A metamaterial-based terahertz microfluidic sensor structure

Abstract

The application provides a terahertz micro-fluid sensor structure based on a metamaterial, which comprises a metal reflection cover plate, a micro-fluid channel layer, a metamaterial metal resonance structure layer and a substrate in sequence; the metamaterial metal resonance structure layer is provided with a metal hole array on the surface, and the thickness of the micro-fluid channel layer increases along the length direction of the metal hole array; the sensor structure has the characteristics that the spectral resonance peak amplitude can be obviously influenced by simply moving a detection area, can be used as a sensor for measuring the refractive index or concentration of a related liquid, and can realize the tunable function of the spectral intensity of a to-be-detected liquid, so that the same sensor can measure a wider range of refractive indexes.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of terahertz time-domain spectroscopy, and particularly relates to a terahertz microfluid sensor structure based on metamaterials. BACKGROUND

[0002] Metamaterial is an artificial electromagnetic material, which is usually composed of a periodic array of sub-wavelength, deep sub-wavelength resonator units. Under the excitation of incident electromagnetic waves, the resonance of resonator units produces many unique electromagnetic properties that natural materials do not have. By reasonably selecting materials and designing resonator unit structures, the required resonance properties can be flexibly realized. And near the resonance frequency, a strong local field enhancement effect is produced, so that the metamaterial has the characteristics of being extremely sensitive to the changes of the surrounding medium environment. Based on this characteristic, trace substance detection in the terahertz band can be realized.

[0003] The traditional sandwich structure sensor chip design can only detect the measured object under fixed structure parameters. Although the resonance can be adjusted through phase change materials, tunable materials and micro-electro-mechanical systems, the devices of this kind of tuning mode have a very high cost and depend on complex processing technology. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a terahertz microfluid sensor structure based on metamaterials, which solves the tunable problem through a simple control means on the basis of the traditional metamaterial device preparation process.

[0005] The present application achieves the above technical purpose through the following technical means.

[0006] A terahertz microfluid sensor structure based on metamaterials: a metal reflection cover plate, a microfluid channel layer, a metamaterial metal resonant structure layer and a substrate are sequentially arranged; the metamaterial metal resonant structure layer is provided with a metal hole array on the surface, and the thickness of the microfluid channel layer increases along the length direction of the metal hole array.

[0007] Further, the microfluid channel layer is injected with a measured liquid, and the spectral intensity is adjusted by adjusting the spectral detection area along the length direction of the metal hole array.

[0008] Further, the substrate material is polyimide, and the materials of the metamaterial metal resonant structure layer and the metal reflection cover plate are both aluminum.

[0009] Further, the substrate is a square structure with a size of 50*50mm, the thickness of the metal reflection cover plate is 1mm, the thickness of the metamaterial metal resonant structure layer is 20μm, the outer contour of the metal hole array is 40mm in length and 10-30mm in width, the diameter of the unit structure is 100-130μm, and the period is 200-250μm.

[0010] Further, the metal hole array outer contour is 10*40mm, wherein the unit structure diameter is 125μm, and the period is 236μm.

[0011] Further, the microfluidic channel layer thickness is 10-100μm, and the thickness difference between two ends is greater than 0 and less than or equal to 90μm.

[0012] Further, the microfluidic channel layer thickness is 10-100μm, and the thickness difference between two ends is greater than 0 and less than or equal to 90μm.

[0013] Further, the microfluidic channel layer thickness is 10-100μm, and the thickness difference between two ends is greater than 0 and less than or equal to 90μm.

[0014] Further, the microfluidic channel layer thickness is 10-100μm, and the thickness difference between two ends is greater than 0 and less than or equal to 90μm.

[0015] Further, the microfluidic channel layer thickness is 10-100μm, and the thickness difference between two ends is greater than 0 and less than or equal to 90μm.

[0016] The beneficial effects of the present application are:

[0017] (1) The present application provides a terahertz microfluidic sensor structure based on metamaterials, which has the characteristic that the spectral resonance peak amplitude can be significantly affected by simply moving the detection area, can be used as a sensor for measuring the refractive index or concentration of a related liquid, and can realize the function of adjusting the spectral intensity of the to-be-detected liquid, so that the same sensor can measure a wider range of refractive indexes.

[0018] (2) The sensor structure of the present application has a simpler manufacturing method than other tunable sensors, has a great advantage in processing cost, does not involve precision machining in the bonding process, and has a broader application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a sectional view of the sensor structure of the present application;

[0020] Figure 2 It is a perspective view of the sensor structure of the present application;

[0021] Figure 3 It is a spectral diagram detected by applying the sensor structure of the present application to distilled water at different regions thereon;

[0022] Figure 4 It is a spectral diagram detected by applying the sensor structure of the present application to alcohol at different regions thereon;

[0023] Figure 5 It is a spectral resonance peak frequency change diagram detected by applying the sensor structure of the present application to different regions thereon;

[0024] Figure 6 The graph shows the variation of the amplitude of the spectral resonance peak detected in different regions of the sensor structure of this invention.

