Integrated terahertz micro-fluidic sensor

Abstract

The utility model discloses an integrated terahertz micro-fluidic sensor, which belongs to the technical field of micro-fluidic sensors and comprises a transparent shell, a solute sensing part, a concentration sensing part and a translator, the transparent shell is arranged on the translator and can move on the translator in the linear direction. A micro-fluidic channel and a micro-pump channel are arranged in the transparent shell; one end of the microfluidic channel is open, and the other end of the microfluidic channel is sequentially communicated with the solute sensing part and the concentration sensing part and then is open; one end of the micropump channel is open, the other end of the micropump channel is communicated with the microfluidic channel, and a micropump is arranged in the micropump channel. According to the utility model, the THz solution measurement process is simplified, and the operability and reliability of the experiment are improved.

Description

Technical Field

[0001] This invention belongs to the field of microfluidic sensor technology, specifically relating to an integrated terahertz microfluidic sensor. Background Technology

[0002] Microfluidic chips, also known as lab-on-a-chip or micro-total analytical systems, operate on the principle of controlling fluids within tiny channels or chambers. By precisely controlling fluid flow and reactions, they achieve highly sensitive, accurate, and repeatable measurements and analyses. Microfluidic devices typically consist of microchannels, microvalves, micropumps, and sensors, which work together to ensure precise manipulation and measurement of fluids at the microscale. Microfluidic technology can drastically compress liquid volume, thereby reducing the interaction distance between water and THz (transient current flow), thus weakening the absorption of THz by water molecules. This technology holds broad application prospects and significant research value.

[0003] Currently, microfluidic chips are widely used in liquid detection. While conventional microfluidic chips can identify solutes, their structure and operating principles limit their application in concentration sensing, making it difficult to accurately detect concentration changes. Metasurface microfluidic chips, on the other hand, excel in concentration sensing, responding sensitively to concentration changes, but their design characteristics make them unsuitable for solute identification. Therefore, existing microfluidic chip technology has significant limitations in both key functions—solute identification and concentration sensing—and cannot simultaneously meet the needs of both. Utility Model Content

[0004] In view of this, the present invention provides an integrated terahertz microfluidic sensor that integrates a microfluidic sensor capable of measuring solute and concentration into one unit, eliminating the need for optical path adjustment, simplifying the THz solution measurement process, and improving the operability and reliability of the experiment.

[0005] This utility model is achieved through the following technical solution:

[0006] An integrated terahertz microfluidic sensor includes: a transparent housing, a solute sensing unit, a concentration sensing unit, and a translater;

[0007] The transparent shell is mounted on the translator and can move along a straight line on the translator;

[0008] The transparent shell contains a microfluidic channel and a micropump channel; one end of the microfluidic channel is open, and the other end is connected to the solute sensing unit and the concentration sensing unit in sequence before opening; one end of the micropump channel is open, and the other end is connected to the microfluidic channel, and a micropump is installed inside the micropump channel.

[0009] Furthermore, the bottom of the translator is provided with a slide groove, and the bottom of the transparent shell cooperates with the slide groove, so that the transparent shell can move back and forth along the slide groove; both sides of the transparent shell are provided with driving components, which are used to drive the transparent shell to move along the slide groove.

[0010] Furthermore, the driving component is an electric push rod, in which the push rod abuts against the transparent housing. When the electric push rod on one side of the transparent housing extends, the electric push rod on the other side shortens.

[0011] Furthermore, the micropump channel and the microfluidic channel are connected between the solute sensing unit and the concentration sensing unit.

[0012] Furthermore, the micropump includes a motor and a pump diaphragm; the micropump channel is located at one end of the largest side of the transparent housing, the pump diaphragm is attached to the micropump channel, and the motor is connected to the outside of the pump diaphragm.

[0013] Furthermore, the transparent shell has two through holes, each of which extends through the transparent shell from front to back, and the solute sensor and the concentration sensor are respectively located inside the through holes.

[0014] Furthermore, the concentration sensing unit includes a THz generating antenna, a THz detecting antenna, a latch-type metasurface, and a COC package.

[0015] The COC encapsulation shell is plasma-bonded to the transparent outer shell. The COC encapsulation shell includes a COC front plate and a COC rear plate. The COC front plate and the COC rear plate are plasma-bonded together. The side of the COC front plate faces the side of the femtosecond laser.

