An ultra-highly sensitive terahertz antibiotic sensor based on a petal structure

Abstract

This solution provides an ultra-high-sensitivity terahertz antibiotic sensor based on a petal structure, comprising: at least one array-arranged sensing unit; each sensing unit comprises a graphene layer and a dielectric layer from top to bottom, wherein two identical resonators are formed on the graphene layer, and each resonator is designed as a petal structure comprising an inner ring and an inner ring, and the two resonator structures are staggered. Through the unique petal structure design combined with the unique electronic properties of graphene materials and the EIT effect, the problem of insufficient detection accuracy of traditional EIT sensors under high-sensitivity conditions is solved.

Description

Technical Field

[0001] The present invention relates to the field of terahertz sensing technology, and in particular to an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure. Background Art

[0002] Terahertz waves, which lie between microwaves and infrared light, possess unique penetrating and non-ionizing properties, giving them enormous potential for application in fields such as biomedical testing, environmental monitoring, security inspections, and communications. In particular, in biomolecular detection, terahertz technology can accurately detect trace amounts of substances by identifying the characteristic absorption peaks of molecules. The electromagnetically induced transparency (EIT) effect, a quantum interference phenomenon generated by the interaction of electromagnetic waves, was first discovered in atomic systems and manifests as a narrow transparency window in the absorption spectrum accompanied by significant dispersion enhancement. In recent years, the EIT effect has shown broad application potential in fields such as optical sensing, optical switching, and quantum information processing. By incorporating the EIT effect into metamaterial design, researchers can achieve precise control of electromagnetic waves, thereby improving the sensitivity and selectivity of sensors.

[0003] However, traditional EIT sensors face the following drawbacks:

[0004] 1. The challenge of balancing sensitivity and Q: Existing terahertz sensors often experience reduced detection accuracy when pursuing high sensitivity. This is particularly true when detecting trace substances, making it difficult to achieve an effective balance between high sensitivity and a high quality factor (Q). Specifically for EIT sensors, the Q factor often decreases under high sensitivity conditions, resulting in insufficient detection accuracy. This presents a key technical challenge in EIT sensor research. For example, some existing multi-band filters, due to structural design limitations, have a relatively fixed number of passbands and frequency ranges and lack reconfigurability. While research has explored the use of active components such as variable capacitance diodes to control frequency, existing technologies still have limited frequency reconfiguration capabilities, making them difficult to meet the demands of multi-frequency signal processing in complex communication environments.

[0005] 2. Fixed structure and lack of adjustability: Traditional EIT sensor structures usually use metal or dielectric materials, with a relatively fixed design, making it difficult to achieve dynamic adjustment, which limits its application in complex environments.

[0006] 3. Material limitations: Traditional EIT sensor structures usually use metal or dielectric materials, which have large losses in the terahertz band, further affecting the performance of the sensor. Summary of the Invention

[0007] The purpose of the present invention is to provide an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure. Through the unique petal structure design combined with the unique electronic properties of graphene materials and the EIT effect, the problem of insufficient detection accuracy of traditional EIT sensors under high sensitivity conditions is solved.

[0008] To achieve the above objectives, the present technical solution provides an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure, comprising:

[0009] At least one array of sensor units;

[0010] Each sensing unit includes a graphene layer and a dielectric layer from top to bottom, wherein two identical resonators are formed on the graphene layer, and each resonator is designed to include an inner ring and a petal structure of the inner ring, and the two resonator structures are staggered.

[0011] Compared with the existing technology, this technical solution has the following characteristics and beneficial effects:

[0012] The petal-structured ultra-high-sensitivity terahertz antibiotic sensor provided in this solution can achieve a balance between high sensitivity and high Q value. The present invention significantly enhances the electric field strength through the design of the petal structure and realizes the EIT effect through near-field coupling, so that the sensor forms a sharp EIT window at 1.0 THz with a window linewidth of only 0.05 THz. This design enables the sensor to achieve a Q value of 20.8 while maintaining high sensitivity (1.225 THz / RIU), solving the problem of Q value decline of traditional EIT sensors under high sensitivity conditions. The petal-structured ultra-high-sensitivity terahertz antibiotic sensor provided in this solution exhibits excellent sensing performance under both vertical and horizontal polarization conditions, can effectively separate signals and select frequencies, and is suitable for antibiotic molecule detection in complex environments.

