An acoustic wave detector and system with synergistic enhancement of Fabry-Perot interference and piezoelectric effect

Abstract

The present invention belongs to the field of ultrasensitive acoustic wave detection, and provides an acoustic wave detector and system with synergistic enhancement of Fabry-Perot interference and piezoelectric effect. The resonance sensor includes a piezoelectric thin film with electrodes plated on both sides, a ceramic ferrule, a charge amplifier, a laser light source, a single-mode optical fiber, a circulator, a photodetector, a data acquisition card, and a host computer. By adjusting the size of the piezoelectric thin film, it operates in the first-order resonance mode. The charges generated by the deformation of the piezoelectric thin film are amplified by the charge amplifier and then input to the data acquisition card. In addition, the laser beam is irradiated onto the diaphragm through the circulator, generating reflected light that is coupled to the circulator and transmitted to the photodetector, and then the signal is acquired by the data acquisition card. The two acquired signals are enhanced through calculation on the host computer. The present invention realizes ultrasensitive detection of acoustic waves based on the principles of thin film resonance, piezoelectricity, and Fabry-Perot interference. This sensor can be applied to the detection of weak acoustic wave signals at different frequencies.

Description

Technical Field

[0001] The present invention belongs to the field of ultrasensitive acoustic wave detection, and particularly relates to a piezoelectric thin film resonant acoustic wave sensor and a detection system with synergistic enhancement of Fabry-Perot interference and piezoelectric effect. Background Art

[0002] Disclosing the information of this background art section is only intended to increase the understanding of the overall background of the present invention, and it is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] The demand for ultrasensitive detection technology of acoustic waves is very extensive. For example, it has great application potential in aspects such as sound source localization, ultrasonic imaging, vibration analysis, audio-visual linkage technology, fault-safe voiceprint detection technology, fault real-time detection, and early warning. Among them, the fiber optic Fabry-Perot interferometer is widely used in pressure and acoustic wave sensing due to its characteristics such as anti-electromagnetic interference, long-distance transmission, high resolution, and high sensitivity. The concept of the diaphragm-type fiber optic Fabry-Perot sensor was first proposed in 1987. For the diaphragm-type fiber optic Fabry-Perot sensor, the material properties, effective diameter, and thickness of the diaphragm jointly determine the sensitivity of the sensor. On the other hand, photoacoustic spectroscopy technology, which has been a popular research topic in recent years, performs very prominently in measuring trace gases. However, it has very high requirements for the minimum detectable value of the sensor. The trace gas detection technology has important application value in fields such as atmospheric environment monitoring, medical clinical diagnosis, coal mine safety monitoring, and on-line monitoring of power facilities. Among many gas detection technologies, laser photoacoustic spectroscopy technology has advantages such as high sensitivity and small cross-interference, and thus has received extensive attention.

[0004] Since the detection sensitivity of photoacoustic spectroscopy is proportional to the sensitivity and signal-to-noise ratio of the acoustic wave sensor, various high-performance optical acoustic wave sensors such as optical cantilever acoustic wave sensors and fiber optic sensors have gradually replaced traditional electret microphones. In 2004, Kauppinen et al. designed a silicon microcantilever optical microphone based on a Michelson interferometer and proposed a cantilever-enhanced photoacoustic spectroscopy detection scheme. Compared with diaphragm microphones, optical cantilever microphones have advantages such as good low-frequency response, high sensitivity, and large dynamic response range. However, traditional optical cantilever microphones use a Michelson interferometer structure, which has disadvantages such as large volume, complex system, and inconvenience in matching with the photoacoustic cell. The fiber optic Fabry-Perot microphone can effectively solve the above deficiencies. This sensor uses the fiber end face and the diaphragm to form a Fabry-Perot interferometer. When the acoustic wave acts on the diaphragm, it generates vibration, causing a change in the optical path difference of the interferometer. Its advantage is that the acoustic resistance of the diaphragm is low, so higher sensitivity can be obtained, and the microphone probe based on the Fabry-Perot interferometer structure has a small volume, is suitable for matching with the photoacoustic cell, can effectively improve the overall detection performance and distributable characteristics of the photoacoustic spectroscopy detection system, and has a broader application prospect. However, the detection sensitivity of existing devices still needs to be improved to meet the requirements of ultrasensitive acoustic wave detection. Summary of the Invention

