A terahertz metasurface sensor and system for identifying lactic acid enantiomers

Abstract

The application discloses a terahertz metasurface sensor and system for identifying lactic acid enantiomers, which comprises an insulating substrate with uniform material thickness, and a plurality of metal microstructures arranged periodically in a two-dimensional array on the surface of the insulating substrate; the metal microstructure comprises a first metal component and a second metal component; the first metal component comprises a first metal trunk and a plurality of first metal strip components arranged on the first metal trunk; the second metal component comprises a second metal trunk and a second metal strip component arranged at each end of the second metal trunk respectively, and the second metal trunk and the second metal strip component form a rectangular open ring; the first metal component is arranged on one side of the opening of the second metal component and extends to the opening of the second metal component without touching. The application has the advantages of simple structure, low preparation cost, no need of additional additives and reaction for lactic acid detection, and realization of rapid and label-free identification of different types of lactic acid enantiomers.

Description

Technical Field

[0001] This application relates to the field of lactic acid enantiomer detection technology, and more specifically, to a terahertz metasurface sensor and system for identifying lactic acid enantiomers. Background Technology

[0002] Chiral molecules are molecules or structures that do not have mirror-image properties. Chiral molecules (called chiral enantiomers) exist as enantiomers; they have almost identical physical properties but differ significantly in biological and chemical properties and physiological activities, making them a key consideration in drug development. Lactic acid (2-hydroxypropionic acid) is a naturally occurring organic acid widely found in humans, animals, plants, and microorganisms. Due to an asymmetric carbon atom in its molecule, it exhibits optical isomerism. Lactic acid molecules have chiral enantiomers in the L and D configurations; L-lactic acid is levorotatory, and D-lactic acid is dextrorotatory. Mixing L-lactic acid and D-lactic acid in equal proportions forms racemic DL-lactic acid.

[0003] Currently, the main methods for detecting lactic acid include: (1) enzymatic hydrolysis (based on carbon-microelectromechanical systems (IEEE Sensors Journal, 2020, 20(16): 8965-8972.), nanoparticle colorimetric method (Microchim Acta, 2019 186, 121.), or based on functional graphene sheets with lactate dehydrogenase (Sensors 2021, 21(5): 1852.); (2) nanocluster method (Journal of Electroanalytical Chemistry, 874, 1, 2020, 114465.). The separation and identification of L-lactic acid and D-lactic acid mainly employ high-performance liquid chromatography-tandem mass spectrometry, pre-column fluorescence derivatization column-changing high-performance liquid chromatography (Anal Bioanal Chem, 2003, 377, 886-891.), and chiral derivatization gas chromatography-mass spectrometry (Journal of Separation). Science, 2018, 41(12):2576-2584. However, due to the influence of the fluorescent agent's lifetime and the need to add additional additives, the above method has certain limitations in practical applications. Summary of the Invention

[0004] In view of this, this application provides a terahertz metasurface sensor and system for identifying lactic acid enantiomers, in order to solve at least one of the aforementioned technical problems.

[0005] To achieve the above objectives, the first aspect of this application provides a terahertz metasurface sensor for identifying lactic acid enantiomers, comprising an insulating substrate with uniform material thickness and a plurality of metal microstructures arranged periodically on the surface of the insulating substrate in the form of a two-dimensional array.

[0006] The material thickness of the metal microstructure is less than the material thickness of the insulating substrate;

[0007] The metal microstructure includes a first metal component and a second metal component;

[0008] The first metal component includes a first metal backbone and a plurality of first metal strip components disposed on the first metal backbone, wherein the plurality of first metal strip components are disposed on the same side of the first metal backbone;

[0009] The second metal component includes a second metal trunk and second metal strip components respectively disposed at both ends of the second metal trunk, wherein the second metal trunk and the second metal strip components form a rectangular open ring.

[0010] The first metal component is disposed on the opening side of the second metal component, the first metal strip component extends toward the opening of the second metal component, and the first metal component and the second metal component do not touch.

