A microcurrent sensing chip based on terahertz all-metal metamaterials

Abstract

The invention provides a microflow sensing chip based on a terahertz all-metal metamaterial, which comprises an all-metal metamaterial layer and a microflow channel, wherein the all-metal metamaterial layer is a layer of all-stainless steel metamaterial with a certain number of hollow patterns, the thickness is 0.05 mm, and the hollow pattern is a symmetrical dumbbell pattern; the microflow channel is attached to the surface of the all-metal metamaterial layer and covers the hollow pattern; the microflow channel comprises a microflow channel liquid inlet, a microflow channel middle part and a microflow channel liquid outlet; when the polarization direction of a vertically incident electromagnetic wave is along the dumbbell short axis, a magnetic ring dipole and an electric dipole can be excited, and a corresponding transmission peak is generated in a frequency range of 0.5-1.5 THz, and then a liquid to be tested enters from the liquid inlet of the microflow channel, directly contacts with the all-metal metamaterial layer, and then flows out from the liquid outlet of the microflow channel, and by detecting the peak wavelength drift of the transmission peak, high-sensitivity liquid refractive index detection in the frequency range of 0.5-1.5 THz can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement, and in particular to a micro-flow sensing chip based on terahertz all-metal metamaterial, which is mainly used for liquid refractive index detection. Background Art

[0002] A sensor is a detection device that can sense the information being measured and convert it into electrical signals or other required forms of information for output according to certain rules to meet the requirements of information transmission, processing, storage, display, recording and control. At present, sensors have been widely used in various fields of social development and human life, and play an increasingly important role in developing the economy and promoting social progress.

[0003] Metamaterials are artificial sub-wavelength electromagnetic metamaterials that have many properties that natural materials do not have, such as the ability to change the usual properties of light and electromagnetic waves. Such effects cannot be achieved with traditional materials, so metamaterials are one of the recent research hotspots in the electromagnetic field. There is nothing special about the composition of metamaterials. Their unique properties come from their precise geometric structure and size. The size of the microstructure is smaller than the wavelength of its action, so it can exert an influence on the wave. Its electromagnetic response can be characterized by equivalent dielectric constant and equivalent magnetic permeability. When the energy of incident light is coupled to the metamaterial, resonance can be generated, and a transmission valley or projection peak can be observed in the transmission spectrum. Since the resonance of metamaterials is sensitive to changes in the surrounding medium, metamaterials are often used in the field of sensing.

[0004] In the current existing technology, some metamaterial sensors can achieve refractive index detection in the GHz frequency range, but generally, the detection sensitivity of terahertz metamaterial refractive index sensors at home and abroad for certain trace substances or substances with small concentrations is not high enough, thus limiting the application of terahertz sensors. In addition, the spectrum resolution of the terahertz time-domain spectroscopy system currently used for experimental measurement is low, which affects the accuracy of sensor detection.

[0005] How to design a terahertz wave refractive index sensor that is simple in structure, easy to prepare, low in cost and suitable for mass production and can detect the refractive index of liquids in the THz frequency range is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to provide a microcurrent sensing chip based on terahertz all-metal metamaterials to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: The present invention provides a microcurrent sensing chip based on terahertz all-metal metamaterials, the specific contents of which are as follows:

[0008] The present invention provides a microflow sensing chip based on a terahertz all-metal metamaterial, comprising an all-metal metamaterial layer (1) and a microflow channel (2).

[0009] The surface of the all-metal metamaterial layer (1) is processed with a plurality of periodically arranged hollow patterns, and the hollow patterns are used as sensor units.

[0010] The microfluidic channel (2) comprises a microfluidic channel liquid inlet (4), a microfluidic channel middle part (3) and a microfluidic channel liquid outlet (5), one end of the microfluidic channel middle part (3) is connected to the microfluidic channel liquid inlet (4), and the other end of the microfluidic channel middle part (3) is connected to the microfluidic channel liquid outlet (5), and the three form a physically connected whole.

[0011] The microfluidic channel (2) is attached to the surface of the all-metal metamaterial layer (1) and covers the hollow pattern.

[0012] Preferably, the material of the all-metal metamaterial layer (1) is stainless steel, and the hollow patterns are arranged in a periodic pattern.

[0013] Preferably, the hollow pattern is a hollow dumbbell pattern formed by a square unit plus a rectangular unit plus a square unit.

