Middle and far infrared detection device and detection method thereof

Abstract

The invention provides a middle and far infrared detection device and a detection method thereof. The middle and far infrared detection device comprises a laser emission module, a semiconductor structure, an infrared optical module and a signal processing module. The semiconductor structure is used for receiving a first optical signal and converting the first optical signal into a second optical signal; the semiconductor structure is also used for receiving an infrared light signal to be detected; the semiconductor structure generates optical phonons under the action of the infrared light signal, the optical phonons interact with excitons to enable the excitons to generate frequency shift so as to convert the first light signal into a third light signal, and the third light signal is different from the second light signal. The infrared optical module is used for controlling the propagation direction of the infrared light signal and focusing the infrared light signal, so that at least part of the laser spot of the first light signal coincides with the infrared spot of the infrared light signal in the semiconductor structure. And the signal processing module is used for determining the intensity of the infrared light signal. The integration level of the device can be improved.

Description

Technical Field

[0001] This application relates to the field of mid- and far-infrared light detection technology, specifically to a mid- and far-infrared detection device and its detection method. Background Technology

[0002] Mid- and far-infrared waves are infrared light with wavelengths greater than 3 micrometers in the electromagnetic spectrum, adjacent to near-infrared and microwaves. Compared to other bands, mid- and far-infrared waves possess unique properties, such as strong thermal radiation, high sensitivity to the rotational and vibrational energy levels of many molecules, and the ability to achieve high-resolution spectral analysis. Therefore, mid- and far-infrared waves show significant application prospects in various fields such as environmental monitoring, medical diagnosis, materials analysis, and infrared imaging.

[0003] Related studies have shown that optical microcavity structures can be used to detect mid- and far-infrared light. However, because optical microcavity structures require the utilization of total internal reflection, the structural units are often hundreds of micrometers in size, making it difficult to form arrays. The fabrication of optical microcavity structures, the high stability requirements of optical systems, and their complexity pose significant challenges to optical integration, limiting their scalability and integration capabilities to some extent. Since optical microcavity structures themselves cannot absorb mid- and far-infrared light, an absorbing medium needs to be added to their surface; the additional thermal contact process also slows down the response speed of the optical microcavity structure. Summary of the Invention

[0004] This application provides a mid-to-far infrared detection device, comprising:

[0005] The laser emitting module is used to emit the first optical signal;

[0006] A semiconductor structure is provided, wherein the semiconductor structure is used to receive a first optical signal and generate excitons under the action of the first optical signal to convert the first optical signal into a second optical signal; the semiconductor structure is also used to receive an infrared optical signal to be measured; the semiconductor structure generates optical phonons under the action of the infrared optical signal, the optical phonons interact with the excitons to cause the excitons to undergo frequency shift, so as to convert the first optical signal into a third optical signal, the third optical signal being different from the second optical signal;

[0007] An infrared optical module is used to control the propagation direction of the infrared light signal and focus the infrared light signal so that at least a portion of the laser spot of the first light signal coincides with the infrared spot of the infrared light signal in the semiconductor structure.

[0008] The signal processing module is used to acquire the first electrical signal after the second optical signal is converted and the second electrical signal after the third optical signal is converted, and to determine the intensity of the infrared light signal based on the first electrical signal and the second electrical signal.

[0009] In some embodiments, the mid- and far-infrared detection device further includes a first electrode and a second electrode disposed on the surface of the semiconductor structure. The first electrode and the second electrode are both electrically connected to the semiconductor structure to form a first photoelectric conversion structure. The first photoelectric conversion structure is electrically connected to the signal processing module. The second optical signal is converted into the first electrical signal through the first photoelectric conversion structure, and the third optical signal is converted into the second electrical signal through the first photoelectric conversion structure.

[0010] In some embodiments, the semiconductor structure is made of a light-transmitting material, and the signal processing module includes a second photoelectric conversion structure. The second photoelectric conversion structure is disposed on the side of the semiconductor structure away from the laser emitting module. The second photoelectric conversion structure is electrically connected to the signal processing module. The second optical signal is converted into the first electrical signal by the second photoelectric conversion structure, and the third optical signal is converted into the second electrical signal by the second photoelectric conversion structure.

[0011] In some embodiments, the second photoelectric conversion structure includes a photodiode, a photomultiplier tube, a phototransistor, a CCD image sensor, and a CMOS image sensor.

[0012] In some embodiments, the mid- and far-infrared detection device further includes a wavelength controller connected to the laser emission module, which is used to measure the wavelength of the current first optical signal and adjust the wavelength of the current first optical signal when the wavelength of the current first optical signal is not equal to the target wavelength of the first optical signal, wherein the target wavelength of the first optical signal is the wavelength required for the semiconductor structure to be excited to generate excitons.

[0013] In some embodiments, the mid- and far-infrared detection device further includes a laser power control module located between the laser emitting module and the semiconductor structure. The laser power control module is used to acquire the output power of the current first optical signal and adjust the output power of the current first optical signal when the output power of the current first optical signal is not equal to the target output power of the first optical signal. The target output power of the first optical signal is the output power required for the semiconductor structure to be excited to generate excitons.

[0014] In some embodiments, the laser power control module includes:

[0015] A photodetector is used to convert the first optical signal into a third electrical signal;

[0016] A laser servo, connected to the photodetector, is used to receive the third electrical signal and generate a control command when the output power of the first optical signal determined according to the third electrical signal is different from the target output power.