[0011] Preferably, the insulating substrate is made of polyimide, silicon dioxide, or silicon.

[0012] Preferably, the thickness of the insulating substrate is in the range of [3μm, 1000μm].

[0013] Preferably, the dielectric constant of the insulating substrate is in the range of [2, 6].

[0014] Preferably, the material thickness of the metal microstructure is in the range of [0.05μm, 5μm].

[0015] Preferably, the material of the metal microstructure is gold, silver, copper, or aluminum.

[0016] Preferably, the period length of the two-dimensional array is in the range of [200μm, 500μm] in both the horizontal and vertical directions;

[0017] The two-dimensional array has more than 10 elements in the horizontal direction and more than 10 elements in the vertical direction.

[0018] Preferably, the length of the first metal backbone is 170 μm; the length of the first metal strip component is 75 μm; the number of the first metal strip components is 2, the distance from the first metal strip component to the center of the first metal backbone is equal, and the distance between the two first metal strips is 64 μm;

[0019] The length of the second metal backbone is 270 μm; the length of the second metal strip component is 60 μm;

[0020] The material width of the first metal backbone is 35 μm; the material width of the first metal strip component is 30 μm;

[0021] The width of both the second metal backbone and the second metal strip component is 50 μm;

[0022] Both the first metal component and the second metal component are made of gold; the thickness of both the first metal component and the second metal component is 0.2 μm.

[0023] The insulating substrate is made of polyimide, has a thickness of 30 μm, a dielectric constant of 3.4, and a loss tangent of 0.002.

[0024] The two-dimensional array has a period length of 340 μm in both the horizontal and vertical directions.

[0025] A second aspect of this application provides a system for identifying lactic acid enantiomers, including a terahertz time-domain spectroscopy testing device and a terahertz metasurface sensor as described above.

[0026] The terahertz time-domain spectroscopy testing device is used to generate and receive terahertz electromagnetic waves and acquire the transmission spectrum data of the terahertz metasurface sensor. The transmission spectrum data is used to determine the type of lactic acid enantiomer to be identified.

[0027] The terahertz metasurface sensor is used to place the lactic acid enantiomer to be identified and to receive the radiation of the terahertz electromagnetic wave to generate transmission spectrum data. The types of lactic acid enantiomers include D-type lactic acid, L-type lactic acid and DL-type lactic acid.

[0028] Preferably, the process of measuring the transmission spectrum data generated by the terahertz metasurface sensor and using the transmission spectrum data to determine the type of lactic acid enantiomer to be identified includes:

[0029] For each lactate enantiomer to be identified:

[0030] The terahertz metasurface sensor was cleaned with anhydrous ethanol and deionized water to obtain the cleaned terahertz metasurface sensor.

[0031] The terahertz metasurface sensor was dried and cleaned using nitrogen gas to obtain the dried terahertz metasurface sensor.

[0032] The lactic acid enantiomers to be identified at a preset concentration and a preset dose are placed on the dried terahertz metasurface sensor.

[0033] After the lactic acid enantiomer to be identified is dried, the terahertz metasurface sensor is irradiated using the terahertz time-domain spectroscopy testing device, and the transmission spectrum data of the terahertz metasurface sensor is obtained.

[0034] Based on the transmission spectrum data of the lactic acid enantiomer to be identified, the transmission spectrum shift of the lactic acid enantiomer to be identified is determined.

[0035] The lactic acid enantiomer with the largest transmission spectrum shift was identified as L-type lactic acid, and the lactic acid enantiomer with the smallest transmission spectrum shift was identified as D-type lactic acid.

