A microfluidic sensing chip based on terahertz topological photonic crystal waveguide and its fabrication method

Abstract

This invention relates to the field of microfluidic sensor chip technology, and more particularly to a microfluidic sensor chip based on a terahertz topological photonic crystal waveguide and its fabrication method. This invention utilizes a microfluidic channel structure to reduce the absorption of terahertz electromagnetic waves by polar substances in the sample, thus achieving high detection sensitivity and low sample consumption. By applying the defects-immunizing and backscattering characteristics of the topological photonic crystal waveguide, the yield rate and signal-to-noise ratio of the sensor can be improved. The characteristics of the topological transmission edge states are used to precisely confine electromagnetic wave energy within the microfluidic channel range, thereby improving the sensor's sensitivity. Furthermore, a piezoelectric ceramic micropump enables high-precision sample feeding, simplifying the usage steps and reducing the integrated volume. A bubble separation device addresses the problem of increased injection pressure caused by bubble suspension in microgravity environments, ensuring the stability of the chip's operation. Moreover, this microfluidic sensor chip is suitable for microgravity environments.

Description

Technical Field

[0001] This invention relates to the field of microfluidic sensor chip technology, and in particular to a microfluidic sensor chip based on a terahertz topological photonic crystal waveguide and its fabrication method. Background Technology

[0002] Terahertz sensing is a technology that uses electromagnetic radiation in the terahertz band for detection and imaging. This band lies between microwaves and infrared radiation, with a frequency range of 0.1 to 10 THz. Terahertz waves have low energy, do not produce ionizing radiation, and are safe for biological tissues. Many organic molecules and biomolecules have unique absorption characteristics in the terahertz band. Utilizing this, terahertz sensors can identify different substances by analyzing the spectral characteristics of samples, which is very useful for chemical composition analysis. However, terahertz waves are sensitive to polar molecules, which greatly attenuate the energy of terahertz electromagnetic waves.

[0003] Currently, the main approach is to design subwavelength metasurface structures and leverage the effect of locally enhanced electric fields within these structures to place the detection channel within the enhanced electric field region, thereby improving detection sensitivity. While metasurface structure chips can be miniaturized and integrated, their fabrication process is complex and yields low success rates. This technology requires a device to focus terahertz electromagnetic waves onto the sensor, such as a mechanical structure combining a TPX lens and an optical slide. Signal coupling needs to be debugged before experiments, increasing the workload of astronaut training. Furthermore, the system's size is difficult to reduce, making it unsuitable for use in space stations and other volume-sensitive detection missions.

[0004] Based on microfluidic chip technology, the position of the sample in the microfluidic channel can be precisely controlled, thereby achieving precise temporal and spatial coupling between the sample and terahertz electromagnetic waves, improving the response of terahertz electromagnetic waves to the sample, and thus enhancing the sensitivity of the sensor. However, in a microgravity environment, due to the absence of convection, buoyancy, and hydrostatic pressure, the liquid is mainly affected by surface tension. This leads to the cessation of density-driven convection, and the gas and liquid do not spontaneously separate, posing challenges to bubble management. Furthermore, the accumulation of bubbles in the microfluidic channel can cause a sudden increase in injection pressure, resulting in blank gaps between samples in the channel that affect detection results, and may even lead to sample injection failure in the microfluidic channel, rendering the sensor inoperable.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a microfluidic sensing chip based on terahertz topological photonic crystal waveguide and its fabrication method, aiming to solve the problems of existing microfluidic sensing chips being large in size, difficult to manufacture, and unsuitable for microgravity environments.

