A two-dimensional material-based terahertz detection device and method

Abstract

The application provides a two-dimensional material terahertz detection device and method, and relates to the technical field of terahertz detection.The device comprises a two-dimensional material terahertz detector and a special amplification circuit arranged on a PCB board, wherein the output end of the two-dimensional material terahertz detector is connected with the input end of the special amplification circuit.The special amplification circuit comprises an instrument amplifier front end, a multi-stage amplification circuit, a filter circuit and a buffer output circuit which are electrically connected in sequence.The impedance adaptation between the detector and the amplifier is realized, the signal fidelity and noise performance are improved, and the compact integration between the detector and the amplifier is realized.

Description

Technical Field

[0001] This invention relates to the technical field of terahertz detection, and in particular to a terahertz detection device and method based on two-dimensional materials. Background Technology

[0002] Terahertz waves have important applications in imaging, communication and sensing. Two-dimensional material terahertz detectors have advantages such as room temperature operation, broadband response, strong light-matter interaction and compatibility with traditional planar processes. They are expected to become an important component of chip-level terahertz systems. These detectors are mostly based on photothermoelectric effect or grating voltage effect, can be self-powered, and have low power consumption and low noise characteristics.

[0003] In practical applications, two-dimensional material terahertz detectors face challenges in signal readout. On one hand, due to their micro-nano scale thickness and size, as well as their inherent response mechanism, the detectors can only generate weak electrical signals under terahertz irradiation, typically ranging from nA to μV in current or voltage. On the other hand, terahertz detectors based on two-dimensional materials generally exhibit low internal resistance, typically ranging from tens to thousands of ohms. This low resistance and weak output characteristic presents a significant challenge to circuit design for signal readout: the signal is highly susceptible to noise interference and easily attenuated due to impedance mismatch. To address the aforementioned issues, existing technologies typically employ a combination of a general-purpose preamplifier and a lock-in amplifier for measurement. While this approach can amplify the signal, it has significant limitations: transimpedance amplifiers, when configured for high gain, generally have high input resistance, resulting in significant current shunting when dealing with low-impedance detectors, leading to signal attenuation and a decrease in the signal-to-noise ratio; general-purpose voltage amplifiers have high input impedance, but their noise performance and gain are not optimized for the weak voltage signals of two-dimensional material terahertz detectors, and they are usually bulky and have low gain, making it difficult to meet system integration requirements. Summary of the Invention

[0004] To address the problems of impedance mismatch, poor signal fidelity, poor noise performance, and difficulty in compact integration of system circuits in the existing technologies, this invention proposes a terahertz detection device and method based on two-dimensional materials. This enables impedance matching between the detector and amplifier, improves signal fidelity and noise performance, and achieves compact integration between the detector and amplifier.

[0005] To achieve the above-mentioned technical effects, the technical solution of the present invention is as follows: A two-dimensional material terahertz detection device includes: a two-dimensional material terahertz detector and a dedicated amplification circuit disposed on a PCB board, wherein the output terminal of the two-dimensional material terahertz detector is connected to the input terminal of the dedicated amplification circuit; the dedicated amplification circuit includes an instrumentation amplifier front end, a multi-stage amplification circuit, a filter circuit and a buffer output circuit connected in sequence.

[0006] Preferably, the front end of the instrumentation amplifier is an instrumentation amplifier U1, the non-inverting input terminal of the instrumentation amplifier U1 is electrically connected to the drain electrode D of the two-dimensional material terahertz detector, the inverting input terminal of the instrumentation amplifier U1 is electrically connected to the source electrode of the two-dimensional material terahertz detector, and the output terminal of the instrumentation amplifier U1 is connected to the input terminal of a multi-stage amplifier circuit.

[0007] Preferably, the multi-stage amplifier circuit includes a second-stage amplifier circuit and a third-stage amplifier circuit. The output terminal of the instrumentation amplifier U1 is connected to the input terminal of the second-stage amplifier circuit, the output terminal of the second-stage amplifier circuit is connected to the input terminal of the third-stage amplifier circuit, and the output terminal of the third-stage amplifier circuit is connected to the input terminal of the filter circuit.

[0008] Preferably, the second-stage amplifier circuit includes a second operational amplifier U2, a first resistor R1, a second resistor R2, a third operational amplifier U3, a third resistor R3, a fourth resistor R4, and a first sliding rheostat RV1; The output terminal of the instrumentation amplifier U1 is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the inverting input terminal of the second operational amplifier U2. The output terminal of the second operational amplifier U2 and the other end of the second resistor R2 are connected together to the input terminal of the third stage amplifier circuit. The non-inverting input terminal of the second operational amplifier U2 is connected to both the inverting input terminal and the output terminal of the third operational amplifier U3. The non-inverting input terminal of the third operational amplifier U3 is connected to the sliding port of the first sliding rheostat RV1. The first fixed port of the first sliding rheostat RV1 is connected to one end of the third resistor R3. The second fixed port of the first sliding rheostat RV1 is connected to one end of the fourth resistor R4. The other end of the third resistor R3 is connected to the first external power supply, and the other end of the fourth resistor R4 is connected to the second external power supply.

