Non-driven terahertz metamaterial sensor based on capillary micro-channel

Abstract

The invention relates to a non-driven terahertz metamaterial sensor based on a capillary micro-channel, and belongs to the technical field of metamaterial sensors. A metal part of a metamaterial forms a self-suction micro-channel channel, additional processing is not needed, the micro-channel is naturally formed from the structural design, the processing difficulty is basically reduced to zero, and the cost is reduced. The processing difficulty is greatly reduced, and the processing cost is saved; according to the micro-fluidic channel disclosed by the invention, measured liquid is in direct contact, so that the change of an electromagnetic field regulated and controlled by the metamaterial metal structure can directly act on an object to be measured, and the sensitivity of the metamaterial sensor can be exerted to the greatest extent; the micro-fluidic channel disclosed by the invention needs extremely low amount of liquid to be detected, the amount of the liquid is in a mu L magnitude, the micro-fluidic channel can be used for detecting a micro-fluidic solution, meanwhile, the amount of the liquid is small, absorption of the solution, especially an aqueous solution, to terahertz can be reduced, the detection range can be enlarged, and the reliability of a detection result can be enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metamaterial sensor, and particularly relates to a driving-free terahertz metamaterial sensor based on capillary micro flow channel. BACKGROUND

[0002] Terahertz (THz) wave usually refers to electromagnetic radiation with a frequency range of 0.1 THz-10 THz, and has the characteristics of instantaneousness, low photon energy, high permeability and wide band. The terahertz wave has high resolution and can directly or indirectly detect the information of a substance. Metamaterial is an artificial composite material composed of a periodic array of subwavelength structural units, and is usually composed of a metal structure and a substrate material. The metamaterial has good electromagnetic response characteristics in the terahertz wave band. The electromagnetic response of the metamaterial changes with the electromagnetic characteristics of the environment (the substance covering the surface of the metamaterial), which is reflected in the frequency and amplitude changes of the response curve of the metamaterial. The terahertz metamaterial sensor is one of important applications of metamaterials, and has the advantages of no labeling, high sensitivity and rapidness. In addition, the metamaterial sensor has a small demand for analyte and can be used for micro-substance detection. The combination of terahertz detection technology and the narrow linewidth of metamaterials can further improve the resolution of terahertz detection technology and the sensitivity of terahertz technology, and realize the detection of micro changes of the sample to be measured. The sensor based on metamaterials has the characteristics of sensitivity, no labeling, simplicity and rapid detection, and is widely used in biomedical detection and substance specificity detection.

[0003] In the existing metamaterial sensor, the sample to be tested is usually a solid (dry) sample. For a solution sample, especially an aqueous solution sample, there are challenges in measuring the solution and suspension containing water, because water has strong absorption characteristics for terahertz waves. In the existing reports, the commonly used liquid measurement methods are (A) metamaterial sensor with micro flow channel outside the metal surface: an additional micro flow channel is processed on the surface of the metal layer of the metamaterial. This method has high processing difficulty and high cost, and the measured liquid cannot directly contact the metal. The material for constructing the micro flow channel and the SU-8 photoresist covering the surface of the metamaterial have a dielectric constant of 4.8, which reduces the sensitivity of the metamaterial sensor. (B) metamaterial sensor with micro flow channel outside the substrate: a micro flow channel structure is processed on the substrate material side of the metamaterial sensor. This method has smaller processing difficulty and lower cost, but the metal structure of the metamaterial is separated from the micro flow channel by the substrate material, which cannot fully exert the sensitivity of the metamaterial sensor. (C) sensor chip combined with a microcavity and a metamaterial: a liquid cavity capable of containing a liquid of the order of hundreds of microns is attached to the metal of the metamaterial to form a metamaterial sensor chip. This method has low cost and is convenient to process, but the liquid thickness is usually in the order of tens to hundreds of microns, which has large terahertz absorption. The thick liquid reduces the sensitivity of the sensor and has a large demand for the sample to be measured.

[0004] In summary, in the existing metamaterial sensor for measuring liquid (especially aqueous solution), there are disadvantages such as low sensitivity, high processing difficulty, and large amount of sample required, which cannot meet the sensitive measurement requirement of trace aqueous solution. SUMMARY

[0005] In view of the above problems, the present application provides a driving-free terahertz metamaterial sensor based on capillary micro flow channel, which uses the channel isolated by the metal unit array structure in the metamaterial layer as the capillary micro flow channel, utilizes the capillary phenomenon of liquid to make the liquid fill the micro flow channel by itself, and realizes the driving-free flow of liquid.