[0017] A laser modulator, located between the laser emitting module and the semiconductor structure, is signal-connected to the laser servo and is used to receive the modulation command and adjust the output power of the first optical signal according to the modulation command, so that the output power of the first optical signal is the same as the target output power of the first optical signal.

[0018] In some embodiments, the semiconductor structure is made of cuprous oxide, gallium arsenide, indium phosphide, silver oxide, tin oxide, two-dimensional materials, or perovskite materials.

[0019] In some embodiments, the semiconductor structure includes a substrate and a tapered micro / nanostructure covering the surface of the substrate, wherein the laser spot of the first optical signal on the semiconductor structure at least partially covers the tapered micro / nanostructure.

[0020] This application also provides a detection method for a mid-to-far infrared detection device, applied to the controller of the aforementioned mid-to-far infrared detection device, comprising:

[0021] The laser emitting module is controlled to emit a first optical signal toward the semiconductor structure, so that the semiconductor structure generates excitons under the action of the first optical signal, and the first optical signal is converted into a second optical signal;

[0022] The signal processing module is controlled to acquire the first electrical signal after the second optical signal is converted.

[0023] The signal processing module is controlled to acquire the second electrical signal after the conversion of the third optical signal, so that the signal processing module determines the intensity of the infrared light signal based on the first electrical signal and the second electrical signal; the third optical signal is obtained by the semiconductor structure generating optical phonons under the action of the infrared light signal and converting the first optical signal, at least a portion of the laser spot of the first optical signal coincides with the infrared spot of the infrared light signal in the semiconductor structure, and the third optical signal is different from the second optical signal.

[0024] The beneficial effects of this application include:

[0025] The mid-to-far infrared detection device provided in this embodiment detects infrared light signals by utilizing the characteristic of a semiconductor structure to generate optical phonons under the influence of infrared light signals. Specifically, a laser emitting module emits a first light signal to the semiconductor structure. When no infrared light is applied, the semiconductor structure absorbs the first light signal, generates excitons, and converts the first light signal into a second light signal. When infrared light is applied, the infrared light causes the semiconductor structure to generate optical phonons. The optical phonons interact with the excitons, causing a frequency shift in the excitons, thus converting the first light signal into a third light signal. Subsequently, the signal processing module converts the second light signal into a first electrical signal and the third light signal into a second electrical signal. The intensity of the infrared light signal can be determined based on the difference between the first and second electrical signals. Compared to conventional mid-to-far infrared detection devices that use optical microcavity structures, this application uses a semiconductor structure to construct the mid-to-far infrared detection device, which allows for array integration, resulting in higher integration density. Furthermore, the semiconductor structure can directly absorb mid-to-far infrared light without the need for an absorption medium, thus resulting in higher response speed and further higher detection efficiency.

[0026] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0028] Figure 1 The figure shows a comparison of the optical phonon absorption spectrum of a semiconductor structure (e.g., cuprous oxide crystal) and the signal intensity of the infrared light signal when an infrared light signal is applied to the semiconductor structure in the mid- and far-infrared spectral range.

[0029] Figure 2 The diagram shown is a structural schematic of a mid-to-far infrared detection device provided in an exemplary embodiment of this application;

[0030] Figure 3 The diagram shown is a structural schematic of a mid-to-far infrared detection device provided in another exemplary embodiment of this application;

[0031] Figure 4 The diagram shown is a structural schematic of a mid-to-far infrared detection device provided in another exemplary embodiment of this application;

[0032] Figure 5 The diagram shown is a structural schematic of a mid-to-far infrared detection device provided in another exemplary embodiment of this application;

[0033] Figure 6The image shown is a schematic diagram of the cone-shaped micro / nano structure on the surface of a semiconductor structure provided in an exemplary embodiment of this application under a microscope.

[0034] Figure 7 The figure shown is an experimental data diagram of a mid-to-far infrared detection device provided in an exemplary embodiment of this application;

[0035] Figure 8 The figure shown is an experimental data diagram of a mid-to-far infrared detection device provided in an exemplary embodiment of this application;

[0036] Figure 9 The figure shown is an experimental data diagram of a mid-to-far infrared detection device provided in an exemplary embodiment of this application.

[0037] In the figure: 1-Laser emitting module; 101-Laser spot; 2-Semiconductor structure; 21-Conical micro / nano structure; 3-Infrared optical module; 301-Infrared spot; 31-Infrared lens; 32-Visible-infrared dichroic mirror; 33-Parabolic mirror; 33a-Conical aperture; 4-Signal processing module; 41-Current amplifier; 42-Lock-in-the-loop amplifier; 5-First electrode; 6-Second electrode; 10-First photoelectric conversion structure; 20-Second photoelectric conversion structure; 7-Substrate; 8-CCD camera; 81-Signal processing circuit; 91-Wavelength controller; 92-Laser power control module; 921-Photodetector; 922-Laser servo; 923-Laser modulator; 941-First beam splitter; 942-Second beam splitter. Detailed Implementation

[0038] The mid- and far-infrared detection devices and their detection methods in the embodiments of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments can complement or combine with each other.

[0039] The inventors discovered through research that, for example Figure 1 As shown, when an infrared light signal is applied to a semiconductor structure (e.g., cuprous oxide crystal) in the mid-to-far infrared spectral range, the optical phonon absorption spectrum of the semiconductor structure shows a similar trend to that of the infrared light signal, that is, Figure 1 The curves showing changes in signal intensity and optical phonon absorption coefficient closely match. Therefore, this characteristic of semiconductor structures can be used to detect the signal intensity of mid- and far-infrared light.

