = 5 - 50 nm) to break the structural symmetry, a quasi-bound state in the continuum with a high Q factor (>10 4 ) and a high modulation depth (>95%) is excited, and the energy is localized at the four corner tips of the silicon block, providing a detection window with a narrow linewidth and low noise;

[0045] Synergistic advantages: Dual-mode multi-band detection (λ1 = 1213 nm, λ2 = 1290 nm) combines the high sensitivity of anapole (250 - 350 nm / RIU) with the high precision of q-BIC (Q factor up to 10 4 ), and the comprehensive figure of merit (FOM = S × Q / linewidth) breaks through 10 3 , achieving a detection limit as low as 10 -6 RIU, with an error rate < ±5%.

[0046] Optimization of structural parameters enhances energy localization

[0047] Period-to-size ratio: The ratio of the period P (600 - 1000 nm) to the length p of the silicon block (500 - 700 nm) is 1.1 - 1.5, balancing Bragg scattering and local mode field coupling and suppressing spurious mode interference;

[0048] Channel width-to-length ratio: a / b = 0.4 - 0.7 (a = 15 - 30 nm, b = 30 - 50 nm) optimizes the interference efficiency of ED and TD, making the electric field enhancement factor of the anapole mode stable > 100 times;

[0049] Symmetry regulation: The difference ΔR (5 - 50 nm) between R2 and R1 precisely regulates the Q factor of the q-BIC mode (Q ∝ 1 / ΔR 2 ), achieving an adjustable range of Q values from 10 3 to 10 4 to adapt to the requirements of different sensing scenarios.

[0050] Multi-wavelength detection method

[0051] Dual-mode data fusion: Collect the resonant wavelength shifts Δλ1 and Δλ2 of λ1 (anapole) and λ2 (q-BIC), and calculate the refractive index change through the formula Δn = (Δλ1 / S1 + Δλ2 / S2) / 2, reducing the error rate to below ±5%;

[0052] High-sensitivity range: In the refractive index range of 1.33 - 1.37, the sensitivity of the anapole mode S1 = 250 - 350 nm / RIU, and the q-BIC mode S2 = 300 - 400 nm / RIU, covering the detection requirements of biological fluids (such as serum n ≈ 1.35) and chemical reagents (n = 1.33 - 1.45). Brief description of the drawings

[0053] Figure 1 is the overall structural schematic diagram of the present invention;

[0054] Figure 2 is the cross-sectional structural schematic diagram of the quartz substrate of the present invention;

[0055] Figure 3Transmission spectrum and resonance characteristic diagram of the present invention;

[0056] Figure 4 Schematic diagram of the transmission spectrum of the present invention under different R2 values;

[0057] Figure 5 When R2 = 80nm in the present invention, electromagnetic field distribution diagram of exciting anapole mode at λ1';

[0058] Figure 6 When R2 = 100nm in the present invention, electromagnetic field distribution diagrams of exciting anapole mode and q-BIC mode at λ1 and λ2;

[0059] Figure 7 Influence diagram of adjusting geometric parameters on optical performance of the present invention;

[0060] Figure 8 Schematic diagram of the design of a metasurface sensor based on a microfluidic device of the present invention;

[0061] In the figure: 1. Quartz substrate; 2. Dumbbell-shaped grooved silicon block; 3. Circular groove; 4. Rectangular channel; 5. Microfluidic chamber; 6. Liquid inlet; 7. Liquid outlet. Detailed implementation manners

[0062] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0063] Please refer to Figure 1-8 , a metasurface sensor based on a non-radiative dark state of the present invention includes:

[0064] A quartz substrate 1 and periodically arranged dumbbell-shaped grooved silicon blocks 2 disposed on its surface;

[0065] The dumbbell-shaped grooved silicon block 2 is composed of two symmetric circular grooves 3 and a rectangular channel 4 connecting the two. Its period P is 600 - 1000nm, the length and width p of the silicon block are 500 - 700nm, the height H is 80 - 120nm, the channel width a is 15 - 30nm, the channel length b is 30 - 50nm, and the initial radii R1 and R2 of the circular grooves 3 are both 70 - 100nm;

[0066] By adjusting the size of R2 to break the structural symmetry and simultaneously excite anapole mode and quasi-bound state in the continuum (q-BIC) mode, where:

[0067] The anapole mode is generated by the cancellation of the interference between the electric dipole (ED) and the toroidal dipole (TD). The energy is localized in the channel region, and the electric field enhancement factor is greater than 100 times.