[0006] The present application provides a driving-free terahertz metamaterial sensor based on capillary micro flow channel, which comprises:

[0007] The metamaterial layer and the microcavity structure are connected in sequence from top to bottom in the vertical direction.

[0008] The connection mode of the metamaterial layer and the microcavity structure is detachable connection, realizing repeated use.

[0009] The metamaterial layer comprises a metal unit array structure 2, a capillary micro flow channel 4 and a first substrate 1; the capillary micro flow channel 4 is a channel isolated by the metal unit array structure 2 in the metamaterial layer.

[0010] The capillary micro flow channel can utilize the capillary phenomenon of liquid to make the liquid fill the micro flow channel by itself, and realize the driving-free flow of liquid.

[0011] Optionally, the microcavity structure comprises a first micro flow channel 5, a second micro flow channel 8, a solution inlet channel 6 and a solution outlet channel 7.

[0012] The first micro flow channel 5 and the second micro flow channel 8 are respectively connected to the bottom end and the top end of the metal unit array structure, and are used for connecting a plurality of unit capillary micro channels.

[0013] The solution inlet channel 6 is connected to the first micro flow channel 5 and adopts a stepped structure to maximize the guidance of liquid into the micro flow channel.

[0014] The solution outlet channel 7 is connected to the second micro flow channel 8 to ensure that the micro flow channel is in communication with air, which is a necessary condition for capillary self-suction.

[0015] Optionally, the metal unit array structure comprises a plurality of metal units 3, and the plurality of metal units are periodically arranged on the first substrate to form the capillary micro flow channel 4.

[0016] The metal unit 3 comprises a metal frame 1 3-1, a metal frame 2 3-2 and a unit capillary micro flow channel 3-3.

[0017] The metal frame 1 and the metal frame 2 are centrally symmetrical, and the unit capillary micro flow channel 3-3 is formed in the middle.

[0018] Optionally, each metal unit 3 is uniformly distributed in the horizontal and vertical directions, respectively, wherein in the vertical direction, each unit capillary micro flow channel is aligned and connected to form a plurality of metal unit structures; the plurality of metal unit structures are arranged in an equal-row-spacing column type to form a metal unit array structure.

[0019] Optionally, the metal frame 1 3-1 and the metal frame 2 3-2 have a rectangular outer contour shape.

[0020] The inner contour of the metal frame 1 3-1 and the metal frame 2 3-2 is a regular geometric shape composed of horizontal and vertical straight lines.

[0021] Optionally, the first micro flow channel 5 is connected to a solution inlet channel 6, and the solution inlet channel is arranged in the vertical direction.

[0022] The first micro flow channel 5 is connected to a plurality of unit capillary micro flow channels at the top end of the metal unit array structure.

[0023] Optionally, the second micro flow channel comprises a channel 1 8-1 and a channel 2 8-2.

[0024] The channel 1 8-1 and the channel 2 8-2 are connected vertically, and the channel 2 is also connected to a solution outlet channel 7, and the solution outlet channel 7 is arranged in parallel with the channel 1 8-1.

[0025] The solution outlet channel 7 is arranged in the horizontal direction.

[0026] The channel 1 8-1 is connected to a plurality of unit capillary micro flow channels at the bottom end of the metal unit array structure.

[0027] Optionally, a nano antenna or a plasmonic structure is embedded in the capillary micro flow channel.

[0028] Optionally, the nano antenna is a dipole antenna or a metamaterial structure.

[0029] The dipole antenna is a metal nanorod or a V-shaped antenna, which can directionally enhance the radiation and reception of terahertz waves.

[0030] Optionally, the material of the metal unit 3 is gold.