[0040] Accordingly, embodiments of this application provide a mid-to-far infrared detection device, such as... Figure 2As shown, the system includes a laser emitting module 1, a semiconductor structure 2, an infrared optical module 3, and a signal processing module 4. The laser emitting module 1 emits a first optical signal. The semiconductor structure 2 receives the first optical signal and generates excitons under its influence, converting the first optical signal into a second optical signal. The semiconductor structure 2 also receives the infrared optical signal to be measured. Under the influence of the infrared optical signal, the semiconductor structure 2 generates optical phonons. These optical phonons interact with the excitons, causing a frequency shift and converting the first optical signal into a third optical signal, which is different from the second optical signal. The infrared optical module 3 controls the propagation direction of the infrared optical signal and focuses it so that at least a portion of the laser spot of the first optical signal coincides with the infrared spot of the infrared optical signal on the semiconductor structure 2. The signal processing module 4 acquires the first electrical signal after the conversion of the second optical signal and the second electrical signal after the conversion of the third optical signal, and determines the intensity of the infrared optical signal based on the first and second electrical signals.

[0041] The mid-to-far infrared detection device provided in this embodiment detects infrared light signals by utilizing the characteristic of a semiconductor structure 2 to generate optical phonons under the influence of infrared light signals. Specifically, the laser emitting module 1 emits a first light signal to the semiconductor structure 2. When no infrared light is applied, the semiconductor structure 2 absorbs the first light signal, generates excitons, and converts the first light signal into a second light signal. When infrared light is applied, the infrared light causes the semiconductor structure 2 to generate optical phonons. The optical phonons interact with the excitons, causing a frequency shift in the excitons, thus converting the first light signal into a third light signal. Subsequently, the signal processing module 4 converts the second light signal into a first electrical signal and the third light signal into a second electrical signal, thereby determining the intensity of the infrared light signal based on the difference between the first and second electrical signals. Compared to conventional mid-to-far infrared detection devices that use optical microcavity structures, this application uses a semiconductor structure 2 to construct the mid-to-far infrared detection device, which allows for array integration, resulting in higher integration density. Furthermore, the semiconductor structure 2 can directly absorb mid-to-far infrared light without the need for an absorption medium, thus resulting in higher response speed and further higher detection efficiency.

[0042] In some embodiments, the difference between the first electrical signal and the second electrical signal is proportional to the intensity of the infrared light signal; therefore, the magnitude of the infrared light signal can be reflected by the first and second electrical signals. Specifically, the energy range of mid-infrared and far-infrared light covers wavelengths of approximately 2.5 to 30 micrometers (mid-infrared) and 30 to 1000 micrometers (far-infrared), and its energy is sufficient to excite the optical phonon vibration modes within the semiconductor structure 2. When the infrared light signal irradiates the semiconductor structure 2, the photons of the infrared light signal are absorbed by the semiconductor structure, and the energy is transferred to the optical phonons in the lattice of the semiconductor structure, causing them to vibrate. This excites a large number of optical phonons in the semiconductor structure. The optical phonons interact with excitons, causing a frequency shift in the excitons, resulting in a signal change, thereby enabling the detection of the infrared signal.

[0043] In some embodiments, the semiconductor structure 2 can be formed using a single semiconductor wafer with a thickness ranging from 10 to 5000 μm. In some embodiments, the thickness of the single semiconductor wafer can be 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 1000 μm, 2000 μm, 3000 μm, 4000 μm, or 5000 μm. In one example, the thickness of the single semiconductor wafer is 1000 μm, and the thickness direction of the single semiconductor wafer is parallel to the direction from the laser emitting module 1 to the semiconductor structure 2.

[0044] In some embodiments, the semiconductor structure 2 is made of cuprous oxide (Cu₂O), gallium arsenide (GaAs), indium phosphide (InP), silver oxide (Ag₂O), tin dioxide (SnO₂), two-dimensional materials (e.g., graphene, hexagonal boron nitride, or other two-dimensional materials), or perovskite materials (ABX₃, where A and B are two cations, and X is an anion bonded to them). In one example, the semiconductor structure 2 is made of cuprous oxide. In band theory, cuprous oxide differs from most semiconductor materials in that its conduction band bottom and valence band top have the same parity. This means that the ground-state excitons of cuprous oxide cannot be excited by electric dipole transitions, but only by electric quadrupole transitions, resulting in an extremely narrow exciton linewidth (two to three orders of magnitude smaller than that of gallium arsenide, two-dimensional materials, etc.). In this detection method, the narrower the exciton linewidth, the higher the detection sensitivity. Using cuprous oxide single crystal as the semiconductor material can effectively improve the detection sensitivity by two to three orders of magnitude.

[0045] In some embodiments, such as Figure 2 As shown, the infrared spot 301 of the infrared light signal is located within the laser spot 101 of the first light signal. In other embodiments, the laser spot 101 of the first light signal and the infrared spot 301 of the infrared light signal completely overlap in the semiconductor structure 2 (not shown in the figure).

[0046] In some embodiments, such as Figure 3 As shown, the mid- and far-infrared detection device also includes a first electrode 5 and a second electrode 6 disposed on the surface of the semiconductor structure 2. The first electrode 5 and the second electrode 6 are both electrically connected to the semiconductor structure 2 to form a first photoelectric conversion structure 10. The first photoelectric conversion structure 10 is electrically connected to the signal processing module 4. The second optical signal is converted into a first electrical signal by the first photoelectric conversion structure 10, and the third optical signal is converted into a second electrical signal by the first photoelectric conversion structure 10.