[0068] The q-BIC mode is induced by symmetry breaking. The dominant multipole is the electric quadrupole (EQ). The energy is localized at the four corners of the silicon block, the Q factor reaches more than 10^4, and the modulation depth exceeds 95%.

[0069] The metasurface realizes multi-band refractive index sensing through the wavelength shift of multiple resonant valleys in the transmission spectrum. The sensitivity range is 200 - 400 nm / RIU, and the figure of merit (FOM) is higher than 10^3.

[0070] The metasurface sensor based on the non-radiative dark state can simultaneously excite the anapole mode and the q-BIC mode. By designing the metasurface structure composed of the dumbbell-shaped slotted silicon block 2 and the quartz substrate 1, high Q factor and strong electric field enhancement effect are achieved, which is suitable for high-precision optical sensing applications. The following is the description of its working principle:

[0071] Non-radiative dark state co-excitation mechanism

[0072] The metasurface sensor realizes high-sensitivity sensing based on the synergistic effect between the anapole mode and the quasi-bound state in the continuum (q-BIC) mode in the dielectric metasurface:

[0073] Anapole mode: Formed by the destructive interference of the radiation between the electric dipole (ED) and the toroidal dipole (TD). When the incident light excites the silicon block structure, the far-field radiation powers of the ED and the TD are equal and in opposite phases, resulting in the far-field radiation energy approaching zero, and the near-field energy is localized in the middle channel region of the dumbbell-shaped structure, forming an ultra-strong electric field (enhancement factor > 100 times), which significantly improves the sensitivity to the local refractive index change.

[0074] q-BIC mode: By breaking the symmetry of the dumbbell-shaped structure (adjusting the difference ΔR between R2 and R1), the originally dark BIC mode is transformed into an observable q-BIC mode. Its dominant multipole is the electric quadrupole (EQ), and the energy is localized at the tips of the four corners of the silicon block, and the Q factor is as high as 10 4 Above, the modulation depth exceeds 95%, providing a basis for narrow linewidth and high-precision sensing.

[0075] Multi-band refractive index sensing principle

[0076] When the liquid to be measured contacts the metasurface through the microfluidic chamber 5, the change in the environmental refractive index (Δn) causes the change in the local field distribution, resulting in the red shift of the anapole (λ1) and q-BIC (λ2) resonant valleys in the transmission spectrum;

[0077] The sensitivity (S) is defined as the ratio of the wavelength shift to the refractive index change (S = Δλ / Δn). The sensing accuracy is improved through dual-mode collaborative measurement (S1 = 250 - 400 nm / RIU, S2 = 300 - 400 nm / RIU) and FOM (S×Q / linewidth), and the total error is < ±8%.

[0078] By functionalizing the surface of the silicon block with antibodies or DNA probes, the binding of target molecules causes a local refractive index change, and the detection limit reaches 10^-18 M.

[0079] Working principle of the preferred technical solution

[0080] Structure optimization solution

[0081] Period-to-size ratio: The ratio of the period P to the length p of the silicon block (1.1 - 1.5) ensures the balance between the Bragg scattering effect of the metasurface periodic arrangement and the coupling of the local mode field; the channel aspect ratio a / b = 0.4 - 0.7 optimizes the interference efficiency of ED and TD and enhances the electric field localization of the anapole mode.

[0082] Symmetry-breaking regulation: By adjusting the size of R2 (ΔR = 5 - 50 nm), controllable asymmetry is introduced, and the Q factor of the q-BIC mode is inversely proportional to ΔR 2 (Q ∝ 1 / ΔR 2 ) to achieve an adjustable range of Q values from 10 3 to 10 4 to meet the requirements of different application scenarios.

[0083] Material and preparation solution

[0084] High-purity single-crystalline silicon (>99.999%): Reducing the ohmic loss caused by impurities, ensuring low absorption and high refractive index (n ≈ 3.5) in the near-infrared band (1200 - 1300 nm), and enhancing mode localization;

[0085] Atomically flat quartz substrate 1 (roughness < 0.5 nm): Avoiding lattice distortion during silicon layer deposition, ensuring the geometric accuracy of the structure (dimension error < ±5 nm), and suppressing the random drift of the resonant wavelength.