[0013] Furthermore, the petal-structured, ultra-high-sensitivity terahertz antibiotic sensor proposed in this solution can detect and process signals at different frequencies, making it suitable for multi-frequency signal processing in complex environments. By adjusting the graphene's Fermi level, the sensor can be dynamically controlled, making it suitable for multi-channel communication systems or applications requiring multi-frequency signal processing. This multi-frequency signal processing capability holds broad application prospects in biomedical testing, environmental monitoring, and communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the unit structure of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0015] Figure 2This is a schematic diagram of the array layout of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0016] Figure 3 This is a schematic diagram of the EIT mechanism analysis of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed in the present invention.

[0017] Figure 4 This is the electric field diagram at the resonant frequency of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0018] Figure 5 This is a transmission curve diagram of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention under different polarization directions.

[0019] Figure 6 The figure is a curve diagram showing the influence of the thickness d of the dielectric plate on the transparent window of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0020] Figure 7 This is a curve diagram showing the influence of the coupling distance s of the ultra-high sensitivity terahertz antibiotic sensor based on the petal structure designed by the present invention on the transparent window.

[0021] Figure 8 This is a transmission curve diagram generated by the Fermi level change of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0022] Figure 9 This is a window frequency diagram corresponding to different Fermi energy levels of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0023] Figure 10 This is a transmission curve diagram corresponding to different refractive indices under x-polarization for an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0024] Figure 11 This is a window frequency diagram corresponding to different refractive indices of an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention under x-polarization.

[0025] Figure 12 This is a transmission curve diagram corresponding to different refractive indices under y-polarization for an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention.

[0026] Figure 13 This is a window frequency diagram corresponding to different refractive indices under y-polarization for an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure designed by the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0028] It should be understood by those skilled in the art that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "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 accompanying 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.

[0029] Example 1

[0030] like Figure 1 As shown, this scheme provides an ultra-high sensitivity terahertz antibiotic sensor based on a petal structure, comprising:

[0031] At least one array of sensor units;

[0032] Each sensing unit includes a graphene layer and a dielectric layer from top to bottom, wherein two identical resonators are formed on the graphene layer, and each resonator is designed to include an inner ring and a petal structure of the inner ring, and the two resonator structures are staggered.

[0033] In this scheme, the two petal-structured resonators on each sensing unit constitute the resonant part, and the two identical resonators can produce a symmetrical electromagnetic field distribution at a specific frequency, forming a sharp EIT window through frequency detuning and phase interference. If only a single resonator is used, the energy level transition and coupling effect required for the transparent window cannot be achieved.

[0034] In some embodiments, the centers of the inner ring and the outer ring in each resonator of the present invention overlap and are spaced apart. In other words, the inner ring and the outer ring in each resonator of the present invention are arranged in the form of concentric rings.

[0035] In some embodiments, the inner and outer rings are the same shape.

[0036] In some embodiments, the inner ring is a closed loop formed by connecting at least two curved segments end-to-end, with each curved segment having the same curvature, and adjacent curved segments connecting to form a concave point on the inner ring. Similarly, the outer ring is also a closed loop formed by connecting at least two curved segments end-to-end, with each curved segment having the same curvature, and adjacent curved segments connecting to form a concave point on the outer ring.

[0037] Specifically, each curved segment on the inner ring is an arc segment that bulges outward relative to the center of the inner ring, and the arc center of the curved segment does not overlap with the center of the inner ring. This arrangement allows each curved segment to form a petal of the inner ring. Similarly, each curved segment on the outer ring is an arc segment that bulges outward relative to the center of the outer ring, and the arc center of the curved segment does not overlap with the center of the outer ring.