[0009] Preferably, the third-stage amplifier circuit includes a fourth operational amplifier U4, a fifth resistor R5, a sixth resistor R6, and a second sliding rheostat RV2. The output terminal of the second operational amplifier U2 is connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 and the inverting input terminal of the fourth operational amplifier U4. The non-inverting input terminal of the fourth operational amplifier U4 is connected to a third external power supply, and the output terminal of the fourth operational amplifier U4 is connected to the input terminal of the filter circuit.

[0010] Preferably, the filtering circuit includes a first second-order filtering unit and a second second-order filtering unit. The output terminal of the fourth operational amplifier U4 is connected to the input terminal of the first second-order filtering unit, the output terminal of the first second-order filtering unit is connected to the input terminal of the second second-order filtering unit, and the output terminal of the second second-order filtering unit is connected to the input terminal of the buffer output circuit.

[0011] Preferably, the first second-order filter unit includes a fifth operational amplifier U5, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, and a second capacitor C2; The output terminal of the fourth operational amplifier U4 is connected to one end of the seventh resistor R7. The other end of the seventh resistor R7 is connected to one end of the first capacitor C1 and one end of the eighth resistor R8. The other end of the first capacitor C1 is connected to the inverting input terminal, the output terminal, and the input terminal of the second second-order filter unit of the fifth operational amplifier U5. The other end of the eighth resistor R8 is connected to one end of the second capacitor C2 and the non-inverting input terminal of the fifth operational amplifier U5. The other end of the second capacitor C2 is connected to the fourth external power supply.

[0012] Preferably, the second second-order filter unit includes a sixth operational amplifier U6, a ninth resistor R9, a tenth resistor R10, a third capacitor C3, and a fourth capacitor C4; The output terminal of the fifth operational amplifier U5 is connected to one end of the ninth resistor R9. The other end of the ninth resistor R9 is connected to one end of the third capacitor C3 and the tenth resistor R10. The other end of the third capacitor C3 is connected to the inverting input terminal, the output terminal, and the input terminal of the buffer output circuit of the sixth operational amplifier U6. The other end of the tenth resistor R10 is connected to the non-inverting input terminal of the sixth operational amplifier U6 and one end of the fourth capacitor C4. The other end of the fourth capacitor C4 is connected to the fourth external power supply.

[0013] Preferably, the buffer output circuit includes a seventh operational amplifier U7 and an eleventh resistor R11. The output terminal of the sixth operational amplifier U6 is connected to the positive input terminal of the seventh operational amplifier U7. The output terminal of the seventh operational amplifier U7 is connected to the inverting input terminal of the seventh operational amplifier U7 and one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is connected to the readout device.

[0014] This invention also proposes a terahertz detection method based on two-dimensional materials, comprising the following steps: S1. A two-dimensional material terahertz detector is used to receive terahertz waves and outputs a terahertz wave voltage signal to a dedicated amplifier circuit. The dedicated amplifier circuit includes an instrumentation amplifier front end, a multi-stage amplifier circuit, a filter circuit, and a buffer output circuit that are connected in sequence. S2. Receive the terahertz wave voltage signal using the front end of the instrumentation amplifier, perform preliminary amplification on the terahertz wave voltage signal, and output the instrumentation amplification signal; S3. Receive the amplified signal from the instrument using the multi-stage amplifier circuit, optimize the gain of the amplified signal from the instrument, and output the gain-optimized signal. S4. Receive the gain optimization signal using the filtering circuit, and output the filtered signal to the buffer output circuit; S5. Receive the filtered signal using the buffer output circuit and output a buffer signal adapted to the readout device.

[0015] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: This invention proposes a terahertz detection device and method based on two-dimensional materials. First, the terahertz detector transmits the detected terahertz wave voltage signal to a dedicated amplifier circuit. This dedicated amplifier circuit, designed for the low impedance and weak voltage output characteristics of the two-dimensional material terahertz detector, employs voltage amplification to avoid signal attenuation caused by current shunting when amplifying low-resistance sources using transimpedance amplification. Second, the instrumentation amplifier in the dedicated amplifier circuit ensures low noise performance, effectively reduces load effects, and provides sufficient input stage gain. Third, the multi-stage amplifier circuit in the dedicated amplifier circuit achieves high overall gain, while easily adjusting the gain and bandwidth to adapt to different two-dimensional material terahertz detectors and detection requirements. Finally, the filter circuit in the dedicated amplifier circuit filters and buffers the output circuit, effectively solving the impedance mismatch problem between the detector and amplifier, improving signal fidelity and noise performance, and achieving compact integration between the detector and amplifier. Attached Figure Description