[0031] Compared with the prior art, the present application has at least the following beneficial effects:

[0032] (1) the super material of the present application is strictly selected from the metal gold with stable chemical properties and the fused quartz glass with low dielectric constant, so that the stability of the electromagnetic response characteristics of the super material is ensured, and the sensitivity of the super material is fully exerted;

[0033] (2) the micro flow channel formed by the metal part of the super material of the present application is naturally formed without additional processing, and the micro flow channel is naturally formed from the structural design without driving force, so that the equipment is simplified, the structure is compact, the processing difficulty is basically reduced to zero, and the processing cost is greatly reduced;

[0034] (3) the micro flow channel of the present application enables the measured liquid to be directly contacted, so that the change of the electromagnetic field regulated by the metal structure of the super material can directly act on the measured object, and the sensitivity of the super material sensor can be maximized;

[0035] (4) the micro flow channel of the present application requires a very small amount of measured liquid, which is in the order of microliters (μL), and can be used for micro flow solution detection, and the small amount of liquid can reduce the absorption of solution, especially water solution, to terahertz, so as to increase the detection range and enhance the reliability of the detection result;

[0036] (5) the capillary structure formed by the combination of the super material and the micro cavity of the present application can absorb liquid by itself due to capillary action, without the need for additional pumping device, so as to reduce the complexity of the super material sensor test structure, and the simple structure is also conducive to ensuring the stability of the device;

[0037] (6) the width of the micro flow channel of the present application is in the order of microns, and the depth is in the order of hundreds of nanometers, which can accommodate biological macromolecules to pass through, and the sensor chip is specially designed for biological macromolecule solution.

[0038] (7) the super material layer and the micro cavity of the present application can be detached and reused. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings are only for the purpose of illustrating specific embodiments and are not considered to be a limitation of the present application.

[0040] Figure 1 Fig. 1 is a schematic diagram of the structure of the present application based on the capillary micro flow channel without driving terahertz super material sensor;

[0041] Reference signs:

[0042] Second substrate 1, metal unit array structure 2, metal unit 3, metal frame 1 3-1, metal frame 2 3-2, unit capillary micro flow channel 3-3, capillary micro flow channel 4, first micro flow channel 5, solution inlet channel 6, solution inlet 6-1, solution outlet channel 7, channel 1 8-1, channel 2 8-2, second substrate 9. DETAILED DESCRIPTION

[0043] In order to enable more clear understanding of the above-mentioned purposes, features and advantages of the present application, the present application is further described in detail below in combination with the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. In addition, the present application can also be implemented in other ways different from those described herein, and therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0044] One specific embodiment of the present application, as Figure 1 , discloses a driven terahertz metamaterial sensor based on capillary micro flow channel, comprising: a metamaterial layer and a microcavity structure connected in turn from top to bottom in the vertical direction.

[0045] Optionally, the connection mode of the metamaterial layer and the microcavity structure is detachable connection, realizing repeated use.

[0046] Optionally, the metamaterial layer comprises a metal unit array structure 2, a capillary micro flow channel 4 and a first substrate 1; the capillary micro flow channel 4 is a channel isolated by the metal unit array structure 2 in the metamaterial layer.

[0047] The capillary micro flow channel can utilize the capillary phenomenon of liquid to make the liquid fill the micro flow channel by itself, realizing the driven flow of liquid.

[0048] Optionally, the metal unit array structure comprises a plurality of metal units 3, and the plurality of metal units are periodically arranged on the first substrate to form the capillary micro flow channel 4.

[0049] Optionally, the metal unit 3 comprises a metal frame one 3-1, a metal frame two 3-2 and a unit capillary micro flow channel 3-3.

[0050] The outer contour shape of the metal frame one 3-1 and the metal frame two 3-2 is rectangular.

[0051] The inner contour of the metal frame one 3-1 and the metal frame two 3-2 is a regular geometric figure composed of horizontal and vertical straight lines.

[0052] The metal frame one and the metal frame two are center-symmetric, and the unit capillary micro flow channel 3-3 is formed in the middle.

[0053] Optionally, each metal unit 3 is uniformly distributed along the horizontal and vertical directions, respectively, wherein along the vertical direction, each unit capillary micro flow channel is aligned and connected to form a plurality of column metal unit structures; the plurality of column metal unit structures are arranged in equal row spacing column type to form the metal unit array structure.

[0054] Optionally, the metal unit array structure 3 is arranged in whole column type, which is 100x100.

[0055] Optionally, the material of the first substrate is a polished silicon wafer or fused quartz glass.