[0007] The technical solution of the present invention is as follows:

[0008] A microfluidic sensing chip based on a terahertz topological photonic crystal waveguide includes:

[0009] The housing includes a first receiving cavity, a second receiving cavity, and a base fixing platform disposed between the first receiving cavity and the second receiving cavity;

[0010] A bubble separation device and a piezoelectric ceramic micropump are provided, wherein the bubble separation device and the piezoelectric ceramic micropump are connected by a pipeline and are disposed in the first receiving cavity;

[0011] A waste liquid tank is disposed within the second receiving cavity;

[0012] A substrate is disposed on a fixed platform. An A-type topological photonic crystal, a B-type topological photonic crystal, and a microfluidic channel are disposed on the substrate. A topological transport path is provided at the interface between the A-type and B-type topological photonic crystals. The microfluidic channel partially overlaps with the topological transport path. A thin film is provided on the side of the microfluidic channel away from the housing, and a channel inlet is provided at the end of the microfluidic channel near the bubble separation device, and a channel outlet is provided at the end near the waste liquid tank.

[0013] The liquid inlet seat and the liquid outlet seat are provided, wherein the liquid inlet seat is located at the liquid inlet of the channel and the liquid outlet seat is located at the liquid outlet of the channel.

[0014] The microfluidic sensing chip based on terahertz topological photonic crystal waveguide is wherein the substrate material has a refractive index greater than 1.2 and an absorption coefficient less than 50 / mm in the operating frequency range of 0.1THz to 10THz.

[0015] The microfluidic sensing chip based on terahertz topological photonic crystal waveguides includes an A-type topological photonic crystal composed of multiple periodic topological photonic crystal cell units, and a B-type topological photonic crystal composed of multiple periodic topological photonic crystal cell units rotated 180° around their geometric center; each topological photonic crystal cell unit is provided with a first air hole and a second air hole.

[0016] The microfluidic sensing chip based on terahertz topological photonic crystal waveguide has a lattice constant of 1 μm to 1 mm.

[0017] The microfluidic sensing chip based on terahertz topological photonic crystal waveguide, wherein the topological transmission path is formed by the junction of the type A topological photonic crystal and the type B topological photonic crystal.

[0018] The microfluidic sensing chip based on terahertz topological photonic crystal waveguide, wherein the microfluidic channel and the topological transmission path overlap by at least one lattice period.

[0019] The microfluidic sensing chip based on terahertz topological photonic crystal waveguide is provided with signal coupling ports at both the start and end of the topological transmission path.

[0020] The microfluidic sensing chip based on terahertz topological photonic crystal waveguide is provided with a micropump electrical interface and a micropump liquid inlet on the piezoelectric ceramic micropump.

[0021] The microfluidic sensing chip based on terahertz topological photonic crystal waveguide is described above, wherein the waste liquid tank is provided with a waste liquid tank inlet and a waste liquid tank outlet; the waste liquid tank inlet is connected to the outlet seat; and the inlet seat is connected to the bubble separation device.

[0022] A method for fabricating a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide includes the following steps:

[0023] A topological transmission path is set on the substrate to divide the substrate into a type A topological photonic crystal region and a type B topological photonic crystal region;

[0024] Type A topological photonic crystals and Type B topological photonic crystals are respectively disposed in the Type A topological photonic crystal region and the Type B topological photonic crystal region;

[0025] A microfluidic channel is disposed on the substrate, and the microfluidic channel partially overlaps with the topology transmission path;

[0026] A thin film is prepared on the side of the microfluidic channel away from the substrate. The thin film covers the regions of the substrate excluding the type A topological photonic crystal region and the type B topological photonic crystal region, as well as the microfluidic channel.

[0027] An inlet seat and an outlet seat are respectively provided at both ends of the microfluidic channel;

[0028] A bubble separation device, a piezoelectric ceramic micropump, a waste liquid tank, and the substrate are mounted on a housing. The bubble separation device and the piezoelectric ceramic micropump are connected through a pipe. The bubble separation device is connected to the liquid inlet seat, and the waste liquid tank is connected to the liquid outlet seat, thus obtaining a microfluidic sensing chip.