[0038] Furthermore, each curved segment of the inner ring corresponds to each curved segment of the outer ring one-to-one, that is, the arc center of each curved segment of the inner ring, the arc center of the outer ring and the center of the resonator are located in the same radial direction.

[0039] That is, the inner ring of each resonator in this solution is a small petal pattern, the outer ring is a large petal pattern, each curved segment on the inner ring forms a petal leaf of the inner ring, and each curved segment on the outer ring forms a petal leaf of the outer ring.

[0040] In some specific embodiments, four curved segments are provided on the inner ring, and four curved segments are also provided on the outer ring, and the four curved segments are provided in a one-to-one correspondence.

[0041] In a specific embodiment, the maximum distance R2 from the curved section on the outer ring of the same resonator to the center of the outer ring is 17 μm, and the minimum distance r2 from the curved section on the outer ring to the center of the outer ring is 11 μm, that is, the distance r2 from the concave point on the curved section on the outer ring to the center of the outer ring is 11 μm. At the same time, the maximum distance R1 from the curved section on the inner ring to the center of the inner ring is 7.5 μm, and the minimum distance r1 from the curved section on the inner ring to the center of the inner ring is 4.8 μm, that is, the distance r1 from the concave point on the curved section on the inner ring to the center of the inner ring is 4.8 μm. The advantage of this arrangement is that it can form a sharp petal concave point on the inner ring, so that the electric field at the concave point position can be greatly enhanced. Generally speaking, the sharper the concave point, the more significant the local enhancement effect of the electric field, thereby improving the resonance strength and Q value; at the same time, the outer ring and the inner ring are spaced apart to ensure that the outer ring can form effective near-field coupling with the inner ring, while avoiding excessive overlap of electromagnetic field distribution and causing the resonance frequency to shift.

[0042] It should be noted that the dielectric layer is a quartz plate with a relative dielectric constant of 1.9. In one specific embodiment, the dielectric layer is a square with equal length and width, and both the length and width are 72 μm. This configuration has the advantage of suppressing mutual interference between adjacent resonators. If the side length of the quartz plate is too small, the electromagnetic fields of adjacent units will interfere with each other, impairing the EIT effect. If the side length of the quartz plate is too large, the sensor's integration density will be reduced.

[0043] In some embodiments, the thickness d of the dielectric layer is 5 to 12 μm. Preferably, the thickness d of the dielectric layer is 10 μm. When the dielectric layer thickness d = 10 μm, the bandwidth is compressed to 0.05 THz (Q = 20.8), meeting the requirements of high-precision detection. The transmittance drop is controllable, surpassing the performance when d = 12 μm. The peak frequency redshift is moderate, well matching the 1.0 THz fingerprint peak of chlortetracycline. This value is the core parameter after simulation optimization, ensuring the sensor achieves the optimal balance between sensitivity (1.225 THz / RIU) and detection accuracy (Q = 20.8).

[0044] In some embodiments, the thickness of the graphene layer is 0.001 μm, ie, the thickness of the two resonators is 0.001 μm.

[0045] In addition, the two resonators on each sensing unit of this solution are arranged adjacent to each other with a gap between them. Specifically, in some embodiments, the line connecting the resonance centers of the two resonators is arranged obliquely relative to the dielectric layer, that is, one resonator is located in the oblique direction of the other resonator.

[0046] In a specific embodiment, the minimum distance w between the two resonators is 2 μm. The advantage of this setting is that the current path can be optimized. The width of 2 μm can support the efficient transmission of high-frequency current on the graphene surface while avoiding electric field dispersion caused by excessive width.

[0047] Specifically, the two resonators are located at diagonal positions of the dielectric layer. One resonator can be located at the lower left corner of the dielectric layer, and the other resonator can be located at the upper right corner of the dielectric layer; or one resonator can be located at the upper left corner of the dielectric layer, and the other resonator can be located at the lower right corner of the dielectric layer. The shortest distance between the two resonators is 2 μm. Specifically, each resonator has four identical curved segments, and the distance between the curved segment above one resonator and the curved segment below the other resonator is the shortest distance between the two resonators.