[0056] Further, the material of the metal unit 3 is gold, which not only has a high conductivity σ = 4.561 × 107 S / m, but also has stability and is not easy to be oxidized in the order of nanometers, and does not react with the measured object, so as to ensure the stability of the electromagnetic response characteristics of the metamaterial.

[0057] Further, the material of the first substrate is fused quartz glass, which not only has good transmittance to terahertz waves, but also has a low dielectric constant of 1.75. The low dielectric constant of the substrate is conducive to fully exerting the sensitivity of the metamaterial sensor.

[0058] Optionally, the microcavity structure includes a cavity structure, a first micro-flow channel 5, a second micro-flow channel 8, a solution inlet channel 6, a solution outlet channel 7, and a second substrate 9.

[0059] The first micro-flow channel 5 and the second micro-flow channel are respectively connected to the bottom end and the top end of the metal unit array structure, and are used to connect a plurality of unit capillary micro-flow channels.

[0060] The solution inlet channel 6 is connected to the first micro-flow channel 5 and adopts a stepped structure to maximize the guidance of liquid into the micro-flow channel.

[0061] The solution outlet channel 7 is connected to the second micro-flow channel 8 to ensure that the micro-flow channel is in communication with air, which is a necessary condition for capillary self-suction.

[0062] Optionally, the second substrate 9 is a hollow rectangle, and the cavity structure, the first micro-flow channel 5, the solution inlet channel 6, the solution outlet channel 7, and the second micro-flow channel 8 are all arranged on the second substrate, and are sealed by atmospheric pressure and Van der Waals force to prevent liquid leakage.

[0063] Optionally, the metal unit array structure is embedded in the cavity structure.

[0064] The first micro-flow channel and the second micro-flow channel are connected to the cavity structure, which prevents liquid overflow after the microcavity structure and the metamaterial structure are combined.

[0065] Optionally, the first micro-flow channel 5 is connected to the solution inlet channel 6 in a vertical manner, and the solution inlet channel is arranged in a vertical direction.

[0066] The first micro-flow channel 5 is connected to a plurality of unit capillary micro-flow channels at the top end of the metal unit array structure.

[0067] Optionally, the second micro-flow channel includes a channel one 8-1 and a channel two 8-2.

[0068] The channel one 8-1 is connected with the channel two 8-2 vertically, and the channel two is also connected with the solution outlet channel 7 which is arranged parallel to the channel one 8-1;

[0069] The solution outlet channel 7 is arranged in the horizontal direction;

[0070] The channel one 8-1 is connected with a plurality of unit capillary micro flow channels at the bottom end of the metal unit array structure.

[0071] Optionally, after the super material layer and the micro cavity structure are assembled, the outer contour is connected with the outer contour of the metal unit array structure without gaps.

[0072] The second substrate is connected with the cavity structure and the micro flow channel 5.

[0073] It can be understood that the second substrate plays a supporting role in that the cavity structure and the micro flow channel 5 are attached to the second substrate 9 by micro-nano processing technology; and after the second substrate 9 and the first substrate 1 are attached and wetted, a sealing effect is formed due to the action of atmospheric pressure.

[0074] Further, the pattern structure composed of gold in the micro cavity structure surrounds the super material metal structure array pattern, and the annular channel reserved around the pattern structure is used as a micro flow channel, so that a complete capillary self-suction structure is formed. In particular, the channel depth of the capillary micro flow channel is the same as the thickness of gold.

[0075] The present application realizes a driving-free capillary self-suction + terahertz electromagnetic response, wherein the liquid transmission is driving-free: after the liquid is dropped in the solution inlet channel 6, the capillary phenomenon of the spontaneous flow of the liquid in the micron / nanometer scale channel is realized, and the liquid fills the capillary micro flow channel and the micro flow channel of the micro cavity structure by itself, and the whole process does not need a driving pump. The sealing design of the micro cavity structure ensures that the liquid does not leak out under the action of atmospheric pressure + van der Waals force after the attachment.

[0076] In the present application, the terahertz wave is vertically incident, first passes through the micro cavity structure, then enters the super material layer, and finally is emitted. The metal unit array of the super material has characteristics such as frequency of vibration and transmittance of terahertz wave. When the capillary micro flow channel is filled with the solution to be measured, the refractive index and concentration of the solution will change the electromagnetic environment around the super material, so as to modulate the transmission characteristics such as the resonance peak frequency shift and intensity change of the terahertz wave. Through the detection of the change of the terahertz wave, the sensitive measurement of the properties of the solution can be realized.