[0036] As described above, the terahertz metasurface sensor for identifying lactic acid enantiomers provided in this application includes an insulating substrate with uniform material thickness and multiple metal microstructures periodically arranged in a two-dimensional array on the surface of the insulating substrate, forming a metasurface structure on the surface of the insulating substrate. The material thickness of the metal microstructures is less than the material thickness of the insulating substrate. Each metal microstructure includes a first metal component and a second metal component. The first metal component includes a first metal trunk and multiple first metal strip components disposed on the first metal trunk, with the multiple first metal strip components disposed on the same side of the first metal trunk. The second metal component includes a second metal trunk and second metal strip components respectively disposed at both ends of the second metal trunk, forming a rectangular open annular shape. The first metal component is disposed on one side of the opening of the second metal component, and the first metal strip components extend towards the opening of the second metal component, without contacting each other. Compared to an unloaded terahertz metasurface sensor, a terahertz metasurface sensor loaded with lactic acid enantiomers can cause a redshift in the terahertz transmission spectrum. Furthermore, when different types of lactic acid enantiomers are loaded onto the surface of the terahertz metasurface sensor, transmission spectra with different offsets can be generated, thereby allowing identification of the specific type of the loaded lactic acid enantiomer. This application combines terahertz electromagnetic waves and a terahertz metasurface sensor to identify different types of lactic acid enantiomers. The terahertz metasurface sensor has a simple structure, low manufacturing cost, and does not require additional additives or reactions, enabling label-free, real-time monitoring. As a highly sensitive detection component for biological chiral structures, it has excellent application prospects. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] Figure 1 This application illustrates a terahertz metasurface sensor for identifying lactic acid enantiomers, as disclosed in an embodiment of the present application.

[0039] Figure 2 The metal microstructure in the terahertz metasurface sensor disclosed in the embodiments of this application is illustrated;

[0040] Figure 3 The period length of the two-dimensional array of terahertz metasurface sensors disclosed in the embodiments of this application is illustrated.

[0041] Figure 4 The dimensions of the metallic microstructures disclosed in embodiments of this application are illustrated;

[0042] Figure 5 The system for identifying lactate enantiomers disclosed in embodiments of this application is illustrated;

[0043] Figure 6 An example of a terahertz metasurface sensor with lactic acid enantiomers disposed thereon is provided in an embodiment of this application;

[0044] Figure 7 The example illustrates the test results of the terahertz metasurface sensor disclosed in this application for identifying the transmission spectrum of lactic acid. Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] The following describes a terahertz metasurface sensor for identifying lactic acid enantiomers provided in an embodiment of this application. Please refer to... Figure 1 The terahertz metasurface sensor for identifying lactic acid enantiomers provided in this application embodiment may include an insulating substrate 10 with uniform material thickness and a plurality of metal microstructures 20 arranged periodically on the surface of the insulating substrate 10 in the form of a two-dimensional array.

[0047] The material thickness of the metal microstructure 20 is less than the material thickness of the insulating substrate 10.

[0048] Please see Figure 2 The metal microstructure 20 includes a first metal component 21 and a second metal component 22.

[0049] The first metal component 21 includes a first metal backbone 211 and a plurality of first metal strip components 212 disposed on the first metal backbone 211, wherein these first metal strip components 212 are disposed on the same side of the first metal backbone 211.

[0050] The second metal component 22 includes a second metal trunk 221 and second metal strip components 222 respectively disposed at both ends of the second metal trunk 221, wherein the second metal trunk 221 and the second metal strip components 222 form a rectangular open ring.

[0051] The first metal component 21 is disposed on the opening side of the second metal component 22, the first metal strip component 212 extends toward the opening of the second metal component 22, and the first metal component 21 and the second metal component 22 do not touch.