[0029] Beneficial Effects: This invention provides a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide and its fabrication method. The microfluidic sensing chip includes: a housing with a first receiving cavity, a second receiving cavity, and a substrate fixing platform disposed between the first receiving cavity and the second receiving cavity; a bubble separation device and a piezoelectric ceramic micropump, wherein the bubble separation device and the piezoelectric ceramic micropump are connected by a pipe and disposed within the first receiving cavity; a waste liquid tank disposed within the second receiving cavity; and a substrate disposed on the substrate fixing platform; the substrate has an A... The system includes a type A topological photonic crystal, a type B topological photonic crystal, and a microfluidic channel. A topological transmission path is provided at the interface between the type A and type B topological photonic crystals. The microfluidic channel partially overlaps with the topological transmission path. A thin film is provided on the side of the microfluidic channel away from the housing, and a channel inlet is provided at one end of the microfluidic channel near the bubble separation device, and a channel outlet is provided at one end near the waste liquid tank. An inlet seat and an outlet seat are also provided, with the inlet seat located at the channel inlet and the outlet seat located at the channel outlet. This invention utilizes a microfluidic channel structure to reduce the absorption of terahertz electromagnetic waves by polar substances in the sample, thus achieving high detection sensitivity and low sample consumption. By applying the defects-immunizing and backscattering characteristics of topological photonic crystal waveguides, the yield rate and signal-to-noise ratio of sensor production can be improved. Furthermore, the characteristics of topological transmission edge states are used to precisely confine electromagnetic wave energy within the microfluidic channel, enhancing sensor sensitivity. Additionally, a piezoelectric ceramic micropump enables high-precision sample feeding, simplifying usage and reducing integrated volume. A bubble separation device addresses the issue of increased injection pressure due to bubble suspension in microgravity environments, ensuring chip stability. The microfluidic sensor chip provided by this invention is a highly integrated sensor, reducing experimental operation difficulty and learning costs for astronauts. Therefore, this microfluidic sensor chip is suitable for experimental research in the confined environment of a space station. Attached Figure Description

[0030] Figure 1 This is a front view schematic diagram of a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide according to the present invention.

[0031] Figure 2 This is a schematic diagram of the structural assembly of a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide according to the present invention.

[0032] Figure 3 The electric field distribution of the microfluidic sensing chip based on the terahertz topological photonic crystal waveguide of this invention is shown in the 0.27THz terahertz electromagnetic wave distribution diagram.

[0033] Figure 4 This is a schematic diagram of the structure of a unit cell in a topological photonic crystal.

[0034] Figure 5 The S21 parameter diagram of a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide is shown.

[0035] Figure 6 This is a schematic diagram of the substrate structure of a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide.

[0036] Figure 7 This is a schematic diagram of the substrate structure of a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide.

[0037] Explanation of reference numerals in the attached drawings: 10 housing, 11 first receiving cavity, 12 second receiving cavity, 13 substrate fixing platform, 20 bubble separation device, 21 pipe, 30 piezoelectric ceramic micropump, 31 micropump electrical interface, 32 micropump liquid inlet, 40 waste liquid tank, 41 waste liquid tank inlet, 42 waste liquid tank outlet, 50 substrate, 51 type A topological photonic crystal, 511 topological photonic crystal cell unit, 512 first air hole, 513 second air hole, 52 type B topological photonic crystal, 521 topological photonic crystal cell unit, 53 microchannel, 531 channel inlet, 532 channel outlet, 54 topological transmission path, 541 signal coupling port, 60 thin film, 61 through hole, 70 inlet seat, 80 outlet seat. Detailed Implementation

[0038] This invention provides a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide and its fabrication method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0040] With the advancement of human technology, many unknown experimental phenomena await exploration under microgravity conditions. In a gravity environment, the application of microfluidic technology and terahertz sensing technology to manufacture sensors offers numerous advantages. Microfluidic chip technology is a technique for precisely controlling and manipulating fluids at the micrometer scale. It integrates basic operational units such as sample preparation, reaction, separation, and detection in biological, chemical, and medical analysis processes onto a single micrometer-scale chip. This technology can automate the entire analytical process and offers advantages such as controllable liquid flow, minimal sample and reagent consumption, and rapid analysis speed.