[0016] The COC package contains a cavity I, which is connected to a microfluidic channel. A latch-type metasurface is located inside the cavity I and is photolithographically set on the COC back plate.

[0017] The THz generating antenna is located on the inner side of the front panel of the COC, and the THz detecting antenna is located on the inner side of the rear panel of the COC. The THz generating antenna and the THz detecting antenna are positioned opposite each other.

[0018] Furthermore, the solute sensing unit includes a THz generating antenna, a THz detecting antenna, and a COC package.

[0019] The COC encapsulation shell is plasma-bonded to the transparent outer shell. The COC encapsulation shell includes a COC front plate and a COC rear plate. The COC front plate and the COC rear plate are plasma-bonded together. The side of the COC front plate faces the side of the femtosecond laser.

[0020] The COC package contains a cavity II, which is connected to a microfluidic channel. The THz generating antenna is located on the inner side of the front panel of the COC, and the THz detecting antenna is located on the inner side of the rear panel of the COC. The THz generating antenna and the THz detecting antenna are positioned opposite each other.

[0021] Furthermore, both the THz generating antenna and the THz detecting antenna include a semiconductor substrate and a metal electrode, respectively;

[0022] Semiconductor substrates are disposed one-to-one on the front plate and the back plate of COC. The metal electrodes include metal rings and metal strips. The metal rings are disposed on the corresponding semiconductor substrates. A notch is provided on the metal rings. The metal strips extend into the notch and form a slit with the metal rings.

[0023] Furthermore, the semiconductor substrate is a single-layer LT-GaAs thin film.

[0024] Beneficial effects:

[0025] (1) The present invention provides an integrated terahertz microfluidic sensor that integrates a solute sensing unit and a concentration sensing unit. On the one hand, when it is necessary to detect both solute and concentration at the same time, it is only necessary to move the transparent shell along the translator to align the solute sensing unit and the concentration sensing unit with the femtosecond laser, without having to adjust the optical path of the femtosecond laser. On the other hand, the solute sensing unit and the concentration sensing unit share a microfluidic channel, eliminating the need for manual diversion or separate injection of solution, so that the two experiments can be completed together, simplifying the THz solution measurement process and improving the convenience, operability and reliability of the measurement.

[0026] (2) The present invention is also provided with a driving component. By controlling the driving component to drive the movement of the transparent shell, the movement of the transparent shell is automated, and the rapid adjustment for different measurement purposes is achieved, further simplifying the measurement process of THz solution.

[0027] (3) The micropump channel and the microfluidic channel of this utility model are connected between the solute sensing section and the concentration sensing section, which can make the solution flowing into the solute sensing section and the concentration sensing section more uniform.

[0028] (4) This utility model uses a motor to drive the pump membrane to vibrate, which can precisely control the inflow and outflow of liquid, ensuring that the flow of liquid in the microfluidic channel is stable and controllable.

[0029] (5) This invention employs a latch-type metasurface, which can significantly enhance the interaction between the THz signal and liquid molecules. The latch-type metasurface can modulate a THz signal of a specific frequency, improving the sensitivity to changes in liquid concentration, thereby achieving more accurate concentration detection.

[0030] (6) The COC encapsulation shell of this utility model uses COC material in the prior art, which has the characteristics of high transparency and good detection effect for terahertz.

[0031] (7) The slit structure formed by the metal ring and metal strip of this invention can enhance the intensity of the THz signal. This structure can effectively concentrate the electric field, improve the acceleration and directional migration efficiency of charge carriers, thereby generating a stronger THz signal, which is especially important for the detection of low-concentration liquids, and can improve the signal-to-noise ratio of the detection and ensure the accuracy of the detection results.

[0032] (8) The semiconductor substrate of this utility model adopts a single-layer LT-GaAs thin film, which has good sensing effect and is conducive to signal transmission. Attached Figure Description

[0033] Figure 1 For integrated terahertz microfluidic sensor structure Figure I ;

[0034] Figure 2 For integrated terahertz microfluidic sensor structure Figure II ;

[0035] Figure 3 Diagram of the transparent outer shell structure;

[0036] Figure 4 Diagram of the micropump channel structure;

[0037] Figure 5 This is a structural diagram of the solute sensing unit;

[0038] Figure 6 Flowchart for the formation of the solute sensor;

[0039] Figure 7 This is a magnified image of a metasurface unit under a microscope.