[0052] This application provides a terahertz metasurface sensor for identifying lactic acid enantiomers, comprising an insulating substrate with uniform material thickness and a plurality of metal microstructures periodically arranged in a two-dimensional array on the surface of the insulating substrate, thereby forming a metasurface structure on the surface of the insulating substrate. The material thickness of the metal microstructures is less than the material thickness of the insulating substrate; each metal microstructure includes a first metal component and a second metal component; the first metal component includes a first metal trunk and a plurality of first metal strip components disposed on the first metal trunk, the plurality of first metal strip components being disposed on the same side of the first metal trunk; the second metal component includes a second metal trunk and second metal strip components respectively disposed at both ends of the second metal trunk, the second metal trunk and the second metal strip components forming a rectangular open annular shape; the first metal component is disposed on one side of the opening of the second metal component, the first metal strip components extend towards the opening of the second metal component, and the first metal component and the second metal component do not touch. Compared with an unloaded terahertz metasurface sensor, a terahertz metasurface sensor loaded with lactic acid enantiomers can cause a redshift in the terahertz transmission spectrum. Furthermore, when different types of lactic acid enantiomers are loaded onto the surface of the terahertz metasurface sensor, transmission spectra with different offsets can be generated, thereby allowing identification of the specific type of the loaded lactic acid enantiomer. This application combines terahertz electromagnetic waves and a terahertz metasurface sensor to identify different types of lactic acid enantiomers. The terahertz metasurface sensor has a simple structure, low manufacturing cost, and does not require additional additives or reactions, enabling label-free, real-time monitoring. As a highly sensitive detection component for biological chiral structures, it has excellent application prospects.

[0053] In some embodiments of this application, the material of the insulating substrate 10 can be polyimide, silicon dioxide, or silicon, etc. Specifically, materials such as polyimide, silicon dioxide, or silicon with different dielectric constants and dielectric losses can be selected.

[0054] In some embodiments of this application, the material thickness of the insulating substrate 10 ranges from [3 μm to 1000 μm]. Exemplarily, this material thickness can be 20 μm, 50 μm, 200 μm, etc. The dielectric constant of the insulating substrate 10 ranges from [2 to 6]. Exemplarily, this dielectric constant can be 3.4, 4.41, etc. A suitable dielectric material is selected based on the specific operating frequency band required by the design.

[0055] In some embodiments of this application, the material thickness of the metal microstructure 20 ranges from [0.05 μm to 5 μm]. It should be noted that the material thickness of the metal microstructure 20 must be less than the material thickness of the insulating substrate 10. For example, the metal microstructure 20 can be etched on a gold film with a material thickness of 200 nm.

[0056] In some embodiments of this application, the material of the metal microstructure 20 is gold, silver, copper or aluminum.

[0057] In some embodiments of this application, such as Figure 3 As shown, the periodic length of the two-dimensional array ranges from [200μm, 500μm] in both the horizontal and vertical directions. Assuming the number of elements in the horizontal direction of the two-dimensional array is m, and the number of elements in the vertical direction is n, then m×n periodic units can be formed on the insulating substrate 10, where m≥10, n≥10 (…). Figure 3 Due to space limitations, only the case of 3×3 periodic units is illustrated. It is understandable that if the insulating substrate 10 is not a rectangular structure, but rather another polygonal form, the number of periods can be represented in other ways.

[0058] In some embodiments of this application, please refer to Figure 4 The length of the first metal backbone 211 is L1 = 170 μm; the length of the first metal strip component 212 is L2 = 75 μm; there are 2 first metal strip components 212, the distance from the first metal strip component 212 to the center of the first metal backbone 211 is equal, and the distance between the two first metal strips is L3 = 64 μm.

[0059] The length of the second metal main body 221 is L4 = 270 μm; the length of the second metal strip component 222 is L5 = 60 μm.

[0060] The material width of the first metal backbone 211 is w1 = 35 μm; the material width of the first metal strip component 212 is w2 = 30 μm.

[0061] The material width of both the second metal main body 221 and the second metal strip component 222 is w3 = 50δm.

[0062] Both the first metal component 21 and the second metal component 22 are made of gold; the thickness of both the first metal component 21 and the second metal component 22 is 0.2 μm.

[0063] The material, thickness, dielectric constant, and loss tangent of the insulating substrate 10 are polyimide, 30 μm, 3.4, and 0.002, respectively.