[0048] In some embodiments, the coupling distance s between two resonators is 2-5 μm. It should be noted that the coupling distance between resonators refers to the minimum distance between the two resonators.

[0049] Preferably, the coupling distance s is 2.98. The advantage of this setting is that the electric field overlap area between the two resonators is maximized to achieve strong coupling. When the coupling distance s>5μm, the coupling effect is significantly weakened and the EIT window transmittance decreases. If the coupling distance s is less than 2μm, stray capacitance interference may occur.

[0050] As mentioned above, the resonator on the petal-structured ultra-high-sensitivity terahertz antibiotic sensor designed in this scheme is designed as a double-petal structure. The petal-shaped resonator, due to its unique geometric structure, can concentrate the electromagnetic field energy at the concave points of the petals, significantly enhancing the local electric field strength. This design not only improves the sensitivity of the sensor, but also realizes the energy level transition from the ground state to the transparent state through near-field coupling, forming a sharp EIT window.

[0051] In addition, the two clear mode resonators of the petal-structured ultra-high-sensitivity terahertz antibiotic sensor provided in this scheme produce strong interaction under the incidence of electromagnetic waves, forming two sharp transmission valleys and a sharp narrow-band transmission window between the two valleys with a peak frequency of 1.0 THz, so it can be used for the specific detection of chloramphenicol.

[0052] Specifically, the two petal-structured resonators can each generate clear-mode resonance (a high-radiative loss state) under the excitation of electromagnetic waves. When the two resonators are close to each other, the electric fields formed by the two resonators overlap in the gap region, forming near-field coupling. At the same time, through the interaction of electromagnetic fields with opposite phases, the radiation loss is offset, forming a low-damped transparent state (EIT window). A single resonator corresponds to the ground state (loss state). After the dual resonators are coupled, the sensor can transition from the ground state to the transparent state (low-loss state). This process is achieved through resonant frequency detuning (0.99 THz and 1.02 THz) and phase interference, ultimately generating a sharp transmission peak at 1.0 THz.

[0053] Furthermore, because the petal-structured ultra-high-sensitivity terahertz antibiotic sensor provided by this solution utilizes a graphene layer, the peak frequency can be red-shifted by adjusting the graphene's Fermi level. In other words, when the structure is fixed and the graphene's Fermi level is 0.3 eV, the peak frequency is fixed at 1.0 THz. However, by adjusting the Fermi level (0.3–0.7 eV), the peak frequency can be red-shifted, achieving frequency modulation within the range of 0.51–1.0 THz. However, the optimal sensing performance remains concentrated near 1.0 THz, allowing the detection of different characteristic peaks through adjustment of different Fermi levels.

[0054] In other words, the petal-structured ultra-high-sensitivity terahertz antibiotic sensor of this scheme can achieve frequency modulation within 0.51–1.0 THz, and when modulated to a peak at 1.0 THz, it can be used to detect chlortetracycline.

[0055] In some embodiments, the petal-structure-based ultra-high-sensitivity terahertz antibiotic sensor includes a plurality of sensing units arranged in an array, such as Figure 2 As shown, Figure 2 The petal-structured ultra-high-sensitivity terahertz antibiotic sensor in the paper includes 8*6 sensing units.

[0056] Example 2

[0057] In order to study and verify the performance of the petal-structured ultra-high-sensitivity terahertz antibiotic sensor designed in this scheme, a simulated environment was set up for performance testing:

[0058] The simulation environment is as follows: CST Microwave Studio finite element method software is used to perform electromagnetic simulation in the 0.3-1.2THz frequency band. The Fermi level of graphene is controlled by externally adjusting the bias voltage between the metal gate and the quartz substrate. The electromagnetic wave is a plane wave incident vertically in the -z direction. The boundary conditions are set to single units in the x and y directions and open in the z direction. The ambient temperature is 300K.