[0016] Figure 1 This diagram illustrates the structure of a two-dimensional material terahertz detection device proposed in this embodiment of the invention. Figure 2 This is a top view of the two-dimensional material terahertz detector structure proposed in the embodiments of the present invention; Figure 3 This is a front view of the two-dimensional material terahertz detector structure proposed in this embodiment of the invention; Figure 4 This is a top view of the two-dimensional terahertz detector structure based on PPAC-structured graphene material proposed in this embodiment of the invention. Figure 5 This is a front view of the two-dimensional material terahertz detector structure based on PPAC-structured graphene material proposed in this embodiment of the invention. Figure 6 This diagram illustrates the structural principle of a two-dimensional material terahertz detection device proposed in this embodiment of the invention. Figure 7 This diagram shows the amplitude-frequency response curve of the dedicated amplifier circuit proposed in the embodiments of the present invention. Figure 8 The diagram shows a test comparison between the two-dimensional material terahertz detection device proposed in this embodiment of the invention and a transimpedance amplifier and a voltage amplifier. Figure 9 This is a flowchart illustrating a two-dimensional material terahertz detection method proposed in an embodiment of the present invention.

[0017] 1. Two-dimensional material terahertz detector; 111. Dielectric layer; 112. Substrate layer; 121. Drain electrode; 122. Source electrode; 123. Gate electrode; 130. Two-dimensional material layer; 2. Dedicated amplifier circuit; 21. Instrumentation amplifier front end; 22. Multi-stage amplifier circuit; 221. Second-stage amplifier circuit; 222. Third-stage amplifier circuit; 23. Filter circuit; 231. First second-order filter unit; 232. Second second-order filter unit; 24. Buffered output circuit. Detailed Implementation

[0018] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. It is understandable to those skilled in the art that some well-known details may be omitted from the accompanying drawings; The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Example 1 See Figure 1 This invention proposes a two-dimensional material terahertz detection device with high sensitivity and high integration, used for detecting terahertz wave signals. It is suitable for two-dimensional material terahertz detectors with low impedance and weak voltage output. The device includes: a two-dimensional material terahertz detector 1 and a dedicated amplification circuit 2 mounted on a PCB board. The output terminal of the two-dimensional material terahertz detector 1 is connected to the input terminal of the dedicated amplification circuit 2. The dedicated amplification circuit 2 includes an instrumentation amplifier front end 21, a multi-stage amplification circuit 22, a filter circuit 23, and a buffer output circuit 24 connected in sequence.

[0020] The two-dimensional material terahertz detector 1 is used to receive terahertz waves and convert the terahertz wave signal into a terahertz wave voltage signal. The dedicated amplifier circuit 2 is used to condition the terahertz wave voltage signal, amplify, filter, adjust the DC bias, and provide buffer isolation. The two-dimensional material terahertz detector 1 and the dedicated amplifier circuit 2 are integrated on the same PCB. This two-dimensional material terahertz detection device is compatible with common readout devices such as data acquisition cards and supports external gate voltage to control the electric field of the two-dimensional material terahertz detector 1.

[0021] See Figure 2and Figure 3 In this embodiment, the two-dimensional material terahertz detector 1 consists of, from bottom to top, a substrate layer 112, a dielectric layer 111, a drain electrode 121, a source electrode 122, an optional gate electrode 123, and a two-dimensional material layer 130. The two-dimensional material layer 130 contacts the electrode D and the electrode through van der Waals forces. The gate electrode 123 penetrates the dielectric layer 111 and contacts the substrate layer 112. By applying a gate voltage to the gate electrode 123, the carrier concentration or type of the two-dimensional material layer 130 can be changed using electric field modulation, thereby controlling the response parameters of the two-dimensional material terahertz detector 1. The drain electrode 121 and the source electrode 122 can be selected in antenna shapes such as butterfly to enhance the absorption of terahertz waves; or in electrode shapes such as interdigitated electrodes to effectively increase the electrode area and reduce interface impedance.

[0022] See Figure 4 and Figure 5 In this embodiment, the two-dimensional terahertz detector 1 can also be selected as a PPAC-structured graphene material. The PPAC-structured graphene-based two-dimensional terahertz detector 1 consists of, from bottom to top, an intrinsic silicon oxide substrate, a drain electrode D, a source electrode S, and a two-dimensional material layer based on the PPAC-structured graphene. The intrinsic silicon oxide substrate has a thickness of 500±10μm and a resistivity >20000Ω. The oxide layer thickness is 300±10 μm. The drain electrode D and source electrode S are obtained by sequentially depositing titanium (Ti) and gold (Au). The Ti layer acts as an adhesion layer, improving the contact between the Au layer and the substrate. The Ti layer is 10 nm thick, and the Au layer is 100 nm thick. The two-dimensional material layer based on PPAC-structured graphene is a monolayer graphene material prepared using chemical vapor deposition. The PPAC-structured graphene material is obtained through stamp transfer technology and photolithography patterning, including a complete graphene layer on the left and a disk-shaped PPAC graphene layer on the right. The two-dimensional terahertz detector 1 is finally subjected to thermal annealing, such as an argon flow rate of 450 sccm. 2.5 torr internal gas pressure, held at 350℃ for 2 hours to remove surface contaminants and residues, adjust the doping level of the graphene material, and improve contact with the substrate and electrodes. The two-dimensional material terahertz detector 1 can be packaged in TO (Transfer Optical) form. Die-attach adhesive is used to mount the two-dimensional material terahertz detector 1 onto the TO socket, which is then cured at 250℃ for 3 hours. Gold wire ball bonding is used to connect the electrodes of the two-dimensional material terahertz detector 1 to the pin pads of the TO socket. Intrinsic high-resistivity silicon wafers can be used as the TO package window material to filter visible light.