[0025] Figure label:

[0026] 1-Metal reflective cover; 2-Glue pad; 3-Microfluidic channel layer; 4-Metamaterial metal resonant structure layer;

[0027] 41-Metal hole array; 5-Substrate; 6-Inlet; 7-Outlet. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein similar or identical reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] like Figure 1 and Figure 2 The illustrated terahertz microfluidic sensor structure based on metamaterials uses a polyimide film as a substrate 5, which has a square structure. A metamaterial metal resonant structure layer 4 is bonded onto the substrate using resin adhesive. The metamaterial metal resonant structure layer 4 can be made of aluminum film, with a metal hole array 41 fabricated on its upper surface. The outer contour of the metal hole array 41 is rectangular, with its four sides parallel to the four sides of the substrate 5. A metal reflective cover plate 1 is suspended above the metamaterial metal resonant structure layer 4, and the gap between the two is sealed with a gasket 2 to form a cavity serving as a microfluidic channel layer 3. The metal reflective cover plate 1 is slightly tilted relative to the metamaterial metal resonant structure layer 4, causing the thickness of the microfluidic channel layer 3 to increase gradually along the length of the metal hole array 41. Specifically, the thickness at both ends is 10–100 μm, and the thickness difference between the two ends is greater than 0 and less than or equal to 90 μm. An inlet 6 and an outlet 7 are respectively provided at two opposite corners of the metal reflective cover plate 1 to connect to the microfluidic channel layer 3. The metal reflective cover plate 1 can be made of aluminum.

[0030] Specifically, in this embodiment: the substrate 5 has a size of 50*50mm; the metal resonant structure layer 4 has a thickness of 20μm, and the outer contour of the metal hole array 41 on it is 40mm long and 10-30mm wide (the width of the test sample in this embodiment is 10mm), wherein the diameter of the unit structure (i.e., the metal hole) is 100-130μm (125μm in the test sample) and the period (i.e., the center distance between adjacent holes) is 200-250μm (236μm in the test sample); the metal reflective cover plate 1 has a thickness of 1mm; the microfluidic channel layer 3 has a thickness of 20μm at one end and 50μm at the other end along the inclined direction.

[0031] The sensor structure is injected with distilled water, and the sensor structure is detected by using a terahertz spectrometer, wherein four regions are selected in sequence along the length direction of the metal hole array 41 for detection, Figure 3 The detection results are shown in the figure, and A1 to A4 are the four selected detection regions, wherein the thickness of the microfluidic channel layer 3 in the A1 region is the thinnest, and the thickness of the microfluidic channel layer 3 in the A4 region is the thickest. Similarly, the sensor structure is injected with disinfectant alcohol (ethanol concentration 70% to 80%) and the spectrum is detected, and the results are shown in Figure 4 .

[0032] Figure 5 The resonant peak frequencies of the distilled water and the disinfectant alcohol spectrum measured in different detection regions are shown, and the average resonant peak frequency of the distilled water is calculated to be 0.5397 THz, and the standard deviation is 0.00458; the average resonant peak frequency of the disinfectant alcohol is 0.7138 THz, and the standard deviation is 0.00525. It can be seen that the change of the thickness of the microfluidic channel layer 3 in the sensor structure of the application has little effect on the resonant peak frequency of the spectrum of the liquid to be measured.

[0033] Figure 6 The resonant peak amplitude of the distilled water and the disinfectant alcohol spectrum measured in different detection regions is shown, and it can be seen that the resonant peak amplitude of the distilled water is the lowest in the A4 region, which is 10.56%; the resonant peak amplitude of the disinfectant alcohol is the lowest in the A1 region, which is 52.97%. It can be seen that the change of the thickness of the microfluidic channel layer 3 in the sensor structure of the application has little effect on the resonant peak amplitude of the spectrum of the liquid to be measured.

[0034] Based on the above characteristics, when the sensor structure of the application is applied to a sensor for measuring the refractive index or concentration of a liquid, the detection region can be simply moved along the length direction of the metal hole array 41 to realize the tunable function of the spectrum intensity, thereby bringing a wider refractive index measurement range.

[0035] In the description of the application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0036] The application is not limited to the above-mentioned embodiments, and any obvious improvements, replacements or modifications made by those skilled in the art without departing from the essential content of the application shall fall within the protection scope of the application.

Claims

1. A metamaterial-based terahertz microfluidic sensor structure, characterized by: From top to bottom are successively provided with a metal reflection cover plate (1), a microfluidic channel layer (3), a metamaterial metal resonance structure layer (4), a substrate (5); the surface of the metamaterial metal resonance structure layer (4) is provided with a metal hole array (41), and the thickness of the microfluidic channel layer (3) increases along the length direction of the metal hole array (41); The microfluidic channel layer (3) is injected with a to-be-tested liquid, and the spectral intensity is tuned by adjusting the spectral detection area along the length direction of the metal hole array (41); The substrate (5) is a square structure with a size of 50*50mm, the thickness of the metal reflection cover plate (1) is 1mm, the thickness of the metamaterial metal resonance structure layer (4) is 20μm, the outer contour of the metal hole array (41) is 40mm in length and 10-30mm in width, wherein the diameter of the unit structure is 100-130μm and the period is 200-250μm; the thickness of the microfluidic channel layer (3) is 10-100μm, and the thickness difference between the two ends is greater than 0 and less than or equal to 90μm; The material of the substrate (5) is polyimide, and the materials of the metamaterial metal resonance structure layer (4) and the metal reflection cover plate (1) are both aluminum; The metal reflection cover plate (1) is provided with a liquid inlet (6) and a liquid outlet (7) on the surface, and the two are respectively located at two opposite corners of the metal reflection cover plate (1).

2. The sensor structure of claim 1, wherein: The outer contour of the metal hole array (41) is 10*40mm, wherein the diameter of the unit structure is 125μm and the period is 236μm.

3. The sensor structure of claim 1, wherein: The thickness of the microfluidic channel layer (3) at one end is 20μm, and the thickness at the other end is 50μm.

4. The sensor structure of claim 1, wherein: The microfluidic channel layer (3) between the metal reflection cover plate (1) and the metamaterial metal resonance structure layer (4) is closed around by a rubber pad (2).

5. The sensor structure of claim 1, wherein: The metamaterial metal resonance structure layer (4) and the substrate (5) are adhered by resin.

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