[0059] Parameter design of ultra-high sensitivity terahertz antibiotic sensor based on petal structure:

[0060] The maximum distance R2 from the curved section on the outer ring of the resonator in each sensing unit to the center of the outer ring is 17 μm, and the minimum distance r2 from the curved section on the outer ring to the center of the outer ring is 11 μm; the maximum distance R1 from the curved section on the inner ring to the center of the inner ring is 7.5 μm, and the minimum distance r1 from the curved section on the inner ring to the center of the inner ring is 4.8 μm; the side length Px of the dielectric plate along the x direction and the side length Py along the y direction are 72 μm, the resonant pattern width w is 2 μm, the thickness of the dielectric plate is d, the thickness of the graphene layer is 0.001 μm, the resonant distance is s, and the thickness of the dielectric layer is d.

[0061] (1) Simulation design of EIT effect:

[0062] To investigate the physical mechanism of the petal-based ultra-high-sensitivity terahertz antibiotic sensor, the dielectric layer thickness d was set to 10 μm and the resonance distance s was set to 2.95 μm. The present invention performed simulations using the frequency-domain finite-difference method. The simulations were divided into three cases: (i) only the upper right petal-shaped graphene resonant ring, (ii) only the lower left petal-shaped graphene resonant ring, and (iii) the complete structure. The simulation results are shown in Figure 2. Figure 3 and Figure 4 As shown, Figure 3 This is a schematic diagram of the EIT mechanism analysis of the petal-structured ultra-high-sensitivity terahertz antibiotic sensor designed by the present invention. By comparing the transmission spectra of three simulation cases (i), (ii), and (iii), the mechanism of the EIT window formed by dual-resonator coupling (a narrow-band transparent window appears between the two transmission valleys) is demonstrated. Figure 4 This is the electric field diagram at the resonant frequency of the petal-based ultrahigh-sensitivity terahertz antibiotic sensor designed in this invention. Simulation results show that (iii) the two clear-mode resonators in the complete structure strongly interact under electromagnetic wave incidence, forming two sharp transmission valleys and a sharp, narrowband transmission window between them, with a peak frequency of 1.0 THz.

[0063] Specifically, from the perspective of the EIT window mechanism, the present invention forms a sharp EIT window at 1.0 THz through the near-field coupling of two clear mode resonators. The formation mechanism of the EIT window is based on the quantum interference effect. The electromagnetic transmission between the two resonators is coupled to a low-damping mode with an opposite phase, restoring the resonance and offsetting the loss, thereby generating a narrowband transparent window in the absorption spectrum. This EIT effect not only improves the sensitivity of the sensor, but also enhances the dispersion characteristics, making it suitable for high-precision sensing applications. The generation of the EIT effect enables the sensor to achieve high transmittance at a specific frequency while enhancing the dispersion characteristics. The formation of this EIT window is achieved through the design of a petal structure. Compared with the traditional circular ring structure, the petal-shaped resonator can concentrate energy at the concave point of the petal, significantly enhancing the electric field strength, thereby generating a strong near-field coupling effect.

[0064] (2) The effect of the thickness d of the dielectric layer on the transparent window

[0065] By setting the thickness d of the dielectric layer to 5μm, 7μm, 10μm and 12μm respectively, and the resonance distance s to 2.95μm, the transparent window of the ultra-high sensitivity terahertz antibiotic sensor based on the petal structure was simulated and tested, and the results were shown in the figure. Figure 6 As shown in the figure, it can be seen that with the increase of the thickness d of the dielectric layer, the window peak redshifts, the window bandwidth decreases, and the transmittance decreases slightly. This is because the increase in the thickness of the dielectric layer provides space for the incident electromagnetic wave to undergo multiple reflections and interferences in the metamaterial structure, resulting in a mutually offset effect, and ultimately producing a transparent window with a narrower linewidth.

