Infrared detection device and method based on cavity optical force system

Abstract

The application provides an infrared detection device and method based on a cavity optical force system, which aims to eliminate dark current and electrical noise in a traditional infrared detection process through an optical measurement method and further improve the accuracy of infrared detection by using a quantum enhancement effect of the cavity optical force system.The device comprises a thin film hetero-mechanical vibrator, an optical fiber, and a suspension structure arranged at the center of the thin film hetero-mechanical vibrator, wherein the top of the suspension structure is provided with external infrared radiation, and the optical fiber is arranged close to one end of the thin film hetero-mechanical vibrator to form a cavity optical force system with the thin film hetero-mechanical vibrator; the thin film hetero-mechanical vibrator serves as an infrared sensing unit, and the cavity optical force system serves as an infrared detection unit.The method has the characteristics of high sensitivity and low noise for infrared detection, and provides a new detection idea and mechanism for infrared detection.

Description

Technical Field

[0001] This invention relates to the fields of infrared detection, cavity optomechanics, and micro / nano resonators. Specifically, it relates to an infrared detection device and method based on a cavity optomechanical system. Background Technology

[0002] Traditional infrared detectors utilize the photoelectric or photothermal effects as their working mechanism to convert light signals into electrical signals. This method of electrical measurement suffers from problems such as high noise and the inability to eliminate dark current, which limits the detectivity. Optical measurement methods, on the other hand, avoid the shortcomings of electrical measurements and have the advantages of simplicity and high sensitivity.

[0003] Cavity optomechanical systems, as powerful tools for studying physical phenomena in the quantum world, possess ultra-high sensitivity and are widely used for the precise measurement of physical quantities such as force, displacement, mass, and acceleration. In cavity optomechanical detection systems, optical measurement noise (such as optical shot noise) decreases with increasing laser intensity, while measurement reaction noise increases with increasing laser intensity. This gives a minimum noise level achievable by classical measurement methods: the standard quantum limit, which is the ultimate limit of measurement accuracy achievable by classical systems. However, in cavity optomechanical precision measurement systems, this standard quantum limit can actually be surpassed through certain quantum effects, such as quantum squeezed states and schemes to circumvent quantum reaction. Therefore, the technique of improving detection accuracy using quantum effects in cavity optomechanical systems (quantum enhancement) can be extended into the field of infrared detection, thereby achieving high-sensitivity and high-performance infrared detection.

[0004] Based on this, the present invention provides an infrared detection device and method based on a cavity optical system, which utilizes the quantum-level detection performance of the cavity optical system to achieve highly sensitive infrared detection. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an infrared detection device and detection method based on a cavity photodynamic system.

[0006] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0007] An infrared detection device based on a cavity optomechanical system includes: a thin-film heterogeneous mechanical oscillator 2, an optical fiber 3 below the thin-film heterogeneous mechanical oscillator 2, a suspension structure at the center of the thin-film heterogeneous mechanical oscillator 2, external infrared radiation 1 above the suspension structure, and the optical fiber 3 facing the center of the suspension structure of the thin-film heterogeneous mechanical oscillator 2; a cavity optomechanical system 10 is formed between the end of the optical fiber 3 near the thin-film heterogeneous mechanical oscillator 2 and the thin-film heterogeneous mechanical oscillator 2.

[0008] The suspension structure undergoes up-and-down mechanical vibration after absorbing external infrared radiation 1, and the visible light band detection light 4 is transmitted through optical fiber 3 to the area below the center of the suspension structure of the thin film heterogeneous mechanical oscillator 2.

[0009] The thin-film heterogeneous mechanical oscillator 2 serves as the infrared sensing unit, and the cavity optical-mechanical system 10 serves as the infrared detection unit.

[0010] As a preferred method, when the infrared sensing unit is working, external infrared radiation irradiates the thin-film heterogeneous mechanical oscillator 2. The two-dimensional infrared absorbing material layer 7 absorbs the incident external infrared radiation 1 and converts the absorbed infrared radiation into heat. This causes the thin-film heterogeneous mechanical oscillator 2 to undergo mechanical vibration under heat, thereby causing a certain degree of shift in the resonant frequency, i.e., frequency shift. By detecting the frequency shift response of the thin-film heterogeneous mechanical oscillator 2 under infrared radiation of different wavelengths and intensities in real time, the relationship between infrared radiation and frequency shift can be established, thus realizing the detection of infrared radiation.