[0041] Microfluidic chips require precise liquid-driven control to achieve accurate control of fluid pressure, flow rate, and position. Traditional liquid-driven methods primarily use peristaltic pumps and mechanical syringe pumps as power sources. These are dozens of times larger than sensor chips, making them unsuitable for volume-sensitive detection tasks such as those used in space stations. Peristaltic pumps offer continuous high flow rates, enabling rapid liquid delivery in short periods, but their precision is inferior to mechanical syringe pumps. Mechanical syringe pumps can achieve high-precision liquid driving, but the liquid must be transferred to a syringe before use, and the maximum volume of liquid pumped in a single operation is limited by the syringe volume. Continuous liquid pumping requires multiple mechanical syringe pumps operating alternately.

[0042] Furthermore, in microgravity environments, existing microfluidic chips suffer from the lack of convection, buoyancy, and hydrostatic pressure. Liquids are primarily affected by surface tension, leading to the cessation of density-driven convection and the absence of spontaneous gas-liquid separation. This presents challenges for bubble management. Bubble accumulation within microfluidic channels can cause a sudden increase in injection pressure, resulting in gaps between samples that affect detection results and may even lead to sample introduction failure.

[0043] Therefore, due to the limitations of current technology, there is a need for a terahertz microfluidic sensor chip that is small in size, easy to operate, and suitable for microgravity environments.

[0044] Based on this, such as Figure 1 and Figure 2 As shown, this invention provides a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide, comprising:

[0045] The housing 10 has a first receiving cavity 11, a second receiving cavity 12, and a base fixing platform 13 disposed between the first receiving cavity 11 and the second receiving cavity 12;

[0046] A bubble separation device 20 and a piezoelectric ceramic micropump 30 are connected by a pipe 21 and are disposed in the first receiving cavity 11.

[0047] Waste liquid tank 40 is disposed within the second receiving cavity 12;

[0048] A substrate 50 is disposed on the substrate fixing platform 13; an A-type topological photonic crystal 51, a B-type topological photonic crystal 52, and a microfluidic channel 53 are disposed on the substrate 50; a topological transmission path 54 is provided at the junction of the A-type topological photonic crystal 51 and the B-type topological photonic crystal 52; the microfluidic channel 53 and the topological transmission path 54 partially overlap; a thin film 60 is provided on the side of the microfluidic channel 53 away from the housing 10, and a channel inlet 531 is provided at one end of the microfluidic channel 53 near the bubble separation device 20, and a channel outlet 532 is provided at one end of the microfluidic channel 53 near the waste liquid tank 40;

[0049] Liquid inlet seat 70 and liquid outlet seat 80 are provided, wherein the liquid inlet seat 70 is provided at the liquid inlet 531 of the channel and the liquid outlet seat 80 is provided at the liquid outlet 532 of the channel.

[0050] In this embodiment, the application of a microfluidic channel structure reduces the absorption of terahertz electromagnetic waves by polar substances in the sample, resulting in high detection sensitivity and low sample consumption. The utilization of the defects-immunizing and backscattering characteristics of topological photonic crystal waveguides improves the yield and signal-to-noise ratio of sensor production. The use of topological transmission edge states precisely confines electromagnetic wave energy within the microfluidic channel range, enhancing sensor sensitivity. Furthermore, a piezoelectric ceramic micropump enables high-precision sample feeding, simplifying usage and reducing integrated volume. A bubble separation device addresses the issue of increased injection pressure due to bubble suspension in microgravity environments, ensuring chip stability. The microfluidic sensor chip provided by this invention is a highly integrated sensor, reducing experimental difficulty and learning costs for astronauts. Therefore, this microfluidic sensor chip is suitable for experimental research in the confined environment of a space station.