[0086] Microfluidic integration solution

[0087] Chamber height (10 - 100 μm) and metasurface spacing (1 - 10 μm): Achieving rapid liquid filling through capillary action and pressure driving, while restricting the liquid volume to enhance the near-field interaction;

[0088] Dual-mode data fusion algorithm: Based on the high electric field enhancement (S1) of the anapole mode and the high Q value (S2) of the q-BIC mode, the weighted average method (error < ±5%) is used to reduce the influence of environmental noise.

[0089] Detailed Workflow

[0090] Step 1: Metasurface Fabrication

[0091] Substrate Treatment: Clean the fused silica substrate 1 (thickness 1 mm), remove surface contaminants by plasma etching to make the roughness < 0.5 nm;

[0092] Silicon Layer Deposition: Deposit a 90-nm monocrystalline silicon layer on the quartz substrate 1 with silane (SiH4) as the precursor by CVD method at 500 - 800 °C and 10 - 100 Pa, with a thickness error < ±5 nm;

[0093] Structure Etching:

[0094] Circular Grooving 3: Use FIB technology (ion beam energy 30 - 50 keV, beam current 1 - 10 pA) to etch the R1 and R2 regions, with a dwell time of 0.1 - 1 ms / pixel;

[0095] Rectangular Channel 4: Secondarily etch the middle channel (width a = 20 nm, length b = 40 nm), with a dwell time of 0.05 - 0.5 ms / pixel and a positioning accuracy of ±2 nm;

[0096] Step 2: Microfluidic Integration

[0097] Chamber Bonding: Bond the PDMS microfluidic layer on the surface of the quartz substrate 1 to form a chamber with a height of 10 - 100 μm and an inlet / outlet aperture of 50 - 100 μm;

[0098] Spacing Control: Regulate the spacing between the bottom of the chamber and the metasurface (1 - 10 μm) by nanoimprint technology to avoid liquid flow disturbing the structure;

[0099] Step 3: Sensing Detection

[0100] Liquid Injection: Inject the liquid to be measured (refractive index 1.33 - 1.37) into the chamber at a flow rate of 1 - 10 μL / min and let it stand for 30 seconds until stable;

[0101] Spectrum Acquisition: Use a white light source (wavelength range 1000 - 1500 nm) to irradiate the metasurface and record the transmission spectrum through an optical fiber spectrometer;

[0102] Data Analysis:

[0103] Extract the resonant wavelengths of λ1 (anapole mode, around 1213 nm) and λ2 (q - BIC mode, around 1290 nm);

[0104] Calculate Δλ1 = S1·Δn and Δλ2 = S2·Δn, and take the average of the two modes as the final refractive index value;

[0105] Error correction: The result is corrected according to the preset temperature and humidity compensation curve (25 ± 1 °C, humidity 40 - 60%) and the instrument calibration data (wavelength error ± 1 nm).

[0106] Material details and test environment

[0107] Material details:

[0108] The single crystal silicon used is (100)-oriented single crystal silicon, and its purity reaches more than 99.9999%.

[0109] The fused silica substrate 1 has a thickness of 1 mm, and the surface flatness reaches an AFM root mean square roughness of less than 0.5 nm.

[0110] Test environment and error analysis:

[0111] Test environment conditions: The sensing performance test is carried out in a constant temperature and humidity laboratory environment with a temperature of 25 ± 1 °C and a relative humidity of 40% - 60%.

[0112] Instrument error: The wavelength accuracy and transmittance measurement accuracy of the spectrometer will introduce errors. After calibration, the wavelength error is controlled within ±1 nm, and the transmittance measurement error is within ±0.5%.

[0113] Sample preparation error: Tiny deviations in the structural dimensions will affect the resonant characteristics. It is estimated that the influence of this error on the sensing sensitivity and quality factor is within ±5%.

[0114] Environmental factor error: The influence of temperature and humidity changes on the test results is within ±3%. Considering all error factors, the total error of the final sensing performance test results is within ±8%.