[0011] As a preferred method, when the infrared detection unit is working, the visible light detection light 4 is incident vertically below the center of the suspended structure of the thin-film heterogeneous mechanical oscillator 2 through the optical fiber 3 as the transmission carrier. At this time, part of the visible light detection light 4 is transmitted at the end of the optical fiber, and the other part is reflected at the end of the optical fiber. The transmitted detection light is reflected back when it encounters the thin-film heterogeneous mechanical oscillator 2 and returns along the original path. The detection light reflected at the end of the optical fiber 3 and the detection light reflected back from the thin-film heterogeneous mechanical oscillator 2 form an optical interference signal. Subsequently, the corresponding frequency shift information of the thin-film heterogeneous mechanical oscillator can be obtained by detecting the interference signal with a spectrometer.

[0012] As a preferred embodiment, the thin-film heterogeneous mechanical oscillator 2 is a square frame structure. The frame includes, from bottom to top, a Si layer 5, a Si3N4 layer 6 above the Si layer 5, and a two-dimensional infrared absorbing material layer 7 above the Si3N4 layer 6. The square frame structure is hollowed out in the middle, and a suspension structure is provided on the upper surface of the square frame structure. The suspension structure includes four tethers 8 and a central platform 9. The four tethers 8 are perpendicular to each other, and the ends of the four tethers 8 near the center are connected together through the central platform 9. The suspension structure undergoes up-and-down mechanical vibration after absorbing external infrared radiation.

[0013] As a preferred embodiment, the material of the two-dimensional infrared absorbing material layer 7 is selected from PtSe2 or PdSe2.

[0014] As a preferred embodiment, the central platform 9 is a star shape with four arc edges, and the intersection of two adjacent arc edges is connected to the end of the tether 8 near the central platform.

[0015] The present invention also provides a detection method for the infrared detection device based on the cavity photomechanical system, which is as follows:

[0016] Thin-film heterogeneous mechanical oscillator 2 serves as an infrared sensing unit, and cavity optomechanical system 10 serves as an infrared detection unit.

[0017] When the infrared sensing unit is working, external infrared radiation irradiates the thin-film heterogeneous mechanical oscillator 2. The two-dimensional infrared absorbing material layer 7 absorbs the incident external infrared radiation 1 and converts the absorbed infrared radiation into heat. This causes the thin-film heterogeneous mechanical oscillator 2 to vibrate mechanically under heat, thereby causing a certain degree of shift in the resonant frequency, i.e., frequency shift. By detecting the frequency shift response of the thin-film heterogeneous mechanical oscillator 2 under infrared radiation of different wavelengths and intensities in real time, the relationship between infrared radiation and frequency shift can be established, thus realizing the detection of infrared radiation.

[0018] When the infrared detection unit is working, the visible light detection light 4 is incident vertically below the center of the suspended structure of the thin-film heterogeneous mechanical oscillator 2 through the optical fiber 3 as the transmission carrier. At this time, part of the visible light detection light 4 is transmitted at the end of the optical fiber, and the other part is reflected at the end of the optical fiber. The transmitted detection light is reflected back when it encounters the thin-film heterogeneous mechanical oscillator 2 and returns along the original path. The detection light reflected at the end of the optical fiber 3 and the detection light reflected back from the thin-film heterogeneous mechanical oscillator 2 form an optical interference signal. The corresponding frequency shift information of the thin-film heterogeneous mechanical oscillator can be obtained by detecting the interference signal by a spectrometer.

[0019] The beneficial effects of this invention are as follows: the infrared sensing unit of this invention has a simple structure, high sensitivity, and compatibility with optical measurement methods; simultaneously, optical measurement can improve the detection accuracy of the infrared detection process; the introduction of the cavity photomechanical system further improves the infrared detection sensitivity through quantum enhancement effects. Therefore, the device of this invention has a simple structure, rapid response, and high infrared detection sensitivity; the detection method of this invention has high accuracy and avoids the electrical noise and dark current of traditional electrical measurements. In the future, the infrared sensing unit in the device of this invention can be further extended into other similar suspended structures, providing more new technical ideas and detection mechanisms for infrared detection technology. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall infrared detection device based on the cavity photomechanical system of the present invention;

[0021] Figure 2 This is a schematic diagram of the overall structure of the thin-film heterogeneous mechanical oscillator of the present invention;

[0022] Figure 3 This is a cross-sectional view of a thin-film heterogeneous mechanical oscillator.

