Terahertz wave band sensing chip for detecting hepatitis B and H9N2 and application

Abstract

The invention provides a terahertz wave band sensing chip for detecting hepatitis B and H9N2 and application thereof, at least one terahertz wave band sensing unit structure, and each terahertz wave band sensing unit structure comprises a first double-hollow cylinder and a second double-hollow cylinder which are arranged on a quartz substrate at an interval, the first double-hollow cylinder and the second double-hollow cylinder are double-hollow cylinders prepared from a silicon material, the radius ratio of double hollow parts of the second double-hollow cylinder is different from the radius ratio of double hollow parts of the first double-hollow cylinder, and quasi-BIC is realized through asymmetry of the first double-hollow cylinder and the second double-hollow cylinder. High Q factors as high as 1674 and 2244 are provided respectively, and the sensitivities are as high as 110 GHz / RIU and 85 GHz / RIU respectively.

Description

Technical Field

[0001] The present invention relates to the field of optical sensing metasurfaces, and in particular to a terahertz band sensor chip and application thereof for detecting hepatitis B and H9N2. The terahertz band sensor chip is a high-sensitivity sensor chip based on silicon-silicon dioxide. Background Art

[0002] In recent years, the field of terahertz (THz) sensing has received renewed attention, driven by major advances in biosensor technology, and researchers have developed new sensing technologies that use THz radiation to detect biological samples. Various devices are used in the THz frequency range, including antennas, absorbers, sensors, spectrometers, and imaging systems for transmitting and receiving electromagnetic waves, each with different uses. THz waves can penetrate a variety of non-metallic materials, including biological tissues, without causing damage, a property that makes THz radiation ideal for non-invasive and label-free sensing of biomolecules, cells, and tissues. Various types of absorbers are designed to have different properties, and metamaterial absorbers are designed to have unique electromagnetic properties, including the ability to manipulate the absorption spectrum.

[0003] Terahertz (THz) spectroscopy has been shown to have the potential to detect nucleic acids. THz spectroscopy uses a form of radiation that lies between microwave radiation and infrared radiation in the electromagnetic spectrum. The frequency range of the radiation used here is between 0.1 and 10 THz. Nucleic acids consist of linear polymers of nucleotides linked together by phospholipid bonds. The THz spectrum of nucleic acids can be used to determine the configurational characteristics of the molecules as well as their intermolecular collective vibrations and lattice vibrations. THz time-domain spectroscopy (TDS) has been easily used to analyze nucleic acids in a label-free manner. THz biosensor chips based on metamaterials (MMs) have recently become a promising platform for protein or DNA detection. Among them, the advantage of BIC-based metamaterial sensors is that their high Q and extremely narrow peaks make them very sensitive to changes in the microenvironmental medium. However, there is currently no technical research on the detection of hepatitis B and H9N2 using THz spectroscopy. Summary of the invention

[0004] The purpose of the present invention is to provide a terahertz band sensor chip and application for detecting hepatitis B and H9N2. The characteristic that hepatitis B and H9N2 will produce specific absorption peaks in the THz frequency band can be used to design a terahertz band sensor chip for simultaneously detecting hepatitis B and H9N2.

[0005] To achieve the above objectives, the present technical solution provides a terahertz band sensor chip for detecting hepatitis B and H9N2, comprising: at least one terahertz band sensor unit structure, wherein each terahertz band sensor unit structure comprises a first double hollow cylinder and a second double hollow cylinder spaced apart on a quartz substrate, the first double hollow cylinder and the second double hollow cylinder are both double hollow cylinders made of silicon material, and the double hollow radius ratio of the second double hollow cylinder is different from the double hollow radius ratio of the first double hollow cylinder.