[0047] In this embodiment, the first electrode 5, the second electrode 6, and the semiconductor structure 2 constitute a first photoelectric conversion structure 10. When the first optical signal is incident on the semiconductor structure 2, the semiconductor structure 2 absorbs the photons of the first optical signal, thereby converting the first optical signal. Under the action of an applied reverse bias voltage, electrons and holes move in opposite directions, thereby forming a photocurrent. Specifically, when no infrared light signal is applied, the semiconductor structure 2 converts the second optical signal into a first photocurrent signal, which is also a first electrical signal; when an infrared light signal is applied, the semiconductor structure 2 converts the third optical signal into a second photocurrent signal, which is also a second electrical signal.

[0048] In some embodiments, the first electrode 5 is the anode and the second electrode 6 is the cathode. In other embodiments, the first electrode 5 is the anode and the second electrode 6 is the cathode.

[0049] In some embodiments, the first electrode 5 may be made of aluminum (Al), gold (Au), silver (Ag), nickel (Ni), chromium (Cr), platinum (Pt), indium (In), tin (Sn), palladium (Pd), and copper (Cu). In one example, the first electrode 5 is made of gold (Au).

[0050] In some embodiments, the second electrode 6 may be made of aluminum (Al), gold (Au), silver (Ag), nickel (Ni), chromium (Cr), platinum (Pt), indium (In), tin (Sn), palladium (Pd), and copper (Cu). In one example, the second electrode 6 is made of gold (Au).

[0051] In some embodiments, the first electrode 5 may be disposed on the side of the semiconductor structure 2 facing the laser emitting module 1 or on the side of the semiconductor structure 2 facing away from the laser emitting module 1.

[0052] In some embodiments, the second electrode 6 may be disposed on the side of the semiconductor structure 2 facing the laser emitting module 1 or on the side of the semiconductor structure 2 facing away from the laser emitting module 1.

[0053] In some embodiments, such as Figure 3 As shown, the first electrode 5 and the second electrode 6 are both disposed on the side surface of the semiconductor structure 2 facing the laser emission module 1.

[0054] In some embodiments, both the first electrode 5 and the second electrode 6 are electrically connected to the photocurrent readout circuit to enable the photocurrent signal formed by the semiconductor structure 2 under optical signal excitation to be read through the photocurrent readout circuit.

[0055] In some embodiments, such as Figure 3 As shown, a substrate 7 is also provided on the side of the semiconductor structure 2 away from the laser emission module 1. When the thickness direction of the semiconductor structure 2 is vertical, that is, when the semiconductor structure 2 is laid flat, the substrate 7 can be used to support the semiconductor structure 2.

[0056] In some embodiments, such as Figure 4 As shown, the semiconductor structure 2 is made of a light-transmitting material. The mid- and far-infrared detection device also includes a second photoelectric conversion structure 20. The second photoelectric conversion structure 20 is located on the side of the semiconductor structure 2 away from the laser emission module 1. The second photoelectric conversion structure 20 is electrically connected to the signal processing module 4. The second optical signal is converted into a first electrical signal by the second photoelectric conversion structure 20, and the third optical signal is converted into a second electrical signal by the second photoelectric conversion structure 20.

[0057] In this embodiment, when no infrared light signal is applied, the first light signal is converted into a second light signal through the semiconductor structure 2. The second light signal then enters the second photoelectric conversion structure 20 and is converted into a first electrical signal. When an infrared light signal is applied, the first light signal is converted into a third light signal through the semiconductor structure 2. The third light signal then enters the second photoelectric conversion structure 20 and is converted into a second electrical signal. Therefore, the light signal can be converted into an electrical signal through the second photoelectric conversion structure 20, and the intensity of the infrared light signal can then be obtained.

[0058] In some embodiments, the second photoelectric conversion structure 20 includes a photodiode, a photomultiplier tube, a phototransistor, a CCD image sensor, and a CMOS image sensor. In some examples, the second photoelectric conversion structure 20 is a CCD image sensor. The CCD image sensor may be disposed in the CCD camera 8 and connected to the signal processing circuit 81 in the CCD camera 8.

[0059] In some embodiments, the signal processing module 4 determines a frequency domain signal reflecting the intensity distribution of infrared light signals based on the first electrical signal and the second electrical signal.

[0060] In some embodiments, the signal processing module 4 may include an oscilloscope and a frequency domain analysis unit (not shown in the figure). The oscilloscope is used to convert the first electrical signal and the second electrical signal into time-domain voltage signals. The frequency domain analysis unit is used to perform a fast Fourier transform on the time-domain voltage signal to a frequency domain signal, which can be used for frequency domain analysis.

[0061] In some embodiments, when the mid- and far-infrared detection device includes a first photoelectric conversion structure 10, the photocurrent readout circuit connected to the first electrode 5 and the second electrode 6 is electrically connected to the signal analysis and processing structure to convert the photocurrent signal into a frequency domain signal.

[0062] In some embodiments, when the mid- and far-infrared detection device includes a second photoelectric conversion structure 20, the signal processing circuit 81 connected to the second photoelectric conversion structure 20 is electrically connected to the signal analysis and processing structure, and is used to convert the photocurrent signal into a frequency domain signal.

[0063] In some embodiments, such as Figure 3 As shown, the mid- and far-infrared detection device also includes a wavelength controller, which is connected to the laser emission module 1. The wavelength controller is used to measure the wavelength of the current first optical signal and adjust the wavelength of the current first optical signal when the wavelength of the current first optical signal is not equal to the target wavelength of the first optical signal. The target wavelength of the first optical signal is the wavelength required for the semiconductor structure 2 to be excited to generate excitons.