[0005] To solve the above problems, the present invention provides a piezoelectric thin film resonant acoustic wave sensor and detection system with synergistic enhancement of Fabry-Perot interference and piezoelectric effect to achieve the detection of ultrasensitive acoustic waves.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect of the present invention, an acoustic wave detector with synergistic enhancement of Fabry-Perot interference and piezoelectric effect is provided, including: a piezoelectric thin film 1 with electrodes plated on both sides, a charge amplifier 4, a data acquisition card 9, a circulator 7, a laser light source 5, a photodetector 8, and a host computer 10;

[0008] The piezoelectric thin film 1 with electrodes plated on both sides is connected to the charge amplifier 4 by an anti-interference wire, and the charge amplifier 4 is connected to the data acquisition card 9 and the host computer 10 in sequence;

[0009] The piezoelectric thin film 1 with electrodes plated on both sides also forms a Fabry-Perot resonant cavity with a single-mode optical fiber 6. The single-mode optical fiber 6 is connected to the circulator 7, and the circulator 7 is connected to the photodetector 8 and the laser light source 5 respectively.

[0010] In the second aspect of the present invention, an acoustic wave detection system with synergistic enhancement of Fabry-Perot interference and piezoelectric effect is provided, including: the above-mentioned acoustic wave detector with synergistic enhancement of Fabry-Perot interference and piezoelectric effect.

[0011] In a third aspect of the present invention, there is provided an acoustic wave detection method synergistically enhanced by Fabry-Perot interference and piezoelectric effect, including:

[0012] Performing detection using the above-mentioned acoustic wave detector synergistically enhanced by Fabry-Perot interference and piezoelectric effect;

[0013] Using the piezoelectric thin film 1 with double-sided electrodes to detect the piezoelectric effect of the thin film caused by acoustic waves, and then transmitting the signal to the charge amplifier 4, and then sequentially transmitting it to the data acquisition card 9 and the upper computer 10;

[0014] Detecting acoustic waves, causing a beam of incident light generated by the laser light source 5 to enter the single-mode optical fiber 6 through the circulator 7, and the emitted light irradiates the center of the piezoelectric thin film 1 with double-sided electrodes. The end face of the single-mode optical fiber 6 and the piezoelectric thin film 1 with double-sided electrodes form a Fabry-Perot resonant cavity. As the piezoelectric thin film 1 with double-sided electrodes vibrates, the light intensity of the light reflected back to the circulator 7 obtained by the photodetector 8 synchronously changes, and is sequentially transmitted to the data acquisition card 9 and the upper computer 10;

[0015] The upper computer performs a convolution operation on the two signals collected by the signal acquisition card to obtain the phase, frequency, and amplitude information of the acoustic wave signal, that's it.

[0016] Advantages of the present invention

[0017] (1) Based on the Fabry-Perot interference, thin film piezoelectric effect, and thin film resonance principle, the present invention realizes the detection of acoustic waves with specific frequencies. Compared with the previous simple capacitive acoustic sensors and sensors with Fabry-Perot cavity structures, through the convolution operation of the resonance of the thin film, piezoelectric signals, and optical signals of the Fabry-Perot cavity, the minimum detectable sound pressure level can be increased several times. Therefore, the present invention can achieve ultra-high sensitivity, has broad application prospects, and has high practical value in the application of combining fiber optic sensing and piezoelectric effect, especially in the application of trace gas detection in photoacoustic spectroscopy.

[0018] (2) The present invention has a simple structure, is easy to operate, has strong practicability, and is easy to promote. Description of the drawings

[0019] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0020] Figure 1 It is a schematic diagram of the overall structure of the piezoelectric thin film resonance acoustic wave sensor with enhanced Fabry interference of the present invention;

[0021] Figure 2Schematic 3 / 4 cross-section view of the film clamping device of the Fabry interference enhanced piezoelectric thin film resonant acoustic wave sensor of the present invention;

[0022] Wherein, 1 - piezoelectric thin film with double-sided electrodes, 2 - film clamping device, 3 - ceramic ferrule, 4 - charge amplifier, 5 - laser light source, 6 - single-mode optical fiber, 7 - circulator, 8 - photodetector, 9 - data acquisition card, 10 - host computer. Specific embodiments

[0023] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0024] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are explanations rather than limitations of the present invention.