[0006] Compared with the prior art, this technical solution has the following characteristics and beneficial effects: The terahertz band sensor chip for detecting hepatitis B and H9N2 designed in this scheme destroys the mirror symmetry of the traditional symmetrical structure by using an asymmetric double hollow cylinder structure, thereby producing a BIC in the terahertz band. The emergence of this resonance peak enables the sensor chip to detect the presence of hepatitis B and H9N2 within a specific frequency range, improve the sensitivity and specificity of detection, and provide high Q factors of up to 1674 and 2244, which means that the system can accurately distinguish very close frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 1 is a schematic diagram of the structure of a terahertz band sensor chip for detecting hepatitis B and H9N2 according to an embodiment of the present invention.

[0008] Figure 2 It is the terahertz transmission curve of the terahertz band sensor chip when the asymmetric ratio value is 0 and 0.05.

[0009] Figure 3 It is the corresponding transmission spectrum diagram of the terahertz band sensing unit structure with different asymmetric ratio values ​​a.

[0010] Figure 4 It is a two-dimensional graph of the metasurface transmission spectrum of the terahertz band sensing unit structure of the terahertz band sensing unit structure with different asymmetric ratio values ​​a.

[0011] Figure 5 This is a curve diagram of the change in the Q factor of BIC-1 of the terahertz band sensor unit structure with different asymmetric ratio values ​​a.

[0012] Figure 6 This is a curve diagram of the change in the Q factor of the BIC-2 sensor unit structure in the terahertz band with different asymmetric ratio values ​​a.

[0013] Figure 7 The corresponding transmission spectra of the terahertz band sensing unit structure with different double hollow cylinder heights.

[0014] Figure 8Graphs showing corresponding transmission spectra of the terahertz band sensing unit structure for different radii of the first outer hollow cylinder.

[0015] Fig. 9 This is the simulated transmission spectrum under the background refractive index of 1.34.

[0016] Fig.10 This is the simulated transmission spectrum under the background refractive index of 1.38.

[0017] Fig.11 This is a schematic diagram of the effect of changes in the refractive index of the object to be measured on the sensitivity of the sensor unit structure in the terahertz band.

[0018] In the figure: 100- terahertz band sensing unit structure, 10- first double hollow cylinder, 11- first inner hollow cylinder, 12- first outer hollow cylinder, 20- second double hollow cylinder, 21- second inner hollow cylinder, 22- second outer hollow cylinder. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0020] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0021] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0022] like Figure 1 As shown, this solution provides a terahertz band sensor chip for detecting hepatitis B and H9N2, including: At least one terahertz band sensing unit structure 100, wherein each terahertz band sensing unit structure 100 includes a first double hollow cylinder 10 and a second double hollow cylinder 20 spaced apart on a quartz substrate, the first double hollow cylinder 10 and the second double hollow cylinder 20 are both double hollow cylinders made of silicon material, and the double hollow radius ratio of the second double hollow cylinder 20 is different from the double hollow radius ratio of the first double hollow cylinder 10.

[0023] The two double hollow cylinders on each terahertz band sensing unit structure designed in this scheme are asymmetric double hollow cylinders. Perturbations can be introduced by destroying the mirror symmetry of the terahertz band sensing unit structure, and BIC resonance peaks can be observed in two frequency bands of the terahertz band, thereby realizing simultaneous detection of different substances.

[0024] Specifically, the first double hollow cylinder 10 of the present scheme includes a first inner hollow cylinder 11 and a first outer hollow cylinder 12 arranged in a concentric circle manner, and the second double hollow cylinder 20 includes a second inner hollow cylinder 21 and a second outer hollow cylinder 22 arranged in a concentric circle manner, and the second inner center cylinder 21 is scaled an asymmetric ratio value relative to the first inner center cylinder 11, and the second outer hollow cylinder 22 is scaled an asymmetric ratio value relative to the first outer hollow cylinder 12.