[0064] In this embodiment, the wavelength of the first optical signal can be stabilized within the target range by a wavelength controller, avoiding large fluctuations in the first optical signal, reducing laser noise, and improving the accuracy of the detection results.

[0065] In some embodiments, the wavelength controller includes a wavelength meter 91 and a feedback control system (not shown). The wavelength meter 91 measures the wavelength of the current first optical signal, and the feedback control system adjusts the laser emission module 1 when the wavelength of the current first optical signal is not equal to the target wavelength of the first optical signal. In some embodiments, the wavelength meter 91 may be replaced by an ultra-stable cavity.

[0066] In some embodiments, such as Figure 3 As shown, the mid- and far-infrared detection device also includes a first beam splitter 941, which splits the first optical signal into beams and transmits a portion of the first optical signal to a wavelength meter for measuring the wavelength of the current first optical signal.

[0067] In some embodiments, the laser emitting module 1 can be a probe laser or a narrow linewidth laser diode. When the laser emitting module 1 is a narrow linewidth laser diode, it can be integrated with the semiconductor structure 2, the first electrode 5, and the second electrode 6.

[0068] In some embodiments, the infrared optical module 3 includes at least one parabolic mirror and / or at least one infrared lens and / or at least one visible-infrared dichroic mirror, disposed on one side of the semiconductor structure 2, for focusing infrared light signals and allowing infrared light signals to enter the semiconductor structure 2.

[0069] In some embodiments, such as Figure 3As shown, the infrared optical module 3 includes an infrared lens 31 and a visible-infrared dichroic mirror 32. The infrared light is first focused by the infrared lens 31, and then its direction is adjusted to be aligned with the direction of the first light signal incident on the surface of the semiconductor structure after passing through the visible-infrared dichroic mirror 32. This makes the infrared spot 301 formed by the infrared light signal on the semiconductor structure 2 within the range of the laser spot 101 formed by the first light signal on the semiconductor structure 2.

[0070] In some embodiments, such as Figure 5 As shown, the infrared optical module 3 includes a parabolic mirror 33 disposed between the laser emitting module 1 and the semiconductor structure 2. The parabolic mirror 33 has a conical aperture 33a, with the openings at opposite ends of the conical aperture 33a facing the laser emitting module 1 and the semiconductor structure 2, respectively. The conical aperture 33a allows a first light signal to pass through and enter the semiconductor structure 2. A parabolic mirror is an optical element with a parabolic reflective surface. In this embodiment, the conical aperture 33a allows the first light signal emitted by the laser emitting module 1 to pass smoothly through without being blocked. Simultaneously, the incident direction of the infrared light signal can be controlled by the first parabolic mirror 33, ensuring that the infrared light spot 301 formed on the semiconductor structure 2 by the infrared light signal is within the range of the laser light spot 101 formed on the semiconductor structure 2 by the first light signal. In some embodiments, the transmission path of the first light signal and the transmission path of the infrared light signal can be partially collinear and incident on the semiconductor structure 2 along the same path by utilizing the first parabolic mirror 33 with the conical aperture 33a.

[0071] In some embodiments, such as Figure 3 As shown, the mid- and far-infrared detection device also includes a laser power control module 92. The laser power control module 92 is located between the laser emission module 1 and the semiconductor structure 2. It is used to obtain the output power of the current first optical signal and adjust the output power of the current first optical signal when the output power of the current first optical signal is not equal to the target output power of the first optical signal. The target output power of the first optical signal is the output power required for the semiconductor structure 2 to be excited to generate excitons.

[0072] In this embodiment, by setting up a laser power control module 92 to regulate the output power of the laser, the output power of the first optical signal can be stabilized, laser noise can be reduced, and the accuracy of the detection results can be improved.

[0073] In some embodiments, the laser power control module 92 includes a photodetector 921, a laser servo 922, and a laser modulator 923. The photodetector 921 converts the first optical signal into a third electrical signal. The laser servo 922 is signal-connected to the photodetector 921 and receives the third electrical signal. When the output power of the first optical signal determined based on the third electrical signal is different from the target output power, it generates a control command. The laser modulator 923 is located between the laser emitting module 1 and the semiconductor structure 2, and is signal-connected to the laser servo 922. It receives the control command and adjusts the output power of the first optical signal according to the control command so that the output power of the first optical signal is the same as the target output power of the first optical signal.

[0074] In this embodiment, the output power of the laser can be stably adjusted by the photodetector 921, the laser servo 922, and the laser modulator 923.

[0075] In some embodiments, the mid- and far-infrared detection device further includes a second beam splitter 942, which is used to split the first optical signal after passing through the laser modulator 923 and send it into the photodetector 921 for photoelectric conversion.

[0076] In some embodiments, the laser modulator 923 includes at least one of a laser attenuator, an electro-optic modulator, and an acousto-optic modulator.

[0077] In some embodiments, such as Figure 6 As shown, the semiconductor structure 2 includes a substrate (not shown) and a cone-shaped micro / nano structure 21 covering the surface of the substrate. The laser spot of the first optical signal on the semiconductor structure 2 at least partially covers the cone-shaped micro / nano structure 21.