[0077] In the present application, the super material metal structure can naturally form a capillary channel, which is formed by the design of the metal structure without additional processing in the micro flow channel.

[0078] Optionally, the expression of the depth of the microfluidic channel is:

[0079] h=k1·w+k2 n n

[0080] wherein h is the depth, k1 is a constant related to the properties of the liquid, k2 is a constant related to the surface energy of the material, n is an index term, usually 0<n<1, and w is the width.

[0081] Optionally, the depth and width of the capillary microfluidic channel are consistent with those of the first microfluidic channel and the second microfluidic channel.

[0082] The depth and width of the solution inlet channel 6 and the solution outlet channel 7 are consistent with those of the capillary microfluidic channel.

[0083] Optionally, the width of the first microfluidic channel is 4-6 μm, which can accommodate the passage of biological macromolecules, and this sensor chip is specially designed for biological macromolecule solutions.

[0084] Optionally, the depth of the first microfluidic channel is 80 nm, 100 nm, 200 nm or 300 nm.

[0085] Further, the metal unit array structure and the microcavity structure are matched to form a self-suction terahertz metamaterial sensor chip, realizing sensitive measurement of trace solutions.

[0086] Optionally, the amount of the trace solution is in the order of microliters (μL).

[0087] Optionally, the metal unit array structure 2 is completely enclosed in the microfluidic channel 5.

[0088] The liquid is dropped into the solution inlet 6-1, and due to the capillary effect, the solution is automatically sucked into the microfluidic channel.

[0089] The solution outlet is used to ensure that the microfluidic channel is in communication with the air, ensuring the feasibility of capillary self-suction.

[0090] Illustratively, the depth of the capillary microfluidic channel is 80-300 nm, and the width of the capillary microfluidic channel is in the order of microns; by utilizing the capillary phenomenon of the liquid, the liquid can be automatically filled into the channel without a driving pump.

[0091] Optionally, a nano-antenna or plasmonic structure is embedded in the capillary microfluidic channel, significantly enhancing the interaction between terahertz waves and biomolecules, breaking through the limitations of sensitivity and resolution, improving the coupling efficiency of terahertz waves and biomolecules, and realizing subwavelength scale high-sensitivity detection.

[0092] Further, the nano-antenna is a dipole antenna or a metamaterial structure.

[0093] The dipole antenna is a metal nanorod or a V-shaped antenna, which can directively enhance the radiation and reception of terahertz waves.

[0094] The metamaterial structure is a fractal structure or a fishnet structure, which realizes wide-band electromagnetic response.

[0095] Further, the nanometer antenna material is metal gold, metal silver or graphene;

[0096] Optionally, the plasmonic structure is embedded in the capillary micro-flow channel.

[0097] Optionally, the plasmonic structure is embedded in the capillary micro-flow channel.

[0098] Optionally, the plasmonic structure is embedded in the capillary micro-flow channel.

[0099] The metal nanostructure can excite surface plasmon resonance LSPR, generate a strong electromagnetic field at the nanometer scale, and significantly enhance the interaction between terahertz waves and biomolecules. The periodic plasmonic structure can guide the terahertz wave to propagate along a specific path, and prolong the interaction time with the biomolecules.

[0100] In the present application, the width of the micro-flow channel is in the order of microns, and the depth is in the order of hundreds of nanometers. Due to the capillary action of the liquid, the liquid can fill the micro-flow channel by itself without the action of an external driving force (such as a driving pump).

[0101] The terahertz metamaterial sensor is used for measuring solutions and suspensions, and can be used for biological sensing such as protein solution, DNA solution, biological macromolecule solution and virus solution measurement; and can be used for non-biological solution measurement of different concentrations such as different concentrations of saline, alcohol solution and the like.

[0102] The second object of the present application is to provide an application of a driving-free terahertz metamaterial sensor based on a capillary micro-flow channel, which is used for micro-solution sensing in the terahertz wave band.

[0103] The micro-solution sensing in the terahertz wave band is used for biological sensing and chemical sensing.