[0051] Specifically, this invention utilizes the properties of topological photonic crystal waveguides to immunely manufacture defects and backscatter, thereby improving the yield and signal-to-noise ratio of the sensor. For example... Figure 3As shown, by utilizing the characteristics of topological transmission edge states, electromagnetic wave energy can be precisely confined within the microfluidic channel, thereby improving the sensor's sensitivity. Water molecules in the air absorb terahertz electromagnetic waves, causing the terahertz signal to oscillate and affecting experimental results. Traditional terahertz sensors require an environment with relative humidity below 5% and use TPX and an optical displacement stage for signal coupling. However, the microfluidic sensing chip of this invention, based on a terahertz topological photonic crystal waveguide, only needs a terahertz electromagnetic wave signal coupled to the sensor through a terahertz band metal waveguide or a terahertz near-field antenna at the signal coupling port. This simplifies the steps of adjusting the optical path and the corresponding auxiliary equipment, and eliminates the need to maintain an experimental environment with relative humidity below 5%. Therefore, compared to traditional terahertz sensors, it has better environmental adaptability and achieves weight and volume reduction, making it easier to launch into the microgravity environment of a space station for experiments.

[0052] In some embodiments, the substrate 50 is made of a material with a refractive index greater than 1.2 and an absorption coefficient less than 50 / mm in the operating frequency range of 0.1THz to 10THz; the topological photonic crystal waveguide operates in the frequency range of 0.1THz to 10THz.

[0053] Terahertz radiation refers to electromagnetic waves with frequencies between 0.1 and 10 terahertz and wavelengths ranging from 3 millimeters to 30 micrometers, falling between microwaves and infrared radiation. Terahertz sensing technology offers several advantages. Terahertz waves can interact with the vibrational modes of molecules in matter, enabling precise detection of the composition and structure of substances. This characteristic allows terahertz sensors to detect trace amounts of chemical substances or biomolecules. Terahertz radiation can penetrate many nonpolar materials but is highly sensitive to polar molecules, which can be used to detect polar molecules in samples. Because the energy level of terahertz radiation is lower than that of X-rays, it does not cause ionizing damage, which is particularly important in applications where there is insufficient protection against ionizing radiation, protecting the safety of samples and experimental personnel. Based on the different terahertz spectral responses of different substances, various substances can be distinguished by analyzing absorption characteristics at specific frequencies, which is highly beneficial for the qualitative and quantitative analysis of target components in complex mixtures.

[0054] In a preferred embodiment, the substrate is made of high-resistivity silicon.

[0055] In some implementations, such as Figure 4 As shown, the type A topological photonic crystal 51 is composed of multiple periodic topological photonic crystal cell units 511, and the type B topological photonic crystal 52 is composed of multiple periodic topological photonic crystal cell units 521 rotated 180° around the geometric center; the topological photonic crystal cell unit is provided with a first air hole 512 and a second air hole 513.

[0056] In some embodiments, the lattice constant of the topological photonic crystal unit cell is 1 μm to 1 mm.

[0057] Specifically, both the first air hole 512 and the second air hole 513 are equilateral triangles. Preferably, the lattice constant of the topological photonic crystal cell unit is 340 μm, the side length of the equilateral triangle of the first air hole is 244.75 μm, and the side length of the equilateral triangle of the second air hole is 140.80 μm. The operating frequency range of the sensor chip is determined by the lattice constant, the side length of the equilateral triangle of the first air hole, and the side length of the equilateral triangle of the second air hole. In this embodiment, for example... Figure 5 The S21 parameters shown indicate that the sensor chip operates at a frequency of 0.259THz to 0.284THz.

[0058] In some implementations, such as Figure 6 and Figure 7 As shown, the topological transmission path is formed by the boundary between the type A topological photonic crystal and the type B topological photonic crystal. By utilizing the characteristics of the edge states of topological transmission, electromagnetic wave energy can be precisely confined within the microfluidic channel, thereby improving the sensitivity of the sensor.

[0059] In this embodiment, the bubble separation device 20, the piezoelectric ceramic micropump 30, the waste liquid tank 40, and the substrate 50 are all fixed to the housing 10, which can protect the internal components of the sensor chip under high-acceleration environments. The bubble separation device 20 can filter out suspended bubbles in the sample to ensure stable sensor operation; the piezoelectric ceramic micropump 30 features small size, high flow rate, high precision, high pressure, and simple driving, which helps to reduce the size of the microfluidic sensor chip provided by this invention.