[0064] The period length of the two-dimensional array is T = 340 μm in both the horizontal and vertical directions.

[0065] The following describes a technical solution for identifying different types of lactic acid enantiomers using the terahertz metasurface sensor provided in the above embodiments. To introduce this technical solution, the entire system architecture will be described first.

[0066] Please see Figure 5 The system for identifying lactic acid enantiomers provided in this application embodiment may include a terahertz time-domain spectroscopy testing device and the terahertz metasurface sensor provided in the above embodiments.

[0067] The terahertz time-domain spectroscopy testing device is used to generate and receive terahertz electromagnetic waves and acquire the transmission spectrum data of the terahertz metasurface sensor; the terahertz metasurface sensor is used to place the lactic acid enantiomer to be identified and to receive the radiation of the terahertz electromagnetic waves to generate transmission spectrum data.

[0068] The types of lactate enantiomers include D-type lactate, L-type lactate, and DL-type lactate; the above transmission spectral data are used to determine the type of lactate enantiomer to be identified.

[0069] In some embodiments of this application, the process of acquiring transmission spectrum data generated by the terahertz metasurface sensor and using the transmission spectrum data to determine the type of lactic acid enantiomer to be identified may include:

[0070] Step S100, for each lactate enantiomer to be identified:

[0071] S110, the terahertz metasurface sensor is cleaned using anhydrous ethanol and deionized water to obtain the cleaned terahertz metasurface sensor.

[0072] S120, using nitrogen to dry and clean the terahertz metasurface sensor, to obtain the dried terahertz metasurface sensor.

[0073] For the dried terahertz metasurface sensor, the transmission spectrum when it is empty (without any material) can be measured by this system to verify that it has indeed been cleaned and dried.

[0074] S130, place the lactic acid enantiomer to be identified at a preset concentration and dose on the dried terahertz metasurface sensor.

[0075] For example, the preset dose can be 10 μL of lactate enantiomer, which can be obtained using a pipette, such as... Figure 6 As shown, the lactic acid enantiomer is placed on the upper surface of the terahertz metasurface sensor. The preset concentration can be any concentration above 0.1 μg / mL, but the concentration of each lactic acid enantiomer to be identified must be consistent; that is, the concentrations of L-lactic acid, D-lactic acid, and LD-lactic acid to be identified must be the same.

[0076] S140, after the lactic acid enantiomer to be identified is dried, the terahertz metasurface sensor is irradiated using the terahertz time-domain spectroscopy testing device, and the transmission spectrum data of the terahertz metasurface sensor is acquired.

[0077] In particular, when terahertz electromagnetic waves in the terahertz time-domain spectrum testing device are incident perpendicularly on the surface of the terahertz metasurface sensor, a better radiation effect can be produced.

[0078] S150, based on the transmission spectrum data of the lactic acid enantiomer to be identified, determine the transmission spectrum shift of the lactic acid enantiomer to be identified.

[0079] By performing the above steps S110 to S150 on each lactic acid enantiomer (L-lactic acid, D-lactic acid, and LD-lactic acid) with the same concentration and dosage, the transmission spectrum shift of each lactic acid enantiomer can be obtained.

[0080] Different concentrations of L-type lactic acid, D-type lactic acid, and DL-type lactic acid can be obtained through stepwise dilution. The methods for obtaining D-type lactic acid solutions and DL-type lactic acid solutions of different concentrations are the same as those for preparing L-type lactic acid solutions.

[0081] In step S200, the lactic acid enantiomer with the largest transmission spectrum shift is identified as L-type lactic acid, and the lactic acid enantiomer with the smallest transmission spectrum shift is identified as D-type lactic acid.

[0082] Lactic acid enantiomers, as chiral media, are typically characterized by the chiral parameter κ to describe the cross-coupling strength of electromagnetic fields. The boundary conditions of chiral media are described as follows:

[0083]

[0084] In the formula, ε0 and μ0 are the electrical conductivity and magnetic permeability in vacuum, respectively; ε and μ are the relative electrical conductivity and magnetic permeability of the chiral medium, respectively; c0 is the speed of light in vacuum; i represents the imaginary number; D is the electric displacement vector; B is the magnetic induction intensity; E is the electric field intensity; and H is the magnetic field intensity.