[0023] Existing terahertz detection schemes often simply combine detectors and general-purpose amplifiers as independent components, failing to address the collaborative design challenges at the system level between low impedance matching, high-fidelity amplification of weak signals, and compact integration. This makes it difficult to fully utilize the superior performance of two-dimensional material terahertz detectors in system-level applications. Therefore, this embodiment proposes a solution that integrates a low-internal-resistance, low-output two-dimensional material terahertz detector with a specially optimized low-noise, high-gain amplifier as a unified detection device, resulting in a two-dimensional material terahertz detection device belonging to the field of room-temperature terahertz technology. The device includes a two-dimensional material terahertz detector 1 and a dedicated amplifier circuit 2, both integrated on the same PCB board. The two-dimensional material terahertz detector uses graphene or other two-dimensional materials with a plasmon polaritonic cavity (PPAC) structure, and can achieve electric field modulation through a gate to receive terahertz radiation and generate a response voltage signal. The dedicated amplifier circuit 2 uses a low-noise, high-gain instrumentation amplifier as its front end, and sequentially includes an instrumentation amplifier front end 21, a multi-stage amplifier circuit 22, a filter circuit 23, and a buffered output circuit 24, featuring high input impedance, low noise, and adjustable gain characteristics. The dedicated amplifier circuit 2 architecture features a collaborative matching design tailored to the low impedance and weak signal characteristics of the two-dimensional material terahertz detector, effectively reducing signal attenuation and noise interference, and achieving high-fidelity signal amplification. This embodiment of the two-dimensional material terahertz detection device has a compact overall structure, is easy to integrate, and is compatible with common data acquisition equipment. Test results show that the noise equivalent power (NEP) and signal-to-noise ratio (SNR) of the device are significantly better than traditional transimpedance amplification and voltage amplification schemes, and it is also compact and lower in cost, making it suitable for high-sensitivity terahertz imaging, communication, and sensing systems.

[0024] Example 2 See Figure 6 This embodiment further explains the working principle of the dedicated amplifier circuit 2. In this embodiment, the electrodes of the two-dimensional material terahertz detector are connected to the reserved pads on the PCB by aluminum or gold wire bonding, thereby achieving electrical connection with the dedicated amplifier circuit 2. More preferably, the two-dimensional material device can be packaged in a transistor package (TO). The two-dimensional material terahertz detector 1 is mounted on the base of the TO socket, and the electrodes of the two-dimensional material terahertz detector 1 are bonded to the pads of the TO socket pins by gold wire bonding. An intrinsic high-resistivity silicon wafer can be used as the window of the TO package to filter visible light. The TO-packaged two-dimensional material terahertz detector and the dedicated amplifier circuit are integrated on the same PCB and connected to the input terminal of the instrumentation amplifier front end through the TO socket pins.

[0025] The dedicated amplifier circuit 2 includes an instrumentation amplifier front end 21, a multi-stage amplifier circuit 22, a filter circuit 23, and a buffer output circuit 24, which are connected in sequence. The instrumentation amplifier front end 21 is instrumentation amplifier U1. In this embodiment, instrumentation amplifier U1 of model AD8428 is selected, which has a fixed gain of 2000 V / V and a gain of 1.5 nV / Hz. 1 / 2 The instrumentation amplifier U1 features low input voltage noise, low gain drift of 5 ppm / ℃, low offset drift of 0.3 μV / ℃, common-mode rejection ratio of over 140 dB, and bandwidth of 3.5 MHz. The non-inverting input of U1 is electrically connected to the drain electrode D of the two-dimensional material terahertz detector 1, and the inverting input is electrically connected to the source electrode S of the two-dimensional material terahertz detector 1. Lead connections should be kept as short as possible. The output of U1 is connected to the input of the multi-stage amplifier circuit 22. On the PCB layout, no traces or other copper layers should be placed around the inverting input pin of U1 to minimize stray capacitance at the input.