[0060] In some implementations, the microfluidic channel and the topological transport path overlap by at least one lattice period. The overlapping region is the area where the sample interacts with terahertz electromagnetic waves. The more overlapping lattice periods there are, the higher the sensor sensitivity will be, but it will also destroy the topological edge states to a greater extent and increase the insertion loss of the sensor.

[0061] In a preferred embodiment, the microfluidic channel overlaps with the topological transport path for 15 lattice periods.

[0062] In some embodiments, signal coupling ports 541 are provided at both the start and end of the topology transmission path 54. The microfluidic sensing chip can couple terahertz electromagnetic wave signals to the sensor through a terahertz band metal waveguide or terahertz near-field antenna at the signal coupling port, simplifying the steps of adjusting the optical path and the corresponding auxiliary equipment. Moreover, it does not require maintaining an experimental environment with a relative humidity of less than 5%, thus exhibiting better environmental adaptability compared to traditional terahertz sensors. It also achieves a reduction in weight and volume, making it easier to launch into the microgravity environment of the space station for experiments.

[0063] In some embodiments, the piezoelectric ceramic micropump 30 is provided with a micropump electrical interface 31 and a micropump liquid inlet 32.

[0064] In some embodiments, the waste liquid tank 40 is provided with a waste liquid tank inlet 41 and a waste liquid tank outlet 42; the waste liquid tank inlet 41 is connected to the outlet seat 80; and the inlet seat 70 is connected to the bubble separation device 20.

[0065] Specifically, before starting the test, the sample conduit is inserted into the micropump inlet 32, the piezoelectric ceramic micropump driver cable is connected to the micropump electrical interface 31, the terahertz electromagnetic wave signal is coupled to the signal coupling port 541, and the piezoelectric ceramic micropump 30 is started. The sample to be tested is drawn from the micropump inlet 32 ​​by the piezoelectric ceramic micropump 30, flows through the pipe 21 and enters the bubble separation device 20. The bubble separation device 20 removes the bubbles suspended in the liquid sample. The bubble-free sample enters the microfluidic channel 53 from the inlet seat 70 and flows from the outlet seat 80 to the waste liquid inlet 41 and is stored in the waste liquid tank 40. After the test is completed, the waste liquid is discharged from the waste liquid outlet 42.

[0066] In some embodiments, the film 60 is provided with through holes 61 corresponding to the channel inlet 531 and the channel outlet 532, and the inlet seat 70 and the outlet seat 80 are disposed on the side of the film 60 away from the substrate and correspond to the through holes.

[0067] In some embodiments, the material of the film is selected from, but not limited to, one or more of polydimethylsiloxane, polyethylene, polypropylene, polybutene, polytetrafluoroethylene, polyester, silicone rubber, cyclic olefin copolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, polyphenylene sulfide, polyvinylidene fluoride-hexafluoropropylene copolymer, polyurethane, and polyester; the thickness of the film ranges from 1 μm to 5 mm.

[0068] In addition, this invention also provides a method for fabricating a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide, comprising the following steps:

[0069] Step S10: Set the topological transmission path on the substrate to divide the substrate into a type A topological photonic crystal region and a type B topological photonic crystal region;

[0070] Step S20: Set up a type A topological photonic crystal and a type B topological photonic crystal in the type A topological photonic crystal region and the type B topological photonic crystal region, respectively;

[0071] Step S30: A microfluidic channel is disposed on the substrate, wherein the microfluidic channel partially overlaps with the topology transmission path;

[0072] Step S40: A thin film is prepared on the side of the microfluidic channel away from the substrate. The thin film covers the area of ​​the substrate excluding the type A topological photonic crystal region and the type B topological photonic crystal region, and also covers the microfluidic channel.

[0073] Step S50: Set up an inlet seat and an outlet seat at both ends of the microfluidic channel, respectively;

[0074] Step S60: The bubble separation device, the piezoelectric ceramic micropump, the waste liquid tank and the substrate are placed on the housing. The bubble separation device and the piezoelectric ceramic micropump are connected through a pipe. The bubble separation device is connected to the liquid inlet seat and the waste liquid tank is connected to the liquid outlet seat to obtain the microfluidic sensing chip.