[0025] Embodiment 1

[0026] As Figure 1 shown, the present invention provides a piezoelectric thin film resonant acoustic wave sensor and detection system with synergistic enhancement of Fabry-Perot interference and piezoelectric effect. The acoustic wave sensor and system include: 1 - double-sided silver-plated PVDF piezoelectric thin film, 2 - film clamping device, 3 - ceramic ferrule, 4 - charge amplifier, 5 - laser light source, 6 - single-mode optical fiber, 7 - circulator, 8 - photodetector, 9 - data acquisition card, and 10 - host computer;

[0027] The double-sided silver-plated PVDF piezoelectric thin film 1 is connected to the charge amplifier 2 through anti-interference wires to detect the piezoelectric effect of the thin film caused by acoustic waves; the single-mode optical fiber 6 and the PVDF piezoelectric thin film 1 form a Fabry-Perot resonant cavity, and the generated change in light intensity is measured by the photodetector 8. The two signals are transmitted by the data acquisition card 9 to the host computer 10, and the output response of the sensor to acoustic waves is enhanced through calculations such as real-time convolution.

[0028] The size of the double-sided silver-plated PVDF piezoelectric thin film 1 is related to the frequency of the measured acoustic wave and operates in the first-order resonance mode. The positive and negative electrodes of the piezoelectric thin film are both connected by anti-interference wires and input to the charge amplifier 4 to measure the electric charge generated by the piezoelectric effect.

[0029] A beam of incident light generated by the laser light source 5 enters the single-mode optical fiber 6 through the circulator, and the outgoing light irradiates the center of the silver-plated PVDF piezoelectric film 1. The end face of the single-mode optical fiber 6 and the silver-plated PVDF piezoelectric film 1 form a Fabry-Perot resonator. As the silver-plated PVDF piezoelectric film 1 vibrates, the intensity of the reflected light coupled to the circulator 7 obtained by the photodetector 8 changes synchronously.

[0030] Optionally, the sensor and system unit includes:

[0031] Optionally, the size of the double-sided silver-plated PVDF piezoelectric film 1 is adjusted according to the required operating frequency, including the thickness of the silver-plated film, the thickness and diameter of the PVDF film, so that it operates in the first-order resonance mode.

[0032] Optionally, the thickness of the silver-plated PVDF piezoelectric film is 25 μm - 45 μm, and the diameter is 9 mm - 20 mm.

[0033] Optionally, the film clamping device 2 has insulating properties and clamps and fixes the PVDF film 1 well.

[0034] Optionally, the ceramic ferrule 3 fixes the single-mode optical fiber 6 and inserts it into the film clamping device 2 to form a Fabry-Perot resonator with the double-sided silver-plated PVDF piezoelectric film 1.

[0035] Optionally, the laser light source 5 is selected with a wavelength range of 1 μm - 2 μm.

[0036] Optionally, the length of the Fabry-Perot cavity is adjusted to 10 μm - 200 μm.

[0037] Optionally, the core diameter of the single-mode optical fiber 6 is 9 μm, the outer diameter of the cladding is 125 μm, and the end is cut into a plane by an optical fiber cutter.

[0038] Optionally, the wavelength range detected by the photodetector 8 needs to cover the output wavelength range of the broadband light source.

[0039] Optionally, the data acquisition card 9 collects and transmits the signals of the charge amplifier 4 and the photodetector 8 to the host computer 10.

[0040] Optionally, the host computer 10 performs a convolution operation on the two signals collected by the signal acquisition card 9 to obtain information such as the phase, frequency, and amplitude of the acoustic wave signal.