[0025] In some embodiments, the asymmetric ratio value is set to a, the radius of the first inner hollow cylinder 11 is r2, the radius of the first outer hollow cylinder 12 is r1, the radius of the second inner hollow cylinder 21 is r4, and the radius of the second outer hollow cylinder 22 is r3. Then the relationship between the radius r4 of the second inner hollow cylinder 21 and the radius r2 of the first inner hollow cylinder 11 is: r4=r2-a*r2, and the relationship between the radius r3 of the second outer hollow cylinder 22 and the radius r2 of the first outer hollow cylinder 12 is: r3=r1-a*r1.

[0026] In some embodiments, the radius r2 of the first inner hollow cylinder 11 of the first double hollow cylinder 10 is 27-28.5 μm, and the radius r1 of the first outer hollow cylinder 12 is 54-57 μm.

[0027] In some embodiments, the radius r2 of the first inner hollow cylinder 11 is half of the radius r1 of the first outer hollow cylinder 12 .

[0028] Preferably, the radius r2 of the first inner hollow cylinder 11 of the first double hollow cylinder 10 is 27.5 μm, and the radius r1 of the first outer hollow cylinder 12 is 55 μm.

[0029] In some embodiments, the asymmetric ratio value a is a non-zero value between 0 and 0.2. Preferably, the asymmetric ratio value a is 0.05.

[0030] In some embodiments, the interval d between the first double hollow cylinder 10 and the second double hollow cylinder 20 is 25 μm.

[0031] In some embodiments, the first double hollow cylinder 10 and the second double hollow cylinder 20 have the same height, and the height is 73-93 μm. Preferably, the height h2 of the first double hollow cylinder 10 and the second double hollow cylinder 20 is 83 μm.

[0032] In addition, the present solution selects quartz as a substrate to construct a high-sensitivity sensor chip of silicon-silicon dioxide. In some embodiments, the dielectric constant of silicon is 11.9 and the dielectric constant of quartz is 3.9. In an embodiment of the present solution, the width of the square quartz substrate of the terahertz band sensing unit structure 100 is Px=275μm, the length Py is 137.5μm, the thickness h1 is 138μm, the interval d between the first double hollow cylinder 10 and the second double hollow cylinder 20 is 25μm, the height h2 of the first double hollow cylinder 10 and the second double hollow cylinder 20 is 83μm, the radius r2 of the first inner hollow cylinder 11 of the first double hollow cylinder 10 is 27.5 μm, the radius r1 of the first outer hollow cylinder 12 is 55μm, and the asymmetric ratio value is 0.05.

[0033] Of course, the terahertz band sensor chip for detecting hepatitis B and H9N2 provided by this solution includes at least two terahertz band sensor unit structures 100 arranged in an array, so that the terahertz band sensor chip for detecting hepatitis B and H9N2 can be used to detect hepatitis B and H9N2. Specifically, the aqueous solution to be tested is dripped onto the terahertz band sensor chip for detecting hepatitis B and H9N2. If a sharp valley in amplitude is detected in the frequency band of 0.77THz, the aqueous solution to be tested contains hepatitis B. If a sharp valley in amplitude is detected in the frequency band of 0.92THz, the aqueous solution to be tested contains H9N2. The terahertz band sensor chip for detecting hepatitis B and H9N2 designed in this solution can provide high Q factors of up to 1674 and 2244, respectively.

[0034] In order to verify the performance of the terahertz band sensor chip designed in this scheme for detecting hepatitis B and H9N2, the applicant team used the finite difference time domain (FDTD) solver in the electromagnetic simulation software to simulate the structure. The incident electromagnetic wave propagated along the negative z direction, the electric field was polarized along the y direction, and the boundary conditions were set to the unit cell in the x and y directions, and the open (additive space) boundary in the z direction. The simulation process was set at room temperature (T = 298.15 K), and the excitation source in the simulation was set to the TE electromagnetic wave incident from the Zmax port.

[0035] The specific performance analysis is as follows: 1. The influence of different asymmetric ratio values ​​on the structural projection rate.