[0085] In the terahertz band, the chiral parameters of chiral medium molecules are described as follows:

[0086]

[0087] Wherein, the coefficient β is the chiral molecular density, h is the reduced Planck constant ω0=2πc / λ0, λ0 is the molecular vibration wavelength, and Γ is the resonance broadening.

[0088] Please see Figure 7The study presents the transmission spectrum changes of a terahertz metasurface sensor after loading 10 μL of L-type lactic acid, D-type lactic acid, DL-type lactic acid, and in its unloaded state (without any lactic acid enantiomer). Compared to the unloaded terahertz metasurface sensor, the transmission spectrum exhibits a redshift after loading lactic acid. Specifically, the midpoint of the transmission spectrum in the unloaded state is at 0.3174 THz; after loading L-type lactic acid, the midpoint is at 0.3161 THz; after loading DL-type lactic acid, the midpoint is at 0.3163 THz; and after loading D-type lactic acid, the midpoint is at 0.3169 THz. It is evident that loading lactic acid causes a redshift in the transmission spectrum of the terahertz metasurface, with the largest shift observed in L-type lactic acid, followed by DL-type lactic acid, and the smallest shift observed in D-type lactic acid. Chiral lactic acid of different concentrations can be detected by measuring the transmission spectrum changes of a terahertz metasurface sensor, with a detection limit as low as 0.1 μg / mL.

[0089] In summary:

[0090] This application provides a terahertz metasurface sensor for identifying lactic acid enantiomers, comprising an insulating substrate with uniform material thickness and a plurality of metal microstructures periodically arranged in a two-dimensional array on the surface of the insulating substrate, thereby forming a metasurface structure on the surface of the insulating substrate. The material thickness of the metal microstructures is less than the material thickness of the insulating substrate; each metal microstructure includes a first metal component and a second metal component; the first metal component includes a first metal trunk and a plurality of first metal strip components disposed on the first metal trunk, the plurality of first metal strip components being disposed on the same side of the first metal trunk; the second metal component includes a second metal trunk and second metal strip components respectively disposed at both ends of the second metal trunk, the second metal trunk and the second metal strip components forming a rectangular open annular shape; the first metal component is disposed on one side of the opening of the second metal component, the first metal strip components extend towards the opening of the second metal component, and the first metal component and the second metal component do not touch. Compared with an unloaded terahertz metasurface sensor, a terahertz metasurface sensor loaded with lactic acid enantiomers can cause a redshift in the terahertz transmission spectrum. Furthermore, when different types of lactic acid enantiomers are loaded onto the surface of the terahertz metasurface sensor, transmission spectra with different offsets can be generated, thereby allowing identification of the specific type of the loaded lactic acid enantiomer. This application combines terahertz electromagnetic waves and a terahertz metasurface sensor to identify different types of lactic acid enantiomers. The terahertz metasurface sensor has a simple structure, low manufacturing cost, and does not require additional additives or reactions, enabling label-free, real-time monitoring. As a highly sensitive detection component for biological chiral structures, it has excellent application prospects.

[0091] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0092] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0093] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A terahertz metasurface sensor for identifying lactic acid enantiomers, characterized by, The insulating substrate includes a uniform material thickness, and a plurality of metal microstructures arranged periodically in a two-dimensional array on the surface of the insulating substrate; The material thickness of the metal microstructure is less than the material thickness of the insulating substrate; The metal microstructure includes a first metal component and a second metal component; The first metal component includes a first metal stem and a plurality of first metal strip components arranged on the same side of the first metal stem; The second metal component includes a second metal stem and a second metal strip component arranged at both ends of the second metal stem respectively, and the second metal stem and the second metal strip component form a rectangular open ring; The first metal component is arranged on one side of the opening of the second metal component, the first metal strip component extends to the opening of the second metal component, and the first metal component and the second metal component do not touch each other; wherein the length of the second metal stem is 270 μm; the length of the second metal strip component is 60 μm; the length of the first metal strip component is 75 μm; the number of the first metal strip components is 2, and the distance from the two first metal strip components to the center of the first metal stem is equal.