[0023] Figure 4 A top view of a thin-film heterogeneous mechanical oscillator;

[0024] Figure 5This is a schematic diagram of the infrared detection device of the present invention.

[0025] 1 is external infrared radiation, 2 is thin-film heterogeneous mechanical oscillator, 3 is optical fiber, 4 is detection light in the visible light band, 5 is Si layer, 6 is Si3N4 layer, 7 is two-dimensional infrared absorbing material layer, 8 is tether, 9 is central platform, 10 is cavity optomechanical system; 41 is transmitted light, 42 is reflected light, and 43 is detection light reflected back by thin-film heterogeneous mechanical oscillator. Detailed Implementation

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] like Figure 1 As shown, this embodiment provides an infrared detection device based on a cavity optomechanical system, including: a thin-film heterogeneous mechanical oscillator 2, an optical fiber 3 below the thin-film heterogeneous mechanical oscillator 2, a suspension structure at the center of the thin-film heterogeneous mechanical oscillator 2, external infrared radiation 1 above the suspension structure, and the optical fiber 3 facing the center of the suspension structure of the thin-film heterogeneous mechanical oscillator 2; a cavity optomechanical system 10 is formed between the end of the optical fiber 3 near the thin-film heterogeneous mechanical oscillator 2 and the thin-film heterogeneous mechanical oscillator 2.

[0028] The suspension structure undergoes up-and-down mechanical vibration after absorbing external infrared radiation 1, and the visible light band detection light 4 is transmitted through optical fiber 3 to the area below the center of the suspension structure of the thin film heterogeneous mechanical oscillator 2.

[0029] The thin-film heterogeneous mechanical oscillator 2 serves as the infrared sensing unit, and the cavity optical-mechanical system 10 serves as the infrared detection unit.

[0030] When the infrared sensing unit is working, external infrared radiation irradiates the thin-film heterogeneous mechanical oscillator 2. The two-dimensional infrared absorbing material layer 7 absorbs the incident external infrared radiation 1 and converts the absorbed infrared radiation into heat. This causes the thin-film heterogeneous mechanical oscillator 2 to vibrate mechanically under heat, thereby causing a certain degree of shift in the resonant frequency, i.e., frequency shift. By detecting the frequency shift response of the thin-film heterogeneous mechanical oscillator 2 under infrared radiation of different wavelengths and intensities in real time, the relationship between infrared radiation and frequency shift can be established, thus enabling the detection of infrared radiation.

[0031] When the infrared detection unit is working, the visible light detection light 4 is incident vertically below the center of the suspended structure of the thin-film heterogeneous mechanical oscillator 2 through the optical fiber 3 as the transmission carrier. At this time, part of the visible light detection light 4 is transmitted at the end of the optical fiber, and the other part is reflected at the end of the optical fiber. The transmitted detection light is reflected back when it encounters the thin-film heterogeneous mechanical oscillator 2 and returns along the original path. The detection light reflected at the end of the optical fiber 3 and the detection light reflected back from the thin-film heterogeneous mechanical oscillator 2 form an optical interference signal. The corresponding frequency shift information of the thin-film heterogeneous mechanical oscillator can be obtained by detecting the interference signal by a spectrometer.

[0032] like Figure 2 and Figure 3 As shown, the thin-film heterogeneous mechanical oscillator 2 has a square frame structure. The frame includes, from bottom to top, a Si layer 5, a Si3N4 layer 6 above the Si layer 5, and a two-dimensional infrared absorbing material layer 7 above the Si3N4 layer 6. The square frame structure is hollow in the middle, and a suspension structure is provided on the upper surface of the square frame structure. The suspension structure includes four tethers 8 and a central platform 9. The four tethers 8 are perpendicular to each other, and the ends of the four tethers 8 near the center are connected together through the central platform 9. The suspension structure undergoes up-and-down mechanical vibration after absorbing external infrared radiation.