[0078] In this embodiment, a tapered micro / nano structure 21 is provided on the surface of the semiconductor structure 2, which increases the surface area of ​​the semiconductor structure 2, meaning that more photons can be absorbed per unit area, thereby improving the photoelectric conversion efficiency. A smooth surface causes a large amount of incident light to be reflected back, while the tapered micro / nano structure 21 reduces reflection loss by disrupting the specular reflection conditions. In addition, the tapered micro / nano structure 21 can generate a local electric field enhancement effect, which helps to accelerate the carrier separation process and improve the photocurrent signal.

[0079] In some embodiments, the bottom surface size of the cone-shaped micro / nano structure 21 ranges from 1 to 2 μm.

[0080] It should be noted that, along the direction from the substrate of semiconductor structure 2 to the cone tip micro / nano structure 21, the cross-sectional area of ​​the cone tip micro / nano structure 21 gradually decreases.

[0081] In some embodiments, the substrate and the cone-shaped micro / nano structure 21 are an integral structure.

[0082] In some embodiments, the cone-shaped micro / nano structure can be formed by etching the semiconductor structure 2 in acidic and alkaline solutions. In one example, the semiconductor structure 2 is made of cuprous oxide. A cuprous oxide single crystal can be placed in a 0.2 mol / L hydrochloric acid (HCl) solution for 10 seconds, rinsed with deionized water, and its surface wiped with a lint-free cotton swab. The cuprous oxide single crystal can then be placed in a 1 mol / L ammonia (NH3·H2O) solution for 10 seconds, rinsed with deionized water, and its surface wiped with a lint-free cotton swab. This process is repeated three times. This etching process can also remove semiconductor surface defects, thereby improving photoelectric conversion efficiency.

[0083] In some embodiments, such as Figure 3 As shown, the signal processing module 4 also includes a current amplifier 41 and a lock-in amplifier 42. The current amplifier 41 can amplify the first electrical signal and the second electrical signal to enhance the strength of the electrical signal, which is beneficial for data reading. The lock-in amplifier 42 can extract signals of specific frequencies from complex noise environments to improve the signal-to-noise ratio.

[0084] Based on the same inventive concept, this application also provides a detection method for a mid-to-far infrared detection device, applied to the controller of the mid-to-far infrared detection device in the foregoing embodiments, comprising the following steps:

[0085] The laser emitting module 1 is controlled to emit a first optical signal to the semiconductor structure 2, so that the semiconductor structure generates excitons under the action of the first optical signal, and the first optical signal is converted into a second optical signal;

[0086] The control signal processing module 4 acquires the first electrical signal after the second optical signal is converted;

[0087] The control signal processing module 4 acquires the second electrical signal after the conversion of the third optical signal, so that the signal processing module 4 determines the intensity of the infrared light signal based on the first electrical signal and the second electrical signal; the third optical signal is obtained by the semiconductor structure 2 generating optical phonons under the action of the infrared light signal and converting the first optical signal; at least a portion of the laser spot 101 of the first optical signal coincides with the infrared spot 301 of the infrared light signal in the semiconductor structure 2; the third optical signal is different from the second optical signal.

[0088] In this embodiment, the intensity of the infrared light signal can be determined by acquiring a first electrical signal and a second electrical signal, and by analyzing and calculating the mathematical relationship between the first electrical signal, the second electrical signal, and the infrared light signal. This embodiment allows for real-time acquisition of the infrared light signal intensity; the method is simple and highly operable.

[0089] For ease of understanding, this application provides two specific embodiments of the mid- and far-infrared detection device and its detection method described in the foregoing embodiments as follows:

[0090] Example 1

[0091] The mid-to-far infrared detection device includes a laser emission module 1, a semiconductor structure 2, an infrared optical module 3, and a signal processing module 4. For example... Figure 3 As shown, the laser emitting module 1 includes a narrow-linewidth laser, which generates a first optical signal with a wavelength of 610 nm. The semiconductor structure 2 is designed as a 1 mm thick semiconductor wafer made of cuprous oxide. The infrared optical module 3 includes an infrared lens 31 and a visible-infrared dichroic mirror 32. The infrared lens 31 is used to collect and converge the infrared light signal; the visible-infrared dichroic mirror 32 is used to collimate the collected infrared light signal with the first optical signal. After the infrared light signal is incident on the semiconductor structure 2, the semiconductor structure 2 is excited to generate optical phonons.

[0092] The mid- and far-infrared detection device also includes a wavelength meter 91 and a feedback control system (not shown in the figure). The wavelength meter 91 is used to measure the current wavelength of the first optical signal. The frequency accuracy of the wavelength meter 91 is 600MHz. The feedback control system is specifically a PID feedback control system, which can stabilize the wavelength of the first optical signal at the target wavelength. The target wavelength of the first optical signal is the wavelength required for the semiconductor structure 2 to be excited to form excitons.

[0093] The mid- and far-infrared detection device also includes a photodetector 921, a laser servo 922, and a laser attenuator 923, which can be used to stabilize the output power of the first optical signal.

[0094] Combination Figure 4 As shown, the mid- and far-infrared detection device also includes a first electrode 5 and a second electrode 6 disposed on the surface of the semiconductor structure 2. The first electrode 5, the second electrode 6 and the semiconductor structure 2 together form a first photoelectric conversion structure 10. The first electrode 5 and the second electrode 6 are both made of gold. The thickness of the first electrode 5 and the second electrode 6 is 100 nm. The gap between the first electrode 5 and the second electrode 6 is 20 μm. The first electrode 5 and the second electrode 6 are externally connected to a voltage measuring device, a current amplifier 41 and a lock-in amplifier 42.