[0075] In some embodiments, the type A topological photonic crystal and the type B topological photonic crystal are disposed on the substrate by etching; the microfluidic channel is disposed on the substrate by etching. The thin film is disposed by bonding.

[0076] In some embodiments, step S10 specifically includes: the topological transmission path divides the substrate into upper and lower parts, the upper part is etched with a type A topological photonic crystal, and the lower part is etched with a type B topological photonic crystal. The type A topological photonic crystal is composed of multiple periodic topological photonic crystal cell units, and the type B topological photonic crystal is composed of multiple periodic topological photonic crystal cell units rotated 180° around the geometric center.

[0077] In some embodiments, step S40 specifically includes: making holes in the thin film at corresponding positions above the channel inlet and channel outlet etched on the substrate, and trimming the outer contour to match the outer contour of the substrate, and further removing the portion above the type A topological photonic crystal and type B topological photonic crystal except for the portion three lattice periods away from the microfluidic channel.

[0078] In some embodiments, the substrate, film, inlet seat, and outlet seat can be combined using one or more of the following methods: electrostatic adsorption, chemical bonding, and physical fixation; preferably, chemical bonding is used to combine the components.

[0079] In this embodiment, the thin film is chemically bonded to the substrate, closing the channel with the microfluidic channel. The inlet and outlet seats are aligned with the channel inlet and outlet, respectively, and are chemically bonded to the thin film.

[0080] In some embodiments, the housing is manufactured using photopolymer 3D printing or CNC machining of non-magnetic materials. This embodiment preferably employs 3D photopolymer printing technology and photosensitive resin materials to manufacture the outer shell.

[0081] In some implementations, the microfluidic sensing chip based on terahertz topological photonic crystal waveguide is used in microgravity environments.

[0082] In summary, this invention provides a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide and its fabrication method. The microfluidic sensing chip includes: a housing with a first receiving cavity, a second receiving cavity, and a substrate fixing platform disposed between the first receiving cavity and the second receiving cavity; a bubble separation device and a piezoelectric ceramic micropump, wherein the bubble separation device and the piezoelectric ceramic micropump are connected by a pipe and disposed within the first receiving cavity; a waste liquid tank disposed within the second receiving cavity; and a substrate disposed on the substrate fixing platform. An A is provided on the substrate. The system includes a type A topological photonic crystal, a type B topological photonic crystal, and a microfluidic channel. A topological transmission path is provided at the interface between the type A and type B topological photonic crystals. The microfluidic channel partially overlaps with the topological transmission path. A thin film is provided on the side of the microfluidic channel away from the housing, and a channel inlet is provided at one end of the microfluidic channel near the bubble separation device, and a channel outlet is provided at one end near the waste liquid tank. An inlet seat and an outlet seat are also provided, with the inlet seat located at the channel inlet and the outlet seat located at the channel outlet. This invention utilizes a microfluidic channel structure to reduce the absorption of terahertz electromagnetic waves by polar substances in the sample, thus achieving high detection sensitivity and low sample consumption. By applying the defects-immunizing and backscattering characteristics of topological photonic crystal waveguides, the yield rate and signal-to-noise ratio of sensor production can be improved. Furthermore, the characteristics of topological transmission edge states precisely confine electromagnetic wave energy within the microfluidic channel, enhancing sensor sensitivity. Additionally, a piezoelectric ceramic micropump housing enables high-precision sample feeding, simplifying usage and reducing integrated volume. A bubble separation device addresses the issue of increased injection pressure due to bubble suspension in microgravity environments, ensuring chip stability. The microfluidic sensor chip provided by this invention is a highly integrated sensor, reducing experimental operation difficulty and learning costs for astronauts. Therefore, this microfluidic sensor chip is suitable for experimental research in the confined environment of a space station.