[0040] Figure 8 The COC terahertz transmittance spectrum;

[0041] Figure 9 This is a magnified microscope image of the antenna structure.

[0042] Figure 10 A schematic diagram illustrating the principle of generating THz using a photoconductive antenna;

[0043] Figure 11 The absorption spectrum of riboflavin solution measured by a common microfluidic chip;

[0044] Figure 12 The transmittance spectrum was measured for a metasurface microfluidic chip.

[0045] Figure 13 Flowchart for preparing a metasurface for a concentration sensor using photolithography;

[0046] Figure 14 This is a schematic diagram of the LT-GaAs thin film structure;

[0047] Figure 15 This is a schematic diagram of LT-GaAs thin film fabrication.

[0048] Among them, 1-transparent shell, 2-solute sensing unit, 3-microfluidic channel, 4-micropump channel, 5-micropump, 6-THz generating antenna, 7-THz detection antenna, 8-concentration sensing unit, 9-translator, 10-drive unit, 11-latch-type metasurface, 100-liquid inlet, 101-liquid outlet I, 102-liquid outlet II. Detailed Implementation

[0049] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] Example 1:

[0051] This embodiment provides an integrated terahertz microfluidic sensor, see appendix. Figure 1-3 It includes: a transparent shell 1, a solute sensing unit 2, a concentration sensing unit 8, and a translation device 9;

[0052] The transparent outer shell 1 is mounted on the translator 9 and can move along a straight line on the translator 9;

[0053] The transparent shell 1 is provided with a microfluidic channel 3 and a micropump 5 channel 4; one end of the microfluidic channel 3 is open, and the other end is connected to the solute sensing unit 2 and the concentration sensing unit 8 in sequence before opening; one end of the micropump 5 channel 4 is open, and the other end is connected to the microfluidic channel 3, and a micropump 5 is provided in the micropump 5 channel 4.

[0054] This embodiment provides an integrated terahertz microfluidic sensor that integrates a solute sensing unit 2 and a concentration sensing unit 8. On the one hand, when it is necessary to detect both solute and concentration simultaneously, it is only necessary to move the transparent shell 1 along the translation device 9 to align the solute sensing unit 2 and the concentration sensing unit 8 with the femtosecond laser, without having to adjust the optical path of the femtosecond laser. On the other hand, the solute sensing unit 2 and the concentration sensing unit 8 share a single microfluidic channel 3, eliminating the need for manual flow splitting or separate solution injection, allowing both experiments to be completed simultaneously. This simplifies the THz solution measurement process and improves the convenience, operability, and reliability of the measurement.

[0055] The bottom of the translation device 9 is provided with a sliding groove, and the bottom of the transparent shell 1 is engaged with the sliding groove, so that the transparent shell 1 can move back and forth along the sliding groove. Both sides of the transparent shell 1 are provided with driving components 10, which are used to drive the transparent shell 1 to move along the sliding groove. Furthermore, the driving component 10 can be an electric push rod, in which the push rod abuts against the transparent shell 1. When the electric push rod on one side of the transparent shell extends, the electric push rod on the other side shortens. By controlling the driving component 10 to drive the movement of the transparent shell 1, the movement of the transparent shell 1 is automated, and rapid adjustment for different measurement purposes is achieved, further simplifying the measurement process of THz solution.

[0056] Furthermore, the micropump 5 channel 4 and the microfluidic channel 3 are connected between the solute sensing unit 2 and the concentration sensing unit 8.

[0057] Furthermore, the opening end of the channel 4 of the micropump 5 is designated as the liquid inlet 100100, and the two ends of the microfluidic channel 3 are designated as liquid outlet I 101101 and liquid outlet II 102102, respectively. The liquid inlet 100100, liquid outlet I 101101, and liquid outlet II 102102 are all located on the top surface of the transparent shell 1, which facilitates connection to external pipelines. Furthermore, the liquid outlet I 101101 and liquid outlet II 102102 are located on both sides of the liquid inlet 100100.