[0026] The multi-stage amplifier circuit 22 includes a second-stage amplifier circuit 221 and a third-stage amplifier circuit 222. The output terminal of the instrumentation amplifier U1 is connected to the input terminal of the second-stage amplifier circuit 221, the output terminal of the second-stage amplifier circuit 221 is connected to the input terminal of the third-stage amplifier circuit 222, and the output terminal of the third-stage amplifier circuit 222 is connected to the input terminal of the filter circuit 23.

[0027] The second-stage amplifier circuit 221 includes a second operational amplifier U2, a first resistor R1, a second resistor R2, a third operational amplifier U3, a third resistor R3, a fourth resistor R4, and a first sliding rheostat RV1; The output terminal of the instrumentation amplifier U1 is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the inverting input terminal of the second operational amplifier U2. The output terminal of the second operational amplifier U2 and the other end of the second resistor R2 are connected together to the input terminal of the third stage amplifier circuit 222. The non-inverting input terminal of the second operational amplifier U2 is connected to the inverting input terminal and the output terminal of the third operational amplifier U3. The non-inverting input terminal of the third operational amplifier U3 is connected to the sliding port of the first sliding rheostat RV1. The first fixed port of the first sliding rheostat RV1 is connected to one end of the third resistor R3. The second fixed port of the first sliding rheostat RV1 is connected to one end of the fourth resistor R4. The other end of the third resistor R3 is connected to the first external power supply, and the other end of the fourth resistor R4 is connected to the second external power supply.

[0028] The second operational amplifier U2, the first resistor R1, and the second resistor R2 constitute the first inverting amplifier circuit. The third operational amplifier U3, the third resistor R3, the fourth resistor R4, and the first variable resistor RV1 constitute the bias voltage module. The inverting amplifier circuit is used to set the gain of the second-stage amplifier circuit, as shown by the formula G = R2 / R1. In a high-gain DC-coupled amplifier circuit, the output typically exhibits a large DC voltage offset. The bias voltage module is connected to the non-inverting input of the second operational amplifier U2, providing DC bias adjustment in the second-stage amplifier circuit to compensate for the output DC voltage offset. In the bias voltage module, R3, R4, and RV1 form a voltage divider; U4 forms a follower, providing buffering and reducing the impact of the voltage divider impedance on the inverting proportional amplifier circuit. The gain of the second-stage amplifier circuit is set to 5 V / V, R1=1 kΩ, R2=4.99 kΩ, R3=R4=100 kΩ, and RV1=200 kΩ.

[0029] The third-stage amplifier circuit 222 includes a fourth operational amplifier U4, a fifth resistor R5, a sixth resistor R6, and a second variable resistor RV2. The output terminal of the second operational amplifier U2 is connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 and the inverting input terminal of the fourth operational amplifier U4. The non-inverting input terminal of the fourth operational amplifier U4 is connected to a third external power supply, and the output terminal of the fourth operational amplifier U4 is connected to the input terminal of the filter circuit 23. The fourth operational amplifier U4, the fifth resistor R5, the sixth resistor R6, and the second variable resistor RV2 constitute a second inverting proportional amplifier circuit, which is used to fine-tune the overall gain after assembly and to compensate for component tolerances. The gain of the third-stage amplifier circuit is set to approximately 5 V / V, R5=R6=1 kΩ, and RV2=5 kΩ.

[0030] Here, both the second-stage amplifier circuit 221 and the third-stage amplifier circuit 222 use an inverting proportional amplifier circuit structure. The second-stage amplifier circuit 221 is used to increase the gain; the third-stage amplifier circuit 222 uses a sliding rheostat as a feedback resistor to fine-tune the overall gain after assembly and compensate for component tolerances. If DC coupling is used in each stage of the dedicated amplifier circuit 2, a bias voltage module consisting of a voltage divider and a follower can be connected to the inverting input terminal of the second-stage amplifier circuit 221 to adjust the DC bias of the dedicated amplifier circuit.