[0036] A terahertz band sensing unit structure with a simulated asymmetric ratio value of 0 is simulated. At this time, the width of the square quartz substrate of the terahertz band sensing unit structure is Px=275μm, the length Py is 137.5μm, the thickness h1=138μm, the interval d between the first double hollow cylinder and the second double hollow cylinder is 25μm, the height h2 of the first double hollow cylinder and the second double hollow cylinder is 83μm, the radius r2 of the first inner hollow cylinder of the first double hollow cylinder is 27.5 μm, the radius r1 of the first outer hollow cylinder is 55μm, the radius r4 of the second inner hollow cylinder is 27.5μm, and the radius r1 of the second outer hollow cylinder is 55μm.

[0037] The terahertz band sensing unit structures with simulated asymmetric ratio values ​​a of 0.05, 0.1, 0.15, and 0.2 are simulated. At this time, the width of the square quartz substrate of the terahertz band sensing unit structure is Px=275μm, the length Py is 137.5μm, the thickness h1=138μm, the interval d between the first double hollow cylinder and the second double hollow cylinder is 25μm, the height h2 of the first double hollow cylinder and the second double hollow cylinder is 83μm, the radius r2 of the first inner hollow cylinder of the first double hollow cylinder is 27.5 μm, the radius r1 of the first outer hollow cylinder is 55μm, and the asymmetric ratio values ​​a are 0.05, 0.1, 0.15, and 0.2, respectively.

[0038] The application team used the typical Fano formula to fit the transmission spectrum of the structure:

[0039] Where q is the fitting parameter of the resonance curve asymmetry FANO, ω0 and γ are the angular frequency and resonance line width of the resonance frequency point, respectively. T0 is the transmittance baseline offset, A0 is the coupling coefficient, and the Q factor of the BIC resonance is Q=ω0 / γ.

[0040] The simulation results show that the terahertz projection curves of the terahertz band sensor unit structure with an asymmetric ratio value a of 0 and an asymmetric ratio value a of 0.05 are as follows: Figure 2 As shown, it can be seen that when the asymmetric ratio value is a = 0, two resonance peaks can be observed in the transmission spectrum, such as Figure 2 As shown by the black curve in the figure; when the asymmetric parameter is equal to a = 0.05, the structural symmetry is destroyed and the terahertz transmission curve is as follows: Figure 2 As shown by the red line in the figure, two resonance peaks (i.e., two BIC resonance peaks) are observed at frequencies of 0.77 THz and 0.92 THz, and the two resonance peaks are defined as BIC-1 and BIC-2.

[0041] The ideal BIC can be considered as a resonance with zero line width that cannot be directly observed in the spectrum. When a perturbation is introduced in the plane, the ideal BIC with infinite high Q factor transforms into a quasi-BIC mode with finite high Q factor, which is manifested by the increase of the resonance line width as the perturbation increases. The corresponding transmission spectra of the terahertz band sensing unit structure with different asymmetric ratio values ​​a are shown in Figure 3 As shown, it can be seen that when a = 0, the terahertz band sensing unit structure is in a perfectly symmetrical state, and no resonance occurs in the studied frequency band. When a is not 0, the mirror symmetry of the four hollow elliptical structures of the terahertz band sensing unit structure is broken, and a sharp Fano-type resonance peak appears in the transmission spectrum, which means that the ideal BIC is converted to a quasi-BIC mode. In order to more clearly describe the relationship between the resonance bandwidth and the asymmetry parameter a, Figure 4 shows a two-dimensional graph of the metasurface transmission spectrum of the terahertz band sensing unit structure when the parameter a changes. Figure 5 is the change of Q factor of BIC-1 of terahertz band sensing unit structure with different asymmetric ratio values ​​a, Figure 6 is the change of Q factor of BIC-2 in the terahertz band sensing unit structure with different asymmetric ratio values ​​a, from Figure 5 and Figure 6 It can be clearly seen that the bandwidth of the resonance peak gradually increases with the increase of parameter a, and its Q factor decreases.

[0042] 2. The influence of structural parameters of different heights and radii on the projected spectrum.