[0058] The transparent outer shell 1 can be made of one of the following materials: polycarbonate (PC), cyclic olefin copolymer (COC), quartz glass, polystyrene, PDMS (polydimethylsiloxane), and plexiglass;

[0059] The micropump 5 includes a motor and a pump membrane; the micropump 5 channel 4 has an opening at one end located on the largest side of the transparent shell 1, the pump membrane is attached to the micropump 5 channel 4, the motor is connected to the outside of the pump membrane, the motor drives the pump membrane to vibrate, drawing the solution from the liquid inlet 100100 into the micropump 5 channel 4, and pumping it out into the microfluidic channel 3.

[0060] See appendix Figure 4 Along the direction from the liquid inlet 100100 to the point of connection with the microfluidic channel 3, the micropump 5 channel 4 includes a constant diameter section, an expansion section I, a circular pump chamber section and an expansion section II connected in sequence; the liquid delivery port adopts a valveless design.

[0061] Two through holes are provided on the transparent shell 1. Each through hole extends through the transparent shell 1 from front to back. The solute sensor 2 and the concentration sensor 8 are respectively disposed in the through holes.

[0062] See appendix Figure 5 and attached Figure 6The concentration sensing unit 8 includes a THz generating antenna 6, a THz detecting antenna 7, a latch type metasurface 1111, and a COC package.

[0063] The COC package shell is plasma-bonded to the transparent shell 1. The COC package shell includes a COC front plate and a COC rear plate; the COC front plate and the COC rear plate are plasma-bonded together; the side of the COC front plate faces the side of the femtosecond laser; a cavity I is provided inside the COC package shell, which is connected to the microfluidic channel 3; a latch-type metasurface 1111 is located inside the cavity I and is photolithographically set on the COC rear plate; a THz generating antenna 6 is located on the inner side of the COC front plate, and a THz detecting antenna 7 is located on the inner side of the COC rear plate, with the THz generating antenna 6 and the THz detecting antenna 7 positioned opposite each other; Appendix Figure 7 The shape of a latch-type metasurface 11;

[0064] The solute sensing unit 2 includes a THz generating antenna 6, a THz detecting antenna 7, and a COC encapsulation shell. The COC encapsulation shell is plasma-bonded to the transparent shell 1. The COC encapsulation shell includes a COC front plate and a COC rear plate. The COC front plate and the COC rear plate are plasma-bonded together. The side where the COC front plate is located faces the side where the femtosecond laser is located. A cavity II is provided inside the COC encapsulation shell. The cavity II is connected to the microfluidic channel 3. The THz generating antenna 6 is located on the inner side of the COC front plate, and the THz detecting antenna 7 is located on the inner side of the COC rear plate. The THz generating antenna 6 and the THz detecting antenna 7 are positioned opposite each other.

[0065] Both the concentration sensing unit 8 and the solute sensing unit 2 use COC packaging shells, see appendix. Figure 8 COC materials exhibit high transmittance for terahertz frequencies, low energy loss, and a transmittance exceeding 85%.

[0066] See appendix Figure 9 Both the THz generating antenna 6 and the THz detecting antenna 7 include a semiconductor substrate and a metal electrode, respectively. The semiconductor substrates are respectively disposed on the front plate and the back plate of COC. The metal electrode includes a metal ring and a metal strip. The metal ring is disposed on the corresponding semiconductor substrate. A notch is provided on the metal ring. The metal strip extends into the notch and forms a slit with the metal ring. Furthermore, the semiconductor substrate is a single-layer LT-GaAs thin film.

[0067] Overall working principle: The solution to be tested enters the channel 4 of the micropump 5 through the liquid inlet 100100. The micropump 5 pumps the liquid into the microfluidic channel 3, and the liquid is evenly distributed into the solute sensing unit 2 and the concentration sensing unit 8. When solute detection is required, the control drive unit 10 pushes the transparent shell 1 to align the solute sensing unit 2 with the femtosecond laser. When concentration detection is required, the control drive unit 10 pushes the transparent shell 1 to align the concentration sensing unit 8 with the femtosecond laser. The solution is discharged from the microfluidic channel 3 through the liquid outlet I 101101 and the liquid outlet II 102102, respectively.

[0068] Working principle of concentration sensing unit 8: The femtosecond laser generates THz waves after passing through THz generating antenna 6. After passing through the solution and through metasurface interaction, the light signal carrying liquid information is detected by THz detection antenna 7 and converted into an electrical signal, obtaining THz time domain and frequency domain signals. After computer processing, the THz absorption peak of the solution can be obtained. The concentration of the solution can be obtained based on the fingerprint spectrum characteristics of THz.