[0031] The filtering circuit 23, used to limit bandwidth and suppress noise while ensuring minimal signal waveform distortion, includes a first second-order filtering unit 231 and a second second-order filtering unit 232, with a cutoff frequency of 10 kHz. The output of the fourth operational amplifier U4 is connected to the input of the first second-order filtering unit 231, the output of the first second-order filtering unit 231 is connected to the input of the second second-order filtering unit, and the output of the second second-order filtering unit is connected to the input of the buffer output circuit 24. The cascaded first second-order filtering unit 231 and the second second-order filtering unit 232 constitute a fourth-order Bessel filter, used to limit the cutoff frequency to 10 kHz. The fourth-order Bessel filter provides... An 80 dB / dec roll-off is achieved while preserving the signal waveform to the greatest extent possible. The first second-order filter unit 231 includes a fifth operational amplifier U5, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, and a second capacitor C2. The output terminal of the fourth operational amplifier U4 is connected to one end of the seventh resistor R7. The other end of the seventh resistor R7 is connected to one end of the first capacitor C1 and one end of the eighth resistor R8. The other end of the first capacitor C1 is connected to the inverting input terminal, the output terminal, and the input terminal of the second second-order filter unit 232 of the fifth operational amplifier U5. The other end of the eighth resistor R8 is connected to one end of the second capacitor C2 and the non-inverting input terminal of the fifth operational amplifier U5. The other end of the second capacitor C2 is connected to the fourth external power supply. The second second-order filter unit 232 includes a sixth operational amplifier U6, a ninth resistor R9, a tenth resistor R10, a third capacitor C3, and a fourth capacitor C4; The output terminal of the fifth operational amplifier U5 is connected to one end of the ninth resistor R9. The other end of the ninth resistor R9 is connected to one end of the third capacitor C3 and the tenth resistor R10. The other end of the third capacitor C3 is connected to the inverting input terminal, the output terminal, and the input terminal of the buffer output circuit 24 of the sixth operational amplifier U6. The other end of the tenth resistor R10 is connected to the non-inverting input terminal of the sixth operational amplifier U6 and one end of the fourth capacitor C4. The other end of the fourth capacitor C4 is connected to the fourth external power supply.

[0032] Where R7=1.15kΩ, R8=2.55kΩ, R9=806Ω, R10=1.54kΩ, C1=10nF, C2=1.6nF, C3=11nF, and C4=9.1nF.

[0033] The buffer output circuit 24 includes a seventh operational amplifier U7 and an eleventh resistor R11. The output terminal of the sixth operational amplifier U6 is connected to the positive input terminal of the seventh operational amplifier U7. The output terminal of the seventh operational amplifier U7 is connected to the inverted input terminal of the seventh operational amplifier U7 and one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is connected to the readout device.

[0034] The seventh operational amplifier U7 forms a follower, providing low output impedance and high gain drive capability; the eleventh resistor R11 is used to set the output resistance and match the input impedance of readout devices such as data acquisition cards and lock-in amplifiers, R11=49.9kΩ.

[0035] In dedicated amplifier circuit 2, resistors R1-R11 use precision resistors with ±0.1% accuracy, and capacitors C1-C4 use precision capacitors with ±5% accuracy; the resistor accuracy is better than ±1%. The package uses 0603 or 0402 surface mount packages. U1-U7 use OPA2192 precision operational amplifiers, characterized by low offset voltage and low offset voltage temperature drift. The two-dimensional material terahertz detection device employs a compact PCB layout, effectively suppressing RF noise coupling. The overall gain of the dedicated amplifier circuit is set to 5 × 10⁻⁶. 4 V / V can amplify voltages in the μV range to the mV range, meeting the input requirements of most readout devices.

[0036] See Figure 7 , Figure 7 The figure shows the amplitude-frequency response curve of the dedicated amplifier circuit. Figure 7 The solid and dashed lines represent the fitted curves for gain and phase, respectively.

[0037] See Figure 8 , Figure 8 The image shows a comparison of terahertz wave photoelectric response test results using a two-dimensional material terahertz detector and a laboratory-grade transimpedance amplifier (FEMTO, DLPCA-200) and voltage amplifier (SRS, SR560). The same two-dimensional material terahertz detector was used in the tests. Figure 8 As shown, the detector element is based on graphene material and asymmetric interdigitated electrodes, with a resistance of only 5.6 Ω, demonstrating the applicability of this device in low-impedance two-dimensional material terahertz detectors. Using the same test conditions (2.52 THz continuous wave, 477 Hz optical chopper modulation, lock-in amplifier measurement), the photovoltage of this two-dimensional material terahertz detector was measured at different effective incident terahertz powers. The dashed lines represent the linear fit of the data, reflecting the responsivity of the detector element under different measurement configurations. The test results show that the two-dimensional material terahertz detection device proposed in this embodiment, compared with a two-dimensional material terahertz detector using a transimpedance amplifier (FEMTO, DLPCA-200), can avoid the signal attenuation problem caused by current shunting; the overall performance of the device is comparable to the configuration of a two-dimensional material terahertz detector and a voltage amplifier (SRS, SR560), and it has a smaller size and lower cost.

[0038] The terahertz detection device based on two-dimensional materials proposed in this invention also has the following advantages: 1. Coordinated Matching: The dedicated amplifier circuit is tailor-made for the low impedance and weak voltage output characteristics of two-dimensional material terahertz detectors. The dedicated amplifier circuit employs voltage amplification, avoiding signal attenuation caused by current shunting when amplifying low-impedance sources using transimpedance amplification. The low-noise, high-input-impedance, high-gain instrumentation amplifier front-end ensures low noise performance, effectively reduces load effects, and provides sufficient input stage gain, thereby reducing the requirements on subsequent amplifier stages. The multi-stage amplifier circuit achieves high overall gain while easily adjusting gain and bandwidth to adapt to different two-dimensional material terahertz detectors and detection requirements. High-precision resistors and capacitors, along with the gain adjustment module, ensure the accuracy of gain and bandwidth, providing better feedback on the performance of the two-dimensional material terahertz detector.