[0115] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metasurface sensor based on a non-radiative dark state, characterized in that: include: A quartz substrate (1) and periodically arranged dumbbell-shaped grooved silicon blocks (2) arranged on the surface of the quartz substrate; The dumbbell-shaped slotted silicon block (2) is composed of two symmetrical circular slots (3) and a rectangular channel (4) connecting the two, wherein the period P is 600-1000 nm, the length and width p of the silicon block are 500-700 nm, the height H is 80-120 nm, the channel width a is 15-30 nm, the channel length b is 30-50 nm, and the radii R1 and R2 of the initial circular slots (3) are both 70-100 nm; By adjusting the size of R2, the structural symmetry is broken, and the anapole mode and the quasi-continuum bound state (q-BIC) mode are excited simultaneously, where: The anapole mode is generated by the destructive interference of the electric dipole (ED) and the toroidal dipole (TD), with the energy localized in the channel region and the electric field enhancement factor greater than 100 times; The q-BIC mode is induced by symmetry breaking, with the dominant multipole being the magnetic quadrupole (EQ), with energy localized at the four corners of the silicon block, a Q factor of more than 10^4, and a modulation depth of more than 95%; The metasurface achieves multi-band refractive index sensing by wavelength shifting of multiple resonant troughs in the transmission spectrum, with a sensitivity range of 200-400nm / RIU and a quality factor (FOM) higher than 10^3.

2. The metasurface sensor based on the non-radiative dark state according to claim 1, characterized in that: The periodically arranged unit structure satisfies one of the following conditions: The ratio of the period P to the silicon block length p is 1.1-1.5; The ratio of channel width a to length b is 0.4-0.7; The difference ΔR between R2 and R1 is 5-50nm, which is used to adjust the Q factor of the q-BIC mode.

3. The metasurface sensor based on the non-radiative dark state according to claim 2, characterized in that: The dumbbell-shaped slotted silicon block (2) is formed by chemical vapor deposition of single crystal silicon with a purity higher than 99.999%, and the processing error of its thickness H is less than ±5nm; the surface roughness of the quartz substrate (1) is less than 0.5nm.

4. The metasurface sensor based on the non-radiative dark state according to claim 3, characterized in that: A microfluidic chamber (5) is provided in the quartz substrate (1), the microfluidic chamber (5) comprising a liquid inlet (6) and a liquid outlet (7), the microfluidic chamber (5) having a height of 10-100 μm and a surface distance of 1-10 μm from the quartz substrate (1), and being used for changing the refractive index of the medium surrounding the metasurface by injecting a liquid to be tested.

5. The method for preparing a metasurface sensor based on a non-radiative dark state metasurface sensor according to claim 4, characterized in that: The following steps are involved: S1, depositing a crystalline silicon layer with a thickness of 80-120 nm on a quartz substrate (1), at a deposition temperature of 500-800° C. and a gas pressure of 10-100 Pa; S2, using focused ion beam etching (FIB) to process dumbbell-shaped slotted structures, with an ion beam energy of 30-50keV, a beam current of 1-10pA, and an etching positioning accuracy better than ±2nm; S3. By adjusting the size of R2, an asymmetric parameter ΔR is introduced so that the Q factor of the q-BIC mode satisfies the relationship between ΔR: Q∝1 / ΔR^2.

6. The method for preparing a supersurface sensor according to claim 5, characterized in that: In the step S2, the structure processing is completed by etching twice: the first etching of the circular slot (3) area, the ion beam residence time is 0.1-1ms / pixel; the second etching of the rectangular channel (4), the residence time is 0.05-0.5ms / pixel.

7. The multi-wavelength detection method of a metasurface sensor based on a non-radiative dark state metasurface sensor according to claim 4, characterized in that: include: Injecting the liquid to be tested into the microfluidic chamber (5), and collecting the resonance wavelengths of λ1 (corresponding to the anapole mode) and λ2 (corresponding to the q-BIC mode) in the transmission spectrum; The refractive index change Δn is calculated by the formula Δλ1=S1·Δn and Δλ2=S2·Δn, where S1 and S2 are the sensitivities of the two modes respectively; The final refractive index value is output based on the average of the dual-mode measurement results, with a relative error of less than ±5%.

8. The multi-wavelength detection method of the metasurface sensor according to claim 7, characterized in that: When the refractive index of the liquid to be measured in the microfluidic chamber (5) is in the range of 1.33-1.37, the sensitivity S1 of the anapole mode is 250-350 nm / RIU, and the sensitivity S2 of the q-BIC mode is 300-400 nm / RIU.

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