[0069] Working principle of solute sensing unit 2: The femtosecond laser generates a THz wave after passing through the THz generating antenna 6. After the THz wave passes through the solution, the light signal carrying the liquid information is detected by the THz detection antenna 7 and converted into an electrical signal, thus obtaining the THz time domain and frequency domain signals. After computer processing, the THz absorption peak of the solution can be obtained. Based on the THz fingerprint spectrum characteristics, the type of solute can be determined.

[0070] The principle of THz-liquid interaction: When a THz wave shines on a liquid surface, it interacts with the liquid molecules. Different concentrations of liquid molecules exhibit varying absorption, reflection, and transmission characteristics of THz waves. Therefore, by measuring the propagation characteristics of THz waves in a liquid (such as transmittance and reflectance), the concentration of the liquid can be indirectly inferred.

[0071] The principle of metasurface detection of liquid concentration: During the detection process, the metasurface, as the substrate or key component of the detection element, enhances the interaction between THz waves and liquid molecules. By designing a latch-shaped metasurface, efficient absorption of THz waves at specific frequencies can be achieved, thereby improving the sensitivity of the detection system to changes in liquid concentration.

[0072] The principle of THz wave generation by antenna 6: see appendix. Figure 10When a femtosecond laser (with photon energy greater than or equal to the band gap of the semiconductor substrate) irradiates a semiconductor substrate, the photoelectric effect occurs. During this process, electrons in the LT-GaAs semiconductor substrate absorb the laser energy and transition from the valence band to the conduction band, thereby instantaneously generating a large number of electron-hole pairs (photogenerated carriers) on the surface of the photoelectric semiconductor material. A square wave bias voltage is applied to the metal electrode to generate a bias electric field, and these photogenerated carriers (mainly electrons) begin to accelerate under the action of the applied bias electric field. On the surface of the photoelectric semiconductor material, the directional migration of these electrons forms a transient photocurrent. Since the acceleration of electrons is rapid and changes with time, this transient photocurrent will radiate electromagnetic waves. When the frequency of the square wave bias voltage is on the order of KHz, the THz generating antenna 6(6) can radiate THz waves.

[0073] The principle behind the THz detection antenna 7 is as follows: Under the influence of a bias electric field, excited charge carriers (especially electrons) accelerate. This acceleration leads to a rapid change in current, i.e., the generation of transient current. If a THz wave pulse electric field is incident on the surface of the photoconductive antenna, this electric field interacts with the charge carriers in the photoconductive gap. The THz wave electric field drives the charge carriers towards the two electrodes of the antenna, creating a potential difference. This potential difference can be detected by an external current indicator (such as an oscilloscope) to form an electrical signal, thereby enabling the detection of THz waves.

[0074] How to use:

[0075] Step 1: Connect the THz generating antenna 6 to the bias voltage, connect the liquid inlet 100 to the liquid to be tested with a hose, and connect the micro pump 5 to the power supply.

[0076] Step 2: Start micropump 5. The test solution is drawn into micropump 5 and then pumped out through the channel to microfluidic channel 3, where it enters concentration sensing unit 8 and solute sensing unit 2 respectively.

[0077] Step 3: Activate the electric push rod on the translation device 9 to move the transparent shell 1, so that the spot of the femtosecond laser coincides with the center of cavity II of the solute sensing unit 2, and start scanning to obtain the time domain signal of the liquid.

[0078] Step 4: Activate the electric push rod on the translation device 9 to move the transparent shell 1, so that the spot of the femtosecond laser coincides with the center of cavity I of the concentration sensing unit 8, and start scanning to obtain the liquid-metasurface transmission spectrum.

[0079] Step 5: Perform data processing on the time-domain signal and the liquid-metasurface transmission spectrum to obtain the solute types and concentrations in the solution.

[0080] Example 2:

[0081] Based on Embodiment 1, this embodiment provides a specific implementation. The transparent shell 1 is made of plexiglass and has dimensions of 80×40×4mm. The two through holes on the transparent shell 1 each have dimensions of 20mm×20mm×4mm. The circular pump chamber section of the micropump 5 channel 4 has a diameter of 20mm and a depth of 1.5mm. The depth of the micropump 5 channel 4 is 1.5mm. The equal-diameter section of the micropump 5 channel 4 is provided with a liquid delivery port I, which has a depth of 2mm and is connected to the liquid inlet 100100. The expansion section II of the micropump 5 channel 4 is provided with a liquid delivery port II, which has a depth of 2mm and is connected to the microfluidic channel 3. The pump membrane is attached to the surface of the micropump 5 channel 4 to ensure its overall airtightness and liquid flowability.