[0043] The terahertz band sensing unit structure with different structural parameters and the simulated asymmetric ratio value of 0.05 has a square quartz substrate with a width Px=275μm, a length Py of 137.5μm, a thickness h1=138μm, an interval d between the first double hollow cylinder and the second double hollow cylinder of 25μm, a height h2 of the first double hollow cylinder and the second double hollow cylinder of 73 / 78 / 83 / 88 / 93μm, a radius r2 of the first inner hollow cylinder of the first double hollow cylinder of 27.5 μm, a radius r1 of the first outer hollow cylinder of 55μm, a radius r4 of the second inner hollow cylinder of 26.125μm, and a radius r1 of the second outer hollow cylinder of 52.25μm.

[0044] The terahertz band sensing unit structure with different structural parameters and an asymmetric ratio value of 0.05 was simulated. The width of the square quartz substrate of the terahertz band sensing unit structure is Px=275μm, the length Py is 137.5μm, the thickness h1=138μm, the interval d between the first double hollow cylinder and the second double hollow cylinder is 25μm, the height h2 of the first double hollow cylinder and the second double hollow cylinder is 83μm, the radius r2 of the first inner hollow cylinder of the first double hollow cylinder is half of the radius r1 of the first outer hollow cylinder, and the radius r1 of the first outer hollow cylinder is 54 / 55 / 56 / 57μm.

[0045] The results of simulation tests on the terahertz band sensing unit structure with different double hollow cylinder heights h2 are shown in the figure below: Figure 7 As shown in the figure, it can be seen that the resonant transmission spectra obtained by scanning the parameters of the alignment surface height (h2) in the range of 73μm to 83μm with a step size of 5μm all have a certain degree of red shift. The results of the simulation test of the terahertz band sensor unit structure with different radii of the first outer hollow cylinder are shown in the figure. Figure 8 As shown in the figure, it can be seen that as the radius r1 of the first outer hollow cylinder increases in steps of 1 μm, the resonance also redshifts. This is because the effective refractive index (RI) of the silicon element surface increases with its height, and at the same time, the interaction between light and matter in the resonant cavity gradually increases, causing the resonance position to redshift.

[0046] 3. The impact of different simulation environments on the structure of terahertz band sensing units.

[0047] For the terahertz band sensing unit structure of metamaterials, adding the measured substance and the resulting changes in the spatial environment parameters are the main means to achieve sensing measurement, which is basically achieved by converting the difference in dielectric constant into the difference in electromagnetic signals. Therefore, the sensitivity S (S = ∆f / ∆n) that characterizes the performance of the sensor can be obtained by measuring the resonant frequency shift or refractive index (RI) changes caused by changes in spatial environment parameters, where ∆λ is the change in resonant wavelength and ∆n is the change in RI caused by environmental changes. The higher the sensitivity of the sensor, the more it can detect subtle changes in the dielectric properties of the surrounding environment.

[0048] The terahertz band sensing unit structure with a simulated asymmetric ratio value of 0.05 is shown in Figure 1. The square quartz substrate of the terahertz band sensing unit structure has a width of Px=275μm, a length of Py of 137.5μm, a thickness of h1=138μm, a spacing d between the first double hollow cylinder and the second double hollow cylinder of 25μm, a height h2 of the first double hollow cylinder and the second double hollow cylinder of 83μm, a radius r2 of the first inner hollow cylinder of the first double hollow cylinder of 27.5μm, a radius r1 of the first outer hollow cylinder of 55μm, a radius r4 of the second inner hollow cylinder of 26.125μm, and a radius r1 of the second outer hollow cylinder of 52.25μm. Taking ∆n=0.04 as an example, the background refractive index is changed, and the simulated transmission spectra under different refractive indices are obtained as follows: Fig. 9 and Fig.10 As shown, Fig. 9 The corresponding background refractive index is 1.34, Fig.10 The corresponding background refractive index is 1.38. It can be seen that the background refractive index varies between 1.34 and 1.38, and within this range, the resonance peak positions of the two modes are red-shifted as the refractive index increases. The influence of the change in the refractive index of the object to be measured on the sensitivity of the terahertz band sensor unit structure is shown in Fig.11 As shown in Figure 11, the sensing performance of the designed metasurface when the refractive index of the analyte changes from 1.34 to 1.38, the frequency shifts of BIC-1 and BIC-2 are 5 GHz and 3.5 GHz, respectively, when the refractive index changes from 1.34 to 1.38. The calculated sensitivities of BIC-1 and BIC-2 are 110 GHz / RIU and 85 GHz / RIU, respectively.