[0033] Preferably, the material of the two-dimensional infrared absorbing material layer 7 is selected from PtSe2 and PdSe2.

[0034] like Figure 4 As shown, the central platform 9 is a star shape with four arc edges, and the intersection of two adjacent arc edges is connected to the end of the tether 8 near the central platform.

[0035] like Figure 5 As shown, this embodiment also provides a detection method for the infrared detection device based on the cavity optical system, which is as follows:

[0036] Thin-film heterogeneous mechanical oscillator 2 serves as an infrared sensing unit, and cavity optomechanical system 10 serves as an infrared detection unit.

[0037] When the infrared sensing unit is working, external infrared radiation irradiates the thin-film heterogeneous mechanical oscillator 2. The two-dimensional infrared absorbing material layer 7 absorbs the incident external infrared radiation 1 and converts the absorbed infrared radiation into heat. This causes the thin-film heterogeneous mechanical oscillator 2 to vibrate mechanically under heat, thereby causing a certain degree of shift in the resonant frequency, i.e., frequency shift. By detecting the frequency shift response of the thin-film heterogeneous mechanical oscillator 2 under infrared radiation of different wavelengths and intensities in real time, the relationship between infrared radiation and frequency shift can be established, thus realizing the detection of infrared radiation.

[0038] Figure 5In the diagram, 41 represents transmitted light, 42 represents reflected light, and 43 represents probe light reflected back by the thin-film heterogeneous mechanical oscillator.

[0039] When the infrared detection unit is working, the visible light detection light 4 is incident vertically below the center of the suspended structure of the thin-film heterogeneous mechanical oscillator 2 through the optical fiber 3 as the transmission carrier. At this time, part of the visible light detection light 4 is transmitted at the end of the optical fiber, and the other part is reflected at the end of the optical fiber. The transmitted detection light is reflected back when it encounters the thin-film heterogeneous mechanical oscillator 2 and returns along the original path. The detection light reflected at the end of the optical fiber 3 and the detection light reflected back from the thin-film heterogeneous mechanical oscillator 2 form an optical interference signal. The corresponding frequency shift information of the thin-film heterogeneous mechanical oscillator can be obtained by detecting the interference signal by a spectrometer.

[0040] The thin-film heterogeneous mechanical oscillator 2 serves as an infrared sensing unit, and the cavity optomechanical system 10 serves as an infrared detection unit. When external infrared radiation 1 irradiates the surface of the thin-film heterogeneous mechanical oscillator 2, the two-dimensional infrared absorbing material layer 7 absorbs it and converts it into heat, thereby causing a temperature change in the thin-film heterogeneous mechanical oscillator 2 and generating mechanical vibration. Different wavelengths and intensities of external infrared radiation 1 cause different temperature changes in the thin-film heterogeneous mechanical oscillator 2, resulting in different degrees of shift in the resonant frequency of the thin-film heterogeneous mechanical oscillator 2. This invention converts external infrared radiation 1 into a shift in the resonant frequency of the thin-film heterogeneous mechanical oscillator 2 itself, and detects external infrared radiation 1 by detecting the frequency shift of the thin-film heterogeneous mechanical oscillator 2.