[0082] A 0.7 mm diameter drill bit is used to drill holes on the larger side of the transparent shell 1, which are connected to the corresponding microfluidic channel 3 and micropump 5 channel 4, forming a liquid inlet 100100, liquid outlet I 101101 and liquid outlet II 102102, with a diameter of 0.7 mm.

[0083] Both the COC front plate and the COC rear plate are 20mm×20mm×2mm in size. The inner side of the COC front plate has a groove of 20μm×10μm×25μm, and the inner side of the COC rear plate has a groove of 20μm×10μm×25μm. The grooves of the COC front plate and the COC rear plate are joined together to form the aforementioned cavity. The thickness of the cavity is 50μm (experiments have shown that this is the optimal thickness).

[0084] LT-GaAs thin films are bonded to the corresponding COC front or back plates; the COC front and back plates are bonded via oxygen plasma; the pump membrane is made of polydimethylsiloxane (PDMS) thin film;

[0085] See appendix Figure 11 and 12 Riboflavin solutions of 0.01 mg / ml, 0.05 mg / ml, and 0.1 mg / ml were pumped into solute sensing unit 2 and concentration sensing unit 8. The absorption peaks of the solutions were measured to be 1.03 THz and 1.17 THz. The THz transmittance spectrum of the metasurface showed a red shift as the concentration increased (red shift refers to the shift of the spectrum to lower frequencies), which is consistent with the expected results.

[0086] For further details, please see the appendix. Figure 13 The steps for preparing the latch-type metasurface 1111 are as follows:

[0087] Step 1: Spin-coat the photoresist AZ5214 onto the COC substrate while rotating the substrate during the coating process to control the thickness of the photoresist AZ5214 to approximately 1 μm.

[0088] Step 2: Place the mask on the surface of the photoresist AZ5214 and perform step-by-step exposure;

[0089] Step 3: Use a developer to dissolve and develop the exposed photoresist area. Then, perform low-temperature baking on the wafer to harden the remaining photoresist on the substrate surface.

[0090] Step 4: Deposit a layer of metal (usually gold) onto the surface at high temperature, so that the gold in the photoresist exposure area is plated onto the COC substrate with a thickness of about 800nm.

[0091] Step 5: Use high-temperature plasma to selectively remove the remaining photoresist, so that the excess metal is peeled off along with the photoresist, thereby completing the fabrication of the latch-type metasurface 11.

[0092] For further details, please see the appendix. Figure 14 and 15 The method for preparing LT-GaAs thin films is as follows:

[0093] The first step involves fabricating a four-layer epitaxial wafer structure. Specifically, a 2-inch semi-insulating gallium arsenide (SI-GaAs) substrate is used. First, an 80 nm thick GaAs buffer layer is grown at 580 °C. Then, a 200 nm thick AlAs sacrificial layer is grown at 550 °C. Next, a 2 μm thick LT-GaAs layer is grown at a low temperature of 200 °C. Finally, the wafer is annealed at 615 °C for 15 min. During the entire epitaxial wafer growth process, since the lattice constants of GaAs and AlAs are very close, direct growth of AlAs on GaAs is technically feasible. Furthermore, the high-temperature annealing stage after LT-GaAs crystal growth can improve the quality of the LT-GaAs crystal.

[0094] The second step involved immersing the epitaxial wafer structure in a 13.5% hydrochloric acid solution (by volume) and then heating it in a water bath at 73°C for 1 hour. Afterward, the test tube was shaken, and the epitaxial wafer structure separated into two distinct parts. One part deposited at the bottom of the tube, while the other part remained suspended in the hydrochloric acid solution, resulting in a monolayer LT-GaAs film.