[0095] like Figure 7 The diagram shows the relationship between the wavelength of the first optical signal and the photocurrent signal in semiconductor structure 2 when no infrared light signal is applied. Figure 8 The image shows the mid-to-far-infrared absorption spectrum of the semiconductor structure when an infrared light signal is applied, indicating that mid-to-far-infrared light effectively excites semiconductor structure 2 to generate optical phonons. For example... Figure 9 The diagram shows the spectrum of the photocurrent signal change in semiconductor structure 2 after an infrared light signal is applied. It should be noted that the photocurrent signal without an applied infrared light signal is the background noise (see [link to diagram]). Figure 7Therefore, the curve in the figure reflects the intensity change of the infrared light signal.

[0096] Specifically, infrared light signals can be obtained by analyzing and processing photocurrent signals based on the following principles.

[0097] Under the influence of an applied infrared light signal, semiconductor structure 2 is excited to generate optical phonons, and the phonon density N of the optical phonons is... Phonon With infrared light signal I IR It is directly proportional to the light intensity:

[0098] N Phonon ∝I IR

[0099] Exciton peak shift ΔE due to exciton-phonon interaction Exciton With phonon density N Phonon Proportional:

[0100] ΔE Exciton ∝N Phonon

[0101] The change in photocurrent signal ΔI and the exciton peak shift ΔE Exciton Proportional:

[0102] ΔI∝ΔE Exciton

[0103] Therefore, the change in photocurrent signal is directly proportional to the intensity of infrared light signal, and can linearly reflect the magnitude of infrared light signal intensity.

[0104] Specifically:

[0105] ΔI=I(ω+δω)-I(ω)

[0106] In the above formula, ΔI is the change in photocurrent signal before and after applying infrared light signal, which is the difference between the second electrical signal and the first electrical signal; I(ω) is the photocurrent when the probe light frequency is ω, which is the first electrical signal; I(ω+δω) is the photocurrent after the δω frequency shift, which is the second electrical signal.

[0107] Specific detection methods may include the following steps:

[0108] Step S1: Control the laser emitting module 1 to emit a first optical signal to the semiconductor, so that the semiconductor structure 2 receives the first optical signal and converts it into a second optical signal; at the same time, the wavelength can be controlled within the target wavelength range by the wavelength controller.

[0109] Step S2: The control signal processing module 4 acquires the first electrical signal after the second optical signal is converted by the first photoelectric conversion structure 10.

[0110] Step S3: The control signal processing module 4 acquires the second electrical signal after the third optical signal is converted by the first photoelectric conversion structure 10, so that the signal processing module 4 determines the intensity of the infrared light signal based on the first electrical signal and the second electrical signal; the third optical signal is obtained by the semiconductor structure 2 generating optical phonons under the action of the infrared light signal and converting the first optical signal, the laser spot 101 of the first optical signal and the infrared spot 301 of the infrared light signal coincide in the semiconductor structure 2, and the third optical signal is different from the second optical signal.

[0111] Example 2

[0112] The difference between this embodiment and Embodiment 1 lies in the structure used to convert the optical signal into an electrical signal. Figure 4 As shown, in this embodiment, a second photoelectric conversion structure 20 is used for photoelectric conversion. The second photoelectric conversion structure 20 is a CCD image sensor and is located in the CCD camera 8.

[0113] The intensity of the infrared light signal can be deduced from the first and second electrical signals by using a CCD camera 8 (visible light imaging) to record the second and third light signals and convert them into the first and second electrical signals respectively.

[0114] Specifically, infrared light signals can be obtained by analyzing and processing photocurrent signals based on the following principles.

[0115] Under the influence of an applied infrared light signal, semiconductor structure 2 is excited to generate optical phonons, and the phonon density N of the optical phonons is... Phonon The intensity I of the infrared light signal IR Proportional:

[0116] N Phonon ∝I IR

[0117] Exciton peak shift ΔE due to exciton-phonon interaction Exciton With phonon density N Phonon Proportional:

[0118] ΔE Exciton ∝N Phonon

[0119] The change in light transmission intensity ΔT and the exciton peak shift ΔE Exciton Proportional:

[0120] ΔT∝ΔE Exciton

[0121] Therefore, the change in the intensity of the transmitted light is directly proportional to the intensity of the infrared light signal, and can linearly reflect the magnitude of the intensity of the infrared light signal.

[0122] Specifically:

[0123] ΔT=T(ω+δω)-T(ω)

[0124] In the above formula, ΔT is the change in the transmission intensity of the probe light before and after the infrared light signal is applied, which is the difference between the intensity of the third light signal and the intensity of the second light signal; T(ω) is the transmission intensity of the probe light when the frequency is ω, which is the intensity of the second light signal; T(ω+δω) is the transmission intensity of the probe light after the frequency shift of δω, which is the intensity of the third light signal.

[0125] Specific detection methods may include the following steps:

[0126] Step S1: Control the laser emitting module 1 to emit a first optical signal to the semiconductor, so that the semiconductor structure 2 receives the first optical signal and converts it into a second optical signal; at the same time, the wavelength can be controlled within the target wavelength range by the wavelength controller.

[0127] Step S2: The control signal processing module 4 acquires the first electrical signal after the second optical signal is converted by the second photoelectric conversion structure 20.

[0128] Step S3: The control signal processing module 4 acquires the second electrical signal after the third optical signal is converted by the second photoelectric conversion structure 20, so that the signal processing module 4 determines the intensity of the infrared light signal based on the first electrical signal and the second electrical signal; the third optical signal is obtained by the semiconductor structure 2 converting the first optical signal under the action of the infrared light signal, the laser spot 101 of the first optical signal and the infrared spot 301 of the infrared light signal coincide in the semiconductor structure 2, and the third optical signal is different from the second optical signal.