[0014] Preferably, the microfluidic channel (2) is made of polydimethylsiloxane material PDMS using soft etching technology.

[0015] Preferably, the microfluidic channel liquid inlet (4) and the microfluidic channel liquid outlet (5) are manufactured through a flushing process.

[0016] The operating waveband of the microfluidic sensing chip is the terahertz waveband. When the electric field direction is incident along the TE wave, a magnetic ring dipole and an electric dipole are generated. The two interfere to generate a transmission peak. The liquid to be tested enters from the microfluidic channel liquid inlet (4), directly contacts the all-metal metamaterial layer (1), and then flows out from the microfluidic channel liquid outlet (5). The refractive index of the liquid to be tested can be detected by detecting the peak wavelength drift of the transmission peak.

[0017] The present invention discloses the following technical effects: The microcurrent sensing chip based on terahertz all-metal metamaterial proposed by the present invention adopts an all-metal metamaterial structure, and a hollow dumbbell pattern is processed on the surface of the all-metal metamaterial layer, which can simultaneously generate magnetic ring dipoles and electric dipoles. The transmission peak generated by the interference between the two has a narrower half-height full width than the transmission peak generated by a single electric dipole, and has better sensing performance. The pattern structure is simple and can be processed by laser engraving. The production cost is low and it is easy to process, taking into account the difficulty of micron-level laser processing and the sensing requirements of higher sensitivity. Through the design of metamaterial structure, high-sensitivity liquid refractive index detection of 661.38GHz / RIU can be achieved in the frequency range of 0.5THz-1.5THz. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 This is a schematic diagram of the structure of a microcurrent sensing chip based on terahertz all-metal metamaterials of the present invention;

[0020] Figure 2 This is a schematic diagram of the structural dimensions of the hollow unit of the all-metal metamaterial of the present invention;

[0021] Figure 3 This is a schematic diagram of the periodic arrangement of hollow units of the all-metal metamaterial of the present invention;

[0022] Figure 4 is the surface current diagram at Z = 50 microns;

[0023] Figure 5 is the magnetic field diagram at Y = 0 micrometers;

[0024] Figure 6 In the frequency range of 0.5THz-1.5THz, the transmission spectrum curve of the refractive index changes from 1 to 1.4;

[0025] Figure 7 It is the linear fitting graph of refractive index and corresponding peak wavelength.

[0026] in, Figure 1 In the middle, 1 is the all-metal metamaterial layer, 2 is the liquid inlet of the microfluidic channel, 3 is the middle part of the microfluidic channel, and 4 is the liquid outlet of the microfluidic channel.

[0027] Figure 2In the figure, M is the side length of the square unit in the dumbbell hollow pattern, L is the length of the rectangular unit, and W is the width of the rectangular unit. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1-7 The schematic diagram of the structure of the microcurrent sensing chip based on terahertz all-metal metamaterials of the present invention is shown in FIG. Figure 1 As shown, the microfluidic sensing chip includes a full metal metamaterial layer 1 and a microfluidic channel 2, wherein the microfluidic channel 2 includes a microfluidic channel liquid inlet 4, a microfluidic channel middle part 3 and a microfluidic channel liquid outlet 5. The full metal metamaterial layer 1 is made of stainless steel with a thickness of 50 um.

[0031] like Figure 2 As shown, it is a schematic diagram of the structural dimensions of the hollow unit of the all-metal metamaterial of the present invention. From a functional perspective, each hollow pattern can be regarded as a sensor unit for measuring the refractive index of liquid. The hollow patterns are arranged in a periodic pattern of 100×100 in the XY plane where the all-metal metamaterial layer 1 is located. Each hollow pattern is a square unit plus a rectangular unit plus a square unit along the X-axis direction. The side length of the square unit is M=40um, the length of the rectangular unit is L=40um, and the width is W=20um. In terms of shape, it can be regarded as a symmetrical dumbbell pattern. And the hollow units are processed in the periodically arranged rectangular units. The dimensions of the periodically arranged rectangular units are px=150 microns*py=120 microns in the horizontal direction, and the periodic arrangement is as follows: Figure 3 As shown, it is a schematic diagram of the periodic arrangement of the hollow units of the all-metal metamaterial of the present invention.