[0066] (3) Influence of coupling distance on transparent window

[0067] By setting the coupling distance s to 2.95μm, 5.7μm, 7.1μm, 8.4μm, and 9.6μm, the transparent window of the ultra-high sensitivity terahertz antibiotic sensor based on the petal structure was simulated and tested, and the results were shown in the figure. Figure 7 As shown, it can be seen that as the coupling distance s increases, the coupling effect between the two clear mode resonators is weakened, thereby reducing the transmittance of the window. The performance is optimal when the coupling distance s is 2.95μm.

[0068] (4) Fermi level control

[0069] By adjusting the Fermi level of graphene to 0.3eV, 0.4eV, 0.5eV, 0.6eV and 0.7eV, and conducting simulation tests on the transparent window of the ultra-high sensitivity terahertz antibiotic sensor based on the petal structure, the transmission curve generated by the Fermi level change is obtained as shown in the figure. Figure 8 As shown, the window frequency diagram corresponding to different Fermi levels is as follows Figure 9 As shown, it can be seen that the present invention realizes the dynamic regulation of the sensor. The Fermi level of graphene can be adjusted by an external bias voltage, thereby controlling the surface conductivity of the sensor and realizing the dynamic switching of the EIT window; when the Fermi level is 0.3eV, the transparent window is in the "on" state; when the Fermi level increases to 0.7eV, the EIT window is destroyed and the transparent window is in the "off" state.

[0070] According to the definition of frequency modulation depth MD, the maximum modulation depth that can be achieved by this petal-structured ultra-high-sensitivity terahertz antibiotic sensor is 43%, and the picosecond response time of the graphene material can quickly complete optical modulation.

[0071] (5) Polarization insensitivity test:

[0072] The thickness of the dielectric layer d is set to 10 μm, the resonance distance s is set to 2.95 μm, and the polarization test results of the ultra-high sensitivity terahertz antibiotic sensor based on the petal structure are obtained in different directions. Figure 5 As shown, the visible sensor exhibits the same transmission curve under the x-polarization and y-polarization directions, indicating that it has polarization-insensitive characteristics. This characteristic enables the sensor to work stably in complex environments and is suitable for a variety of application scenarios. Traditional EIT sensors often exhibit different sensing performance under different polarization directions, which limits their application in complex environments. The present invention achieves polarization-insensitive characteristics through the design of a petal structure, so that the sensor exhibits stable sensing performance under both vertical and horizontal polarization conditions. The sensitivity is as high as 1.225 THz / RIU, and the Q value is 20.8. Compared with the prior art, the sensor designed in the present invention has high sensitivity and a Q value that reaches a high level, which significantly improves the sensing performance.

[0073] (6) Tests of different refractive indices:

[0074] The thickness d of the dielectric layer is set to 10 μm, the resonance distance s is set to 2.95 μm, and polarization tests are performed on samples with refractive indices of 1.0, 1.1, 1.2, 1.3, and 1.4 in different directions. The transmission curves corresponding to different refractive indices under x polarization of the ultra-high sensitivity terahertz antibiotic sensor based on the petal structure are shown in the figure below. Figure 10 As shown in the figure, the window frequency diagram of the ultra-high sensitivity terahertz antibiotic sensor based on the petal structure under different refractive indices under x polarization is shown in Figure 11 As shown, the corresponding transmission curves under different refractive indices under y polarization are as follows Figure 12 As shown, the window frequency diagram corresponding to different refractive indices under y polarization is as follows Figure 13 shown.

[0075] Figure 10 is the transmission spectrum corresponding to different refractive indices (n=1.0–1.4) in the x-polarization direction, Figure 10 As can be seen, as the refractive index increases, the EIT window frequency redshifts from 1.0 THz to 0.51 THz, verifying the sensor's sensitivity to refractive index changes. Slope calculation yields a sensitivity of 1.225 THz / RIU.