[0039] 2. System-level integration: The two-dimensional material terahertz detector and dedicated amplifier circuit are integrated on the same PCB, resulting in a compact size and overall performance comparable to laboratory-grade general-purpose voltage amplifiers, but at a lower cost. The short connection between the two-dimensional material terahertz detector and the instrumentation amplifier input reduces radio frequency interference, and the treatment that prohibits filling the area around the inverting input pin of the instrumentation amplifier with other copper layers reduces stray capacitance in the circuit. The device is compatible with common readout devices such as data acquisition cards and lock-in amplifiers.

[0040] Tests were conducted on the same two-dimensional material terahertz detector, such as the PPAC graphene detector. The overall setup was compared using a transimpedance amplifier (FEMTO, DLPCA-200) configuration (NEP: 23.0 μW / Hz). 1 / 2 (SNR: 35.9 dB) and voltage amplifier (SRS, SR560) configuration (NEP: 16.7 μW / Hz) 1 / 2 (SNR: 39.0 dB), exhibiting a lower NEP (8.47 μW / Hz). 1 / 2 ) and a higher signal-to-noise ratio (44.5 dB).

[0041] Example 3 See Figure 9 This embodiment proposes a terahertz detection method based on two-dimensional materials, including the following steps: S1. A two-dimensional material terahertz detector 1 is used to receive terahertz waves and outputs a terahertz wave voltage signal to a dedicated amplifier circuit 2. The dedicated amplifier circuit 2 includes an instrumentation amplifier front end 21, a multi-stage amplifier circuit 22, a filter circuit 23, and a buffer output circuit 24 that are connected in sequence. S2. Receive the terahertz wave voltage signal using the instrument amplifier front end 21, perform preliminary amplification on the terahertz wave voltage signal, and output the instrument amplification signal; S3. Receive the amplified instrument signal using the multi-stage amplifier circuit 22, optimize the gain of the amplified instrument signal, and output a gain-optimized signal; S4. The gain optimization signal is received by the filter circuit 23, and the filtered signal is output to the buffer output circuit 24. S5. The buffer output circuit 24 is used to receive the filtered signal and output a buffer signal adapted to the readout device.

[0042] In this embodiment, the terahertz detector first transmits the detected terahertz wave voltage signal to a dedicated amplifier circuit. This dedicated amplifier circuit, designed for the low impedance and weak voltage output characteristics of two-dimensional material terahertz detectors, employs voltage amplification to avoid signal attenuation caused by current shunting when amplifying low-resistance sources using transimpedance amplification. Secondly, the instrumentation amplifier in the dedicated amplifier circuit ensures low noise performance, effectively reduces load effects, and provides sufficient input stage gain. Then, the multi-stage amplifier circuit in the dedicated amplifier circuit achieves high overall gain, while easily adjusting the gain and bandwidth to adapt to different two-dimensional material terahertz detectors and detection requirements. Finally, the filter circuit in the dedicated amplifier circuit filters and buffers the output circuit, effectively solving the impedance mismatch problem between the detector and amplifier, improving signal fidelity and noise performance, and achieving compact integration between the detector and amplifier.

[0043] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A terahertz detection device based on two-dimensional materials, characterized in that, include: A two-dimensional material terahertz detector (1) and a dedicated amplifier circuit (2) are mounted on a PCB board. The output terminal of the two-dimensional material terahertz detector (1) is connected to the input terminal of the dedicated amplifier circuit (2). The dedicated amplifier circuit (2) includes an instrumentation amplifier front end (21), a multi-stage amplifier circuit (22), a filter circuit (23), and a buffer output circuit (24) that are connected in sequence. The front end (21) of the instrumentation amplifier is an instrumentation amplifier U1. The non-inverting input terminal of the instrumentation amplifier U1 is electrically connected to the drain electrode of the two-dimensional material terahertz detector (1). The inverting input terminal of the instrumentation amplifier U1 is electrically connected to the source electrode of the two-dimensional material terahertz detector (1). The output terminal of the instrumentation amplifier U1 is connected to the input terminal of the multi-stage amplifier circuit (22). The multi-stage amplifier circuit (22) includes a second-stage amplifier circuit (221) and a third-stage amplifier circuit (222). The output terminal of the instrumentation amplifier U1 is connected to the input terminal of the second-stage amplifier circuit (221), the output terminal of the second-stage amplifier circuit (221) is connected to the input terminal of the third-stage amplifier circuit (222), and the output terminal of the third-stage amplifier circuit (222) is connected to the input terminal of the filter circuit (23). The second stage amplifier circuit (221) includes a second operational amplifier U2, a first resistor R1, a second resistor R2, a third operational amplifier U3, a third resistor R3, a fourth resistor R4, and a first sliding rheostat RV1; The output terminal of the instrumentation amplifier U1 is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the inverting input terminal of the second operational amplifier U2. The output terminal of the second operational amplifier U2 and the other end of the second resistor R2 are connected together to the input terminal of the third stage amplifier circuit (222). The non-inverting input terminal of the second operational amplifier U2 is connected to the inverting input terminal and the output terminal of the third operational amplifier U3. The non-inverting input terminal of the third operational amplifier U3 is connected to the sliding port of the first sliding rheostat RV1. The first fixed port of the first sliding rheostat RV1 is connected to one end of the third resistor R3. The second fixed port of the first sliding rheostat RV1 is connected to one end of the fourth resistor R4. The other end of the third resistor R3 is connected to the first external power supply, and the other end of the fourth resistor R4 is connected to the second external power supply.