[0129] It should be noted that the dimensions of layers and regions may be exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be intermediate layers. Additionally, it is understood that when an element or layer is referred to as being "below" another element or layer, it can be directly below the other element, or there may be more than one intermediate layer or element. Furthermore, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Similar reference numerals throughout indicate similar elements.

[0130] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0131] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0132] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A mid-to-far infrared detection device, characterized in that, include: The laser emitting module is used to emit the first optical signal; A semiconductor structure is provided, wherein the semiconductor structure is used to receive a first optical signal and generate excitons under the action of the first optical signal to convert the first optical signal into a second optical signal; the semiconductor structure is also used to receive an infrared optical signal to be measured; the semiconductor structure generates optical phonons under the action of the infrared optical signal, the optical phonons interact with the excitons to cause the excitons to undergo frequency shift, so as to convert the first optical signal into a third optical signal, the third optical signal being different from the second optical signal; An infrared optical module is used to control the propagation direction of the infrared light signal and focus the infrared light signal so that at least a portion of the laser spot of the first light signal coincides with the infrared spot of the infrared light signal in the semiconductor structure. The signal processing module is used to acquire the first electrical signal after the second optical signal is converted and the second electrical signal after the third optical signal is converted, and to determine the intensity of the infrared light signal based on the first electrical signal and the second electrical signal.

2. The mid-to-far infrared detection device according to claim 1, characterized in that, The mid- and far-infrared detection device further includes a first electrode and a second electrode disposed on the surface of the semiconductor structure. The first electrode and the second electrode are both electrically connected to the semiconductor structure to form a first photoelectric conversion structure. The first photoelectric conversion structure is electrically connected to the signal processing module. The second optical signal is converted into the first electrical signal through the first photoelectric conversion structure, and the third optical signal is converted into the second electrical signal through the first photoelectric conversion structure.

3. The mid-to-far infrared detection device according to claim 1, characterized in that, The semiconductor structure is made of a light-transmitting material. The signal processing module includes a second photoelectric conversion structure, which is disposed on the side of the semiconductor structure away from the laser emitting module. The second photoelectric conversion structure is electrically connected to the signal processing module. The second optical signal is converted into the first electrical signal by the second photoelectric conversion structure, and the third optical signal is converted into the second electrical signal by the second photoelectric conversion structure.

4. The mid-to-far infrared detection device according to claim 3, characterized in that, The second photoelectric conversion structure includes a photodiode, a photomultiplier tube, a phototransistor, a CCD image sensor, and a CMOS image sensor.

5. The mid-to-far infrared detection device according to claim 1, characterized in that, The mid- and far-infrared detection device also includes a wavelength controller, which is connected to the laser emission module and is used to measure the wavelength of the current first optical signal and adjust the wavelength of the current first optical signal when the wavelength of the current first optical signal is not equal to the target wavelength of the first optical signal. The target wavelength of the first optical signal is the wavelength required for the semiconductor structure to be excited to generate excitons.

6. The mid-to-far infrared detection device according to claim 1, characterized in that, The mid- and far-infrared detection device further includes a laser power control module, which is located between the laser emission module and the semiconductor structure. The laser power control module is used to acquire the output power of the current first optical signal and adjust the output power of the current first optical signal when the output power of the current first optical signal is not equal to the target output power of the first optical signal. The target output power of the first optical signal is the output power required for the semiconductor structure to be excited to generate excitons.

7. The mid-to-far infrared detection device according to claim 6, characterized in that, The laser power control module includes: A photodetector is used to convert the first optical signal into a third electrical signal; A laser servo, connected to the photodetector, is used to receive the third electrical signal and generate a control command when the output power of the first optical signal determined according to the third electrical signal is different from the target output power. A laser modulator, located between the laser emitting module and the semiconductor structure, is signal-connected to the laser servo and is used to receive the modulation command and adjust the output power of the first optical signal according to the modulation command, so that the output power of the first optical signal is the same as the target output power of the first optical signal.

8. The mid-to-far infrared detection device according to claim 1, characterized in that, The semiconductor structure is made of materials including cuprous oxide, gallium arsenide, indium phosphide, silver oxide, tin oxide, two-dimensional materials, or perovskite materials.

9. The mid-to-far infrared detection device according to claim 1, characterized in that, The semiconductor structure includes a substrate and a tapered micro / nano structure covering the surface of the substrate, wherein the laser spot of the first optical signal on the semiconductor structure at least partially covers the tapered micro / nano structure.

10. A detection method for a mid-to-far infrared detection device, applied to the controller of the mid-to-far infrared detection device according to any one of claims 1 to 9, characterized in that, include: The laser emitting module is controlled to emit a first optical signal toward the semiconductor structure, so that the semiconductor structure generates excitons under the action of the first optical signal, and the first optical signal is converted into a second optical signal; The signal processing module is controlled to acquire the first electrical signal after the second optical signal is converted. The signal processing module is controlled to acquire the second electrical signal after the conversion of the third optical signal, so that the signal processing module determines the intensity of the infrared light signal based on the first electrical signal and the second electrical signal; the third optical signal is obtained by the semiconductor structure generating optical phonons under the action of the infrared light signal and converting the first optical signal, at least a portion of the laser spot of the first optical signal coincides with the infrared spot of the infrared light signal in the semiconductor structure, and the third optical signal is different from the second optical signal.

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