2. The terahertz metasurface sensor of claim 1, wherein, The material of the insulating substrate is polyimide, silicon dioxide or silicon.

3. The terahertz metasurface sensor of claim 1, wherein, The material thickness of the insulating substrate ranges from 0.1 to 1 mm .

4. The terahertz metasurface sensor of claim 1, wherein, The dielectric constant value of the insulating substrate ranges from 2.5 to 3.5 .

5. The terahertz metasurface sensor of claim 1, wherein, The material thickness of the metal microstructure ranges from .

6. The terahertz metasurface sensor of claim 1, wherein, The material of the metal microstructure is gold, silver, copper or aluminum.

7. The terahertz metasurface sensor of claim 1, wherein, The period length of the two-dimensional array in the lateral direction and in the longitudinal direction each ranges from ; The number of elements in the two-dimensional array in the transverse direction is more than 10, and the number of elements in the two-dimensional array in the longitudinal direction is more than 10.

8. The terahertz metasurface sensor of claim 1, wherein, The length of the first metal stem is 170 μm; the distance between the two first metal strips is 64 μm; The material width of the first metal stem is 35 μm; the material width of the first metal strip component is 30 μm; The material width of the second metal stem and the second metal strip component is 50 μm; The materials of the first metal component and the second metal component are both gold; the material thickness of the first metal component and the second metal component is both 0.2 μm; The material of the insulating substrate is polyimide, the material thickness of the insulating substrate is 30 μm, the dielectric constant of the insulating substrate is 3.4, and the loss tangent of the insulating substrate is 0.002; The period length of the two-dimensional array in the transverse direction and the period length of the two-dimensional array in the longitudinal direction are both 340 μm.

9. A system for identifying the enantiomer of lactic acid, characterized in that It comprises: A terahertz time-domain spectrum testing device and a terahertz metasurface sensor according to any one of claims 1-8; The terahertz time-domain spectrum testing device is used to generate and receive terahertz electromagnetic waves, and obtain transmission spectrum data of the terahertz metasurface sensor, wherein the transmission spectrum data is used to determine the type of lactate enantiomers to be identified; The terahertz metasurface sensor is used to place the lactate enantiomers to be identified, and receive the radiation of the terahertz electromagnetic waves to generate transmission spectrum data, wherein the type of the lactate enantiomers includes D-lactic acid, L-lactic acid and DL-lactic acid.

10. The system of claim 9, wherein, The process of obtaining the transmission spectrum data generated by the terahertz metasurface sensor and determining the type of the lactate enantiomers to be identified by using the transmission spectrum data comprises: For each lactic acid enantiomer to be identified: clean the terahertz metasurface sensor with anhydrous ethanol and deionized water to obtain a cleaned terahertz metasurface sensor; dry the cleaned terahertz metasurface sensor with nitrogen to obtain a dried terahertz metasurface sensor; place the lactic acid enantiomer to be identified of a preset concentration and a preset dose on the dried terahertz metasurface sensor; after the lactic acid enantiomer to be identified is dried, radiate the terahertz metasurface sensor with the terahertz time-domain spectrum testing device, and obtain transmission spectrum data of the terahertz metasurface sensor; based on the transmission spectrum data of the lactic acid enantiomer to be identified, determine a transmission spectrum offset of the lactic acid enantiomer to be identified; determine the lactic acid enantiomer with the maximum transmission spectrum offset as L-lactic acid, and determine the lactic acid enantiomer with the minimum transmission spectrum offset as D-lactic acid.

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