[0041] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An infrared detection device based on a cavity photodynamic system, characterized in that, include: Thin film heterogeneous mechanical oscillator (2), optical fiber (3) below thin film heterogeneous mechanical oscillator (2), a suspension structure is provided at the center of thin film heterogeneous mechanical oscillator (2), external infrared radiation (1) is above the suspension structure, and optical fiber (3) is directly opposite the center of the suspension structure of thin film heterogeneous mechanical oscillator (2); the end of optical fiber (3) close to thin film heterogeneous mechanical oscillator (2) forms a cavity optical system (10) with thin film heterogeneous mechanical oscillator (2). The suspension structure undergoes up-and-down mechanical vibration after absorbing external infrared radiation (1), and the visible light band detection light (4) is transmitted through the optical fiber (3) as a transmission carrier to the area below the center of the suspension structure of the thin film heterogeneous mechanical oscillator (2). The thin-film heterogeneous mechanical oscillator (2) serves as the infrared sensing unit, and the cavity optical system (10) serves as the infrared detection unit. When the infrared sensing unit is working, external infrared radiation irradiates the thin film heterogeneous mechanical oscillator (2). The two-dimensional infrared absorbing material layer (7) absorbs the incident external infrared radiation (1) and converts the absorbed infrared radiation into heat. This causes the thin film heterogeneous mechanical oscillator (2) to vibrate mechanically under heat, thereby causing a certain degree of shift in the resonant frequency, i.e., frequency shift. By detecting the frequency shift response of the thin film heterogeneous mechanical oscillator (2) under infrared radiation of different wavelengths and intensities in real time, the relationship between infrared radiation and frequency shift can be established, and the detection of infrared radiation can be realized. When the infrared detection unit is working, the visible light detection light (4) is incident vertically below the center of the suspension structure of the thin film heterogeneous mechanical oscillator (2) through the optical fiber (3) as the transmission carrier. At this time, part of the visible light detection light (4) is transmitted at the end of the optical fiber, and the other part is reflected at the end of the optical fiber. The transmitted detection light is reflected back when it encounters the thin film heterogeneous mechanical oscillator (2) and returns along the original path. The detection light reflected at the end of the optical fiber (3) and the detection light reflected back on the thin film heterogeneous mechanical oscillator (2) form an optical interference signal. The corresponding frequency shift information of the thin film heterogeneous mechanical oscillator can be obtained by detecting the interference signal by a spectrometer.

2. The infrared detection device based on a cavity optomechanical system according to claim 1, characterized in that: The thin-film heterogeneous mechanical oscillator (2) is a square frame structure. The frame includes a Si layer (5), a Si3N4 layer (6) above the Si layer (5), and a two-dimensional infrared absorbing material layer (7) above the Si3N4 layer (6) from bottom to top. The square frame structure is hollowed out in the middle. The upper surface of the square frame structure is provided with a suspension structure. The suspension structure includes four tethers (8) and a central platform (9). The four tethers (8) are perpendicular to each other, and the ends of the four tethers (8) near the center are connected together through the central platform (9). The suspension structure undergoes up-and-down mechanical vibration after absorbing external infrared radiation.

3. The infrared detection device based on a cavity optomechanical system according to claim 2, characterized in that: The material of the two-dimensional infrared absorbing material layer (7) is selected from PtSe2 and PdSe2.

4. The infrared detection device based on a cavity optomechanical system according to claim 2, characterized in that: The central platform (9) is a star shape with four circular arc edges, and the intersection of two adjacent circular arc edges is connected to the end of the tether (8) near the central platform.

5. The detection method of the infrared detection device based on a cavity optical system according to any one of claims 1 to 4, characterized in that: The thin-film heterogeneous mechanical oscillator (2) serves as the infrared sensing unit, and the cavity optical system (10) serves as the infrared detection unit. When the infrared sensing unit is working, external infrared radiation irradiates the thin film heterogeneous mechanical oscillator (2). The two-dimensional infrared absorbing material layer (7) absorbs the incident external infrared radiation (1) and converts the absorbed infrared radiation into heat. This causes the thin film heterogeneous mechanical oscillator (2) to vibrate mechanically under heat, thereby causing a certain degree of shift in the resonant frequency, i.e., frequency shift. By detecting the frequency shift response of the thin film heterogeneous mechanical oscillator (2) under infrared radiation of different wavelengths and intensities in real time, the relationship between infrared radiation and frequency shift can be established, and the detection of infrared radiation can be realized. When the infrared detection unit is working, the visible light detection light (4) is incident vertically below the center of the suspension structure of the thin film heterogeneous mechanical oscillator (2) through the optical fiber (3) as the transmission carrier. At this time, part of the visible light detection light (4) is transmitted at the end of the optical fiber, and the other part is reflected at the end of the optical fiber. The transmitted detection light is reflected back when it encounters the thin film heterogeneous mechanical oscillator (2) and returns along the original path. The detection light reflected at the end of the optical fiber (3) and the detection light reflected back on the thin film heterogeneous mechanical oscillator (2) form an optical interference signal. The corresponding frequency shift information of the thin film heterogeneous mechanical oscillator can be obtained by detecting the interference signal by a spectrometer.

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