[0104] The biological sensing includes biological macromolecule detection of protein solution, DNA solution and virus solution.

[0105] The chemical sensing includes non-biological solution detection of saline concentration and alcohol concentration.

[0106] In one embodiment of the present application, in use, the solution inlet channel of the non-driven terahertz metamaterial sensor is placed vertically upward, the terahertz wave is incident vertically to the plane where the metal unit array structure 2 is located, and the incident sequence of the terahertz wave is first through the microcavity structure, then incident to the metamaterial layer, and finally emitted from the sensor.

[0107] In use of the non-driven terahertz metamaterial sensor of the present application, the solution wets the metamaterial layer and the microcavity structure, under the action of atmospheric pressure and van der Waals force, the metamaterial layer and the microcavity structure can be self-tightly combined; the microchannel naturally formed by the metamaterial layer is sealed by the microcavity, finally forming a capillary structure, which can self-absorb the solution and ensure that the solution does not leak out.

[0108] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A driverless terahertz metamaterial sensor based on capillary microchannels, characterized in that, include: The metamaterial layers and microcavity structures are connected sequentially from top to bottom along the vertical direction; The connection between the metamaterial layer and the microcavity structure is detachable, allowing for reuse. The metamaterial layer includes a metal unit array structure (2), a capillary microfluidic channel (4), and a first substrate (1); the capillary microfluidic channel (4) is a channel isolated by the metal unit array structure (2) in the metamaterial layer; The capillary microfluidic channel utilizes the capillary phenomenon of liquids to allow the liquid to fill the microfluidic channel on its own, achieving a flow of liquid without driving force.

2. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, The microcavity structure includes a first microfluidic channel (5), a second microfluidic channel (8), a solution inlet channel (6), and a solution outlet channel (7); The first microfluidic channel (5) and the second microfluidic channel (8) are respectively connected to the bottom and top of the metal unit array structure, and are used to connect multiple unit capillary microchannels; The solution inlet channel (6) is connected to the first microfluidic channel (5) and adopts a stepped structure to maximize the guidance of liquid into the microfluidic channel; The solution outlet channel (7) is connected to the second microfluidic channel (8) to ensure that the microfluidic channel is connected to the air, which is a necessary condition for capillary self-absorption.

3. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, The metal unit array structure includes multiple metal units (3), which are periodically arranged on the first substrate to form capillary microfluidic channels (4). The metal unit (3) includes a first metal frame (3-1), a second metal frame (3-2), and a unit capillary microfluidic channel (3-3); The first metal frame and the second metal frame are centrally symmetrical, forming a unit capillary microfluidic channel (3-3) in the middle.

4. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 3, characterized in that, Each metal unit (3) is evenly distributed along the horizontal and vertical directions. In the vertical direction, the capillary microfluidic channels of each unit are aligned and connected to form a multi-column metal unit structure. The multi-column metal unit structure is arranged in an equal row-spaced column to form a metal unit array structure.

5. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 3, characterized in that, The outer contours of the first metal frame (3-1) and the second metal frame (3-2) are rectangular; The inner contours of the first metal frame (3-1) and the second metal frame (3-2) are regular geometric shapes composed of horizontal and vertical straight lines.

6. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 2, characterized in that, The first microfluidic channel (5) is vertically connected to the solution inlet channel (6), which is arranged in a vertical direction; The first microfluidic channel (5) connects multiple unit capillary microfluidic channels at the top of the metal unit array structure.

7. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 2, characterized in that, The second microfluidic channel includes channel one (8-1) and channel two (8-2); Channel 1 (8-1) is vertically connected to Channel 2 (8-2), and Channel 2 is also connected to Solution Outlet Channel (7). Solution Outlet Channel (7) is arranged parallel to Channel 1 (8-1). The solution outlet channel (7) is arranged in a horizontal direction; Channel 1 (8-1) connects multiple unit capillary microfluidic channels at the bottom of the metal unit array structure.

8. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, Embedding nanoantennas or plasmonic structures within capillary microfluidic channels.

9. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 8, characterized in that, The nanoantenna is a dipole antenna or a metamaterial structure; The dipole antenna is a metal nanorod or a V-shaped antenna, which can directionally enhance the radiation and reception of terahertz waves.

10. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 3, characterized in that, The material of the metal unit (3) is gold.

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