[0083] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A microfluidic sensing chip based on a terahertz topological photonic crystal waveguide, characterized in that, include: The housing includes a first receiving cavity, a second receiving cavity, and a base fixing platform disposed between the first receiving cavity and the second receiving cavity; A bubble separation device and a piezoelectric ceramic micropump are provided, wherein the bubble separation device and the piezoelectric ceramic micropump are connected by a pipeline and are disposed in the first receiving cavity; A waste liquid tank is disposed within the second receiving cavity; A substrate is disposed on a fixed platform. The substrate is provided with a type A topological photonic crystal, a type B topological photonic crystal, and a microfluidic channel. A topological transport path is provided at the interface between the type A and type B topological photonic crystals. The microfluidic channel partially overlaps with the topological transport path. A thin film is provided on the side of the microfluidic channel away from the housing, and a channel inlet is provided at the end of the microfluidic channel near the bubble separation device, and a channel outlet is provided at the end near the waste liquid tank. The thin film covers the area of ​​the substrate excluding the type A and type B topological photonic crystal regions, and also covers the microfluidic channel. The membrane includes an inlet seat and an outlet seat, wherein the inlet seat is disposed at the inlet of the channel and the outlet seat is disposed at the outlet of the channel; the membrane has through holes corresponding to the inlet and outlet of the channel, and the inlet seat and the outlet seat are disposed on the side of the membrane away from the substrate and correspond to the through holes; The type A topological photonic crystal is composed of multiple periodic topological photonic crystal cell units, and the type B topological photonic crystal is composed of multiple periodic topological photonic crystal cell units rotated 180° around the geometric center; the topological photonic crystal cell units are provided with a first air hole and a second air hole; the microfluidic channel and the topological transport path have at least one lattice period overlap.

2. The microfluidic sensing chip based on a terahertz topological photonic crystal waveguide according to claim 1, characterized in that, The substrate material has a refractive index greater than 1.2 and an absorption coefficient less than 50 / mm at operating frequencies between 0.1THz and 10THz.

3. The microfluidic sensing chip based on a terahertz topological photonic crystal waveguide according to claim 1, characterized in that, The lattice constant of the unit cell of the topological photonic crystal is 1 μm to 1 mm.

4. The microfluidic sensing chip based on a terahertz topological photonic crystal waveguide according to claim 1, characterized in that, The topology transmission path is equipped with signal coupling ports at both the beginning and end.

5. The microfluidic sensing chip based on a terahertz topological photonic crystal waveguide according to claim 1, characterized in that, The piezoelectric ceramic micropump is equipped with a micropump electrical interface and a micropump liquid inlet.

6. The microfluidic sensing chip based on a terahertz topological photonic crystal waveguide according to claim 1, characterized in that, The waste liquid tank is provided with a waste liquid tank inlet and a waste liquid tank outlet; the waste liquid tank inlet is connected to the outlet seat; the inlet seat is connected to the bubble separation device.

7. A method for fabricating a microfluidic sensing chip based on a terahertz topological photonic crystal waveguide as described in any one of claims 1-6, characterized in that, Including the following steps: A topological transmission path is set on the substrate to divide the substrate into a type A topological photonic crystal region and a type B topological photonic crystal region; Type A topological photonic crystals and Type B topological photonic crystals are respectively disposed in the Type A topological photonic crystal region and the Type B topological photonic crystal region; A microfluidic channel is disposed on the substrate, and the microfluidic channel partially overlaps with the topology transmission path; A thin film is prepared on the side of the microfluidic channel away from the substrate. The thin film covers the regions of the substrate excluding the type A topological photonic crystal region and the type B topological photonic crystal region, as well as the microfluidic channel. An inlet seat and an outlet seat are respectively provided at both ends of the microfluidic channel; A bubble separation device, a piezoelectric ceramic micropump, a waste liquid tank, and the substrate are mounted on a housing. The bubble separation device and the piezoelectric ceramic micropump are connected through a pipe. The bubble separation device is connected to the liquid inlet seat, and the waste liquid tank is connected to the liquid outlet seat, thus obtaining a microfluidic sensing chip.

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