[0095] If the PCA (THz generating antenna 6 and THz detecting antenna 7) is directly fabricated using existing LT-GaAs epitaxial wafers in THz sensor design and bonded to the front and back surfaces of the sensing region, the sensing effect will be very poor. This is because the multilayer structure of the epitaxial wafer causes multiple reflections of the THz wave between layers, resulting in multiple echoes in the detected THz time-domain spectrum, thus affecting the spectral resolution. Furthermore, LT-GaAs has a high dielectric constant, which leads to significant signal attenuation when THz waves pass through, thereby reducing the transmitted signal strength to some extent. A single-layer LT-GaAs thin film can be fabricated using the method described above.

[0096] In summary, the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An integrated terahertz microfluidic sensor, characterized in that, include: Transparent outer shell, solute sensing unit, concentration sensing unit, and translation device; The transparent shell is mounted on the translator and can move along a straight line on the translator; The transparent shell contains a microfluidic channel and a micropump channel; one end of the microfluidic channel is open, and the other end is connected to the solute sensing unit and the concentration sensing unit in sequence before opening; one end of the micropump channel is open, and the other end is connected to the microfluidic channel, and a micropump is installed inside the micropump channel.

2. The integrated terahertz microfluidic sensor as described in claim 1, characterized in that, The bottom of the translator is provided with a slide groove, and the bottom of the transparent shell cooperates with the slide groove, so that the transparent shell can move back and forth along the slide groove; both sides of the transparent shell are provided with driving components, which are used to drive the transparent shell to move along the slide groove.

3. The integrated terahertz microfluidic sensor as described in claim 2, characterized in that, The driving component is an electric push rod, in which the push rod abuts against the transparent shell. When the electric push rod on one side of the transparent shell extends, the electric push rod on the other side shortens.

4. An integrated terahertz microfluidic sensor as described in any one of claims 1-3, characterized in that, The micropump channel and the microfluidic channel are connected between the solute sensing unit and the concentration sensing unit.

5. An integrated terahertz microfluidic sensor as described in any one of claims 1-3, characterized in that, The micropump includes a motor and a pump diaphragm; the micropump channel is located at one end of the largest side of the transparent housing, the pump diaphragm is attached to the micropump channel, and the motor is connected to the outside of the pump diaphragm.

6. An integrated terahertz microfluidic sensor as described in any one of claims 1-3, characterized in that, Two through holes are provided on the transparent shell, each through the front and back of the transparent shell, and the solute sensor and the concentration sensor are respectively located in the through hole.

7. The integrated terahertz microfluidic sensor as described in claim 1, characterized in that, The concentration sensing unit includes a THz generating antenna, a THz detecting antenna, a latch-type metasurface, and a COC package. The COC encapsulation shell is plasma-bonded to the transparent outer shell. The COC encapsulation shell includes a COC front plate and a COC rear plate. The COC front plate and the COC rear plate are plasma-bonded together. The side of the COC front plate faces the side of the femtosecond laser. The COC package contains a cavity I, which is connected to a microfluidic channel. A latch-type metasurface is located inside the cavity I and is photolithographically set on the COC back plate. The THz generating antenna is located on the inner side of the front panel of the COC, and the THz detecting antenna is located on the inner side of the rear panel of the COC. The THz generating antenna and the THz detecting antenna are positioned opposite each other.

8. The integrated terahertz microfluidic sensor as described in claim 1, characterized in that, The solute sensing unit includes a THz generating antenna, a THz detecting antenna, and a COC package. The COC encapsulation shell is plasma-bonded to the transparent outer shell. The COC encapsulation shell includes a COC front plate and a COC rear plate. The COC front plate and the COC rear plate are plasma-bonded together. The side of the COC front plate faces the side of the femtosecond laser. The COC package contains a cavity II, which is connected to a microfluidic channel. The THz generating antenna is located on the inner side of the front panel of the COC, and the THz detecting antenna is located on the inner side of the rear panel of the COC. The THz generating antenna and the THz detecting antenna are positioned opposite each other.

9. An integrated terahertz microfluidic sensor as described in claim 7 or 8, characterized in that, Both the THz generating antenna and the THz detecting antenna include a semiconductor substrate and a metal electrode, respectively. Semiconductor substrates are disposed one-to-one on the front plate and the back plate of COC. The metal electrodes include metal rings and metal strips. The metal rings are disposed on the corresponding semiconductor substrates. A notch is provided on the metal rings. The metal strips extend into the notch and form a slit with the metal rings.

10. An integrated terahertz microfluidic sensor as described in claim 9, characterized in that, The semiconductor substrate is a single-layer LT-GaAs thin film.

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