2. The terahertz detection device based on two-dimensional materials according to claim 1, characterized in that, The third-stage amplifier circuit (222) includes a fourth operational amplifier U4, a fifth resistor R5, a sixth resistor R6, and a second sliding rheostat RV2. The output terminal of the second operational amplifier U2 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 and the inverting input terminal of the fourth operational amplifier U4. The non-inverting input terminal of the fourth operational amplifier U4 is connected to a third external power supply. The output terminal of the fourth operational amplifier U4 is connected to the input terminal of the filter circuit (23).

3. The terahertz detection device based on two-dimensional materials according to claim 2, characterized in that, The filter circuit (23) includes a first second-order filter unit (231) and a second second-order filter unit (232). The output terminal of the fourth operational amplifier U4 is connected to the input terminal of the first second-order filter unit (231). The output terminal of the first second-order filter unit (231) is connected to the input terminal of the second second-order filter unit. The output terminal of the second second-order filter unit is connected to the input terminal of the buffer output circuit (24).

4. The terahertz detection device based on two-dimensional materials according to claim 3, characterized in that, The first second-order filter unit (231) includes a fifth operational amplifier U5, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, and a second capacitor C2; The output terminal of the fourth operational amplifier U4 is connected to one end of the seventh resistor R7. The other end of the seventh resistor R7 is connected to one end of the first capacitor C1 and one end of the eighth resistor R8. The other end of the first capacitor C1 is connected to the inverting input terminal, the output terminal, and the input terminal of the second second-order filter unit (232) of the fifth operational amplifier U5. The other end of the eighth resistor R8 is connected to one end of the second capacitor C2 and the positive input terminal of the fifth operational amplifier U5. The other end of the second capacitor C2 is connected to the fourth external power supply.

5. The terahertz detection device based on two-dimensional materials according to claim 4, characterized in that, The second second-order filter unit (232) includes a sixth operational amplifier U6, a ninth resistor R9, a tenth resistor R10, a third capacitor C3, and a fourth capacitor C4; The output terminal of the fifth operational amplifier U5 is connected to one end of the ninth resistor R9. The other end of the ninth resistor R9 is connected to one end of the third capacitor C3 and the tenth resistor R10. The other end of the third capacitor C3 is connected to the inverting input terminal, the output terminal and the input terminal of the buffer output circuit (24) of the sixth operational amplifier U6. The other end of the tenth resistor R10 is connected to the non-inverting input terminal of the sixth operational amplifier U6 and one end of the fourth capacitor C4. The other end of the fourth capacitor C4 is connected to the fourth external power supply.

6. The terahertz detection device based on two-dimensional materials according to claim 5, characterized in that, The buffer output circuit (24) includes a seventh operational amplifier U7 and an eleventh resistor R11. The output terminal of the sixth operational amplifier U6 is connected to the positive input terminal of the seventh operational amplifier U7. The output terminal of the seventh operational amplifier U7 is connected to the inverted input terminal of the seventh operational amplifier U7 and one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is connected to the readout device.

7. A method for terahertz detection based on two-dimensional materials, implemented using the two-dimensional material terahertz detection device as described in claim 1, characterized in that, Includes the following steps: S1. A two-dimensional material terahertz detector (1) is used to receive terahertz waves and outputs a terahertz wave voltage signal to a dedicated amplifier circuit (2). The dedicated amplifier circuit (2) includes an instrumentation amplifier front end (21), a multi-stage amplifier circuit (22), a filter circuit (23), and a buffer output circuit (24) connected in sequence. S2. Receive the terahertz wave voltage signal using the front end (21) of the instrument amplifier, amplify the terahertz wave voltage signal initially, and output the instrument amplified signal; S3. Receive the instrument amplified signal using the multi-stage amplifier circuit (22), optimize the gain of the instrument amplified signal, and output the gain-optimized signal; S4. The gain optimization signal is received by the filter circuit (23), and the filtered signal is output to the buffer output circuit (24). S5. Receive the filtered signal using the buffer output circuit (24) and output a buffer signal adapted to the readout device.

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