[0049] In order to comprehensively analyze the performance of the metasurface sensor, the team of this application analyzed the FOM of the metasurface, which is defined as FOM = S / FWHM, where S is the sensitivity and FWHM is the full width at half maximum of the resonant frequency. The calculated FOMs of the proposed metasurface are 239 and 207, respectively. The FOM of the sensor characterizes the overall performance of the sensor. The higher the FOM, the better the sensor performance. A high-sensitivity sensor means more light field leakage, and a high Q factor requires a strong binding ability. Therefore, sensitivity and Q factor are mutually constrained, and therefore affect the FOM. The terahertz band sensing unit structure designed by the team of this application provides high Q factors of up to 1674 and 2244, respectively, and sensitivities of up to 110 GHz / RIU and 85 GHz / RIU, respectively.

[0050] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A terahertz band sensor chip for detecting hepatitis B and H9N2, characterized in that: include: At least one terahertz band sensing unit structure, wherein each terahertz band sensing unit structure comprises a first double hollow cylinder and a second double hollow cylinder spaced apart on a quartz substrate, the first double hollow cylinder and the second double hollow cylinder are both double hollow cylinders made of silicon material, and the double hollow radius ratio of the second double hollow cylinder is different from the double hollow radius ratio of the first double hollow cylinder.

2. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 1, characterized in that: The first double hollow cylinder includes a first inner hollow cylinder and a first outer hollow cylinder arranged in a concentric circle manner, and the second double hollow cylinder includes a second inner hollow cylinder and a second outer hollow cylinder arranged in a concentric circle manner, and the second inner center cylinder is scaled an asymmetric ratio value relative to the first inner center cylinder, and the second outer hollow cylinder is scaled an asymmetric ratio value relative to the first outer hollow cylinder.

3. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 2, characterized in that: The asymmetric ratio value is a non-zero value between 0 and 0.

2.

4. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 2, characterized in that: The radius of the first inner hollow cylinder of the first double hollow cylinder is 27-28.5 μm, and the radius of the first outer hollow cylinder is 54-57 μm.

5. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 1, characterized in that: The first double hollow cylinder and the second double hollow cylinder have the same height, and the height is 73-93 μm.

6. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 2, characterized in that: The radius of the first inner hollow cylinder of the first double hollow cylinder is 27.5 μm, the radius of the first outer hollow cylinder is 55 μm, the interval between the first double hollow cylinder and the second double hollow cylinder is 25 μm, the height of the first double hollow cylinder and the second double hollow cylinder is 83 μm, and the asymmetry ratio value is 0.

05.

7. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 1, characterized in that: A plurality of terahertz band sensing unit structures are arranged in an array.

8. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 1, characterized in that: The square quartz substrate has a width of 275 μm, a length of 137.5 μm, and a thickness of 138 μm.

9. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 1, characterized in that: Non-diagnostic methods for detecting hepatitis B and H9N2.

10. The terahertz band sensor chip for detecting hepatitis B and H9N2 according to claim 9, characterized in that: The aqueous solution to be tested is dripped onto the terahertz band sensor chip used to detect hepatitis B and H9N2. If a sharp valley of amplitude is detected in the frequency band of 0.77THz, the aqueous solution to be tested contains hepatitis B. If a sharp valley of amplitude is detected in the frequency band of 0.92THz, the aqueous solution to be tested contains H9N2.

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