[0032] The microfluidic channel 2 is made of polydimethylsiloxane material PDMS using soft etching technology, and then a microfluidic channel liquid inlet 4 and a microfluidic channel liquid outlet 5 are made at both ends of the microfluidic channel 2 using a flushing process. The microfluidic channel 2 is a whole composed of the microfluidic channel liquid inlet 4, the microfluidic channel middle part 3 and the microfluidic channel liquid outlet 5, and the microfluidic channel 2 is covered on the all-metal metamaterial layer 1 and covers the hollow pattern. When the microfluidic sensing chip is working, the liquid to be tested is injected from the microfluidic channel liquid inlet 4, flows through the microfluidic channel middle part 3 and then flows out through the microfluidic channel liquid outlet 5, forming a working state of all-metal metamaterial layer-liquid to be tested-microfluidic channel.

[0033] When the polarization direction of the vertically incident electromagnetic wave is along the short axis of the dumbbell, a magnetic ring dipole and an electric dipole can be excited, and a corresponding transmission peak is generated in the frequency range of 0.5-1.5THz. Then the liquid to be tested enters from the microfluidic channel liquid inlet 4, directly contacts the all-metal metamaterial layer 1, and then flows out from the microfluidic channel liquid outlet 5. By detecting the peak wavelength drift of the transmission peak, high-sensitivity liquid refractive index detection in the frequency range of 0.5-1.5THz can be achieved.

[0034] Figure 4-6 : is a simulation test result diagram of this embodiment. When the microcurrent sensing chip based on terahertz all-metal metamaterial of the present invention is in working state and electromagnetic waves are incident on the surface of the sensor chip, a variable surface current will be generated on the metal surface of the sensor chip, such as Figure 4 This is the surface current diagram at Z = 50 microns. Since this surface current is changing, a magnetic field will be generated, such as Figure 5 : is the magnetic field diagram at Y=0 micrometer in this embodiment. By using liquids with different refractive indices to conduct experiments, a fitting relationship diagram between the frequency of incident electromagnetic waves with different frequencies and the refractive index of liquids with different refractive indices can be obtained. Figure 6 is the transmission spectrum curve when the refractive index of the liquid changes from 1 to 1.4 in the frequency range of 0.5THz-1.5THz. Figure 7 It is a linear fitting diagram of the refractive index and the corresponding peak wavelength. It is verified that the sensor chip of the present invention adopts the metamaterial structure design and can achieve high-sensitivity liquid refractive index detection of 661.38GHz / RIU in the frequency range of 0.5THz-1.5THz.

[0035] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0036] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A microcurrent sensing chip based on terahertz all-metal metamaterial, characterized by: It includes an all-metal metamaterial layer (1) and a microfluidic channel (2); The surface of the all-metal metamaterial layer (1) is processed with a plurality of periodically arranged hollow patterns, and the hollow patterns are used as sensor units; The microfluidic channel (2) comprises a microfluidic channel liquid inlet (4), a microfluidic channel middle part (3) and a microfluidic channel liquid outlet (5), one end of the microfluidic channel middle part (3) is connected to the microfluidic channel liquid inlet (4), the other end of the microfluidic channel middle part (3) is connected to the microfluidic channel liquid outlet (5), and the three form a physically connected whole; The microfluidic channel (2) is attached to the surface of the all-metal metamaterial layer (1) and covers the hollow pattern, wherein the hollow pattern is a hollow dumbbell pattern formed by a square unit, a rectangular unit and a square unit; The operating waveband of the microfluidic sensing chip is the terahertz waveband. When the electric field direction is incident along the TE wave, a magnetic ring dipole and an electric dipole are generated. The two interfere to generate a transmission peak. The liquid to be tested enters from the microfluidic channel liquid inlet (4), directly contacts the all-metal metamaterial layer (1), and then flows out from the microfluidic channel liquid outlet (5). The refractive index of the liquid to be tested can be detected by detecting the peak wavelength drift of the transmission peak.

2. The microcurrent sensing chip based on terahertz all-metal metamaterial according to claim 1 is characterized in that: The material of the all-metal metamaterial layer (1) is stainless steel, and the hollow patterns are arranged in a periodic pattern.

3. The microcurrent sensing chip based on terahertz all-metal metamaterial according to claim 1, characterized in that: The microfluidic channel (2) is made of polydimethylsiloxane material PDMS using a soft etching technique.

4. The microcurrent sensing chip based on terahertz all-metal metamaterial according to claim 1, characterized in that: The microfluidic channel liquid inlet (4) and the microfluidic channel liquid outlet (5) are manufactured through a flushing process.

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