[0076] Figure 11 is the linear relationship between window frequency and refractive index under x polarization, Figure 11 It can be seen that when the frequency changes linearly with the refractive index, the linear response characteristics and high sensitivity of the sensor are demonstrated. Figure 12 is the transmission spectrum corresponding to different refractive indices in the y polarization direction, Figure 12 It can be seen that, similar to the x-polarization, the window frequency shifts from 1.0 THz to 0.53 THz, verifying the stability of the sensor under different polarization directions. The calculated sensitivity result is close to 1.225 THz / RIU, indicating polarization insensitivity. Figure 13 is the linear relationship between window frequency and refractive index under y polarization, Figure 13 It can be seen that the results are consistent with the x-polarization results, further proving the polarization independence and reliability of the sensor.

[0077] In summary, the petal-structured ultra-high-sensitivity terahertz antibiotic sensor provided by this solution can achieve a balance between high sensitivity and high Q value, significantly enhancing the sensitivity of the sensor while maintaining a high Q value, solving the problem of insufficient detection accuracy of traditional EIT sensors under high-sensitivity conditions; it can have dynamic adjustability: by adjusting the Fermi level of graphene, dynamic regulation of the sensor is achieved, and the maximum modulation depth can reach 43%; it can have polarization-insensitive characteristics: the sensor exhibits stable sensing performance under different polarization directions, and is suitable for applications in complex environments.

[0078] Those skilled in the art should understand that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0079] The above embodiments merely illustrate several embodiments of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. An ultra-high sensitivity terahertz antibiotic sensor based on a petal structure, characterized in that: include: At least one array of sensor units; Each sensing unit includes a graphene layer and a dielectric layer from top to bottom, wherein two identical resonators are formed on the graphene layer, and each resonator is designed as a petal structure including an inner ring and an outer ring. The centers of the inner ring and the outer ring in each resonator overlap and are spaced apart, and the inner ring and the outer ring have the same shape. The inner ring is a closed loop formed by at least two curved segments connected end to end, and the curvature of each curved segment is the same, and adjacent curved segments are connected to form a concave point on the inner ring; the outer ring is also a closed loop formed by at least two curved segments connected end to end, and the curvature of each curved segment is the same, and adjacent curved segments are connected to form a concave point on the outer ring; each curved segment on the inner ring is a circular arc segment convex outward relative to the center of the inner ring, and the arc center of the curved segment does not overlap with the center of the inner ring; each curved segment on the outer ring is a circular arc segment convex outward relative to the center of the outer ring, and the arc center of the curved segment does not overlap with the center of the outer ring, and each curved segment of the inner ring corresponds one-to-one to each curved segment of the outer ring; The two resonator structures are staggered, and the line connecting the resonance centers of the two resonators is tilted compared to the dielectric layer. The coupling distance s between the two resonators is 2~5μm. The two petal-structured resonators can respectively generate bright mode resonance under the excitation of electromagnetic waves. When the two resonators are close to each other, the electric fields formed by the two resonators overlap in the gap area, forming near-field coupling. At the same time, through the interaction of electromagnetic fields with opposite phases, the radiation loss is offset to form a low-damping transparent state. Frequency modulation can be achieved within 0.51-1.0 THz. When modulated to a peak at 1.0 THz, it can be used to detect chloramphenicol.

2. The petal-structure-based ultra-high-sensitivity terahertz antibiotic sensor according to claim 1, characterized in that: The maximum distance R2 from the curved section on the outer ring to the center of the outer ring on the same resonator is 17 μm, the minimum distance r2 from the curved section on the outer ring to the center of the outer ring is 11 μm, the maximum distance R1 from the curved section on the inner ring to the center of the inner ring is 7.5 μm, and the minimum distance r1 from the curved section on the inner ring to the center of the inner ring is 4.8 μm.

3. The petal-structure-based ultra-high-sensitivity terahertz antibiotic sensor according to claim 1, characterized in that: The dielectric layer is a quartz dielectric plate made of quartz material. The relative dielectric constant of the quartz dielectric plate is 1.9, and the thickness d of the dielectric layer is 5 to 12 μm.

4. The petal-structure-based ultra-high-sensitivity terahertz antibiotic sensor according to claim 1, characterized in that: The shortest distance between two resonators is 2 μm.

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