[0041] Embodiment 2

[0042] As Figure 1As shown in the figure, the present invention provides a piezoelectric thin-film resonant acoustic wave sensor and detection system that synergistically enhances the Fabry-Perot interference and piezoelectric effect. The acoustic wave sensor and system include: 1 - double-sided silver-plated PVDF piezoelectric thin film, 2 - thin-film clamping device, 3 - ceramic ferrule, 4 - charge amplifier, 5 - laser light source, 6 - single-mode optical fiber, 7 - circulator, 8 - photodetector, 9 - data acquisition card, and 10 - host computer;

[0043] The double-sided silver-plated PVDF piezoelectric thin film 1 is connected to the charge amplifier 2 through anti-interference wires to detect the piezoelectric effect of the thin film caused by acoustic waves; the single-mode optical fiber 6 and the PVDF piezoelectric thin film 1 form a Fabry-Perot resonant cavity, and the generated change in light intensity is measured by the photodetector 8. The two signals are transmitted by the data acquisition card 9 to the host computer 10, and the output response of the sensor to acoustic waves is enhanced through calculations such as real-time convolution.

[0044] The size of the double-sided silver-plated PVDF piezoelectric thin film 1 is related to the measured acoustic wave frequency and operates in the first-order resonance mode. The positive and negative electrodes of the piezoelectric thin film are both connected by anti-interference wires and input to the charge amplifier 4 to measure the electric charge generated by the piezoelectric effect.

[0045] A beam of incident light generated by the laser light source 5 enters the single-mode optical fiber 6 through the circulator, and the emitted light irradiates the center of the silver-plated PVDF piezoelectric thin film 1. The end face of the single-mode optical fiber 6 and the silver-plated PVDF piezoelectric thin film 1 form a Fabry-Perot resonant cavity. As the silver-plated PVDF piezoelectric thin film 1 vibrates, the light intensity of the reflected light coupled to the circulator 7 obtained by the photodetector 8 changes synchronously.

[0046] Optionally, the sensor and system unit includes:

[0047] Optionally, the size of the double-sided silver-plated PVDF piezoelectric thin film 1 is adjusted according to the required operating frequency, including the thickness of the silver-plated film, the thickness and diameter of the PVDF film, so that it operates in the first-order resonance mode.

[0048] Optionally, the thickness of the silver-plated PVDF piezoelectric thin film is 10 μm - 35 μm, and the diameter is 5 mm - 20 mm.

[0049] Optionally, the thin-film clamping device 2 has insulating properties and firmly clamps and fixes the PVDF thin film 1.

[0050] Optionally, the ceramic ferrule 3 fixes the single-mode optical fiber 6 and inserts it into the thin-film clamping device 2 to form a Fabry-Perot resonant cavity with the double-sided silver-plated PVDF piezoelectric thin film 1.

[0051] Optionally, the laser light source 5 is selected with a wavelength range of 1 μm - 3 μm.

[0052] Optionally, the length of the Fabry - Perot cavity is adjusted to 20 μm - 200 μm.

[0053] Optionally, the core diameter of the single - mode optical fiber 6 is 9 μm, the outer diameter of the cladding is 125 μm, and the end is cut into a flat surface by an optical fiber cutter.

[0054] Optionally, the wavelength range detected by the photodetector 8 needs to cover the output wavelength range of the broadband light source.

[0055] Optionally, the data acquisition card 9 acquires and transmits the signals of the charge amplifier 4 and the photodetector 8 to the host computer 10.

[0056] Optionally, the host computer 10 performs a convolution operation on the two signals acquired by the signal acquisition card 9 to obtain information such as the phase, frequency, and amplitude of the acoustic wave signal.

[0057] Embodiment 3

[0058] As Figure 1 shown, the present invention provides a piezoelectric thin - film resonant acoustic wave sensor and a detection system with synergistic enhancement of Fabry - Perot interference and piezoelectric effect. The acoustic wave sensor and system include: 1 - double - sided platinum - plated PVDF - TrFE piezoelectric thin film, 2 - thin - film clamping device, 3 - ceramic ferrule, 4 - charge amplifier, 5 - laser light source, 6 - single - mode optical fiber, 7 - circulator, 8 - photodetector, 9 - data acquisition card, and 10 - host computer;

[0059] The double - sided platinum - plated PVDF - TrFE piezoelectric thin film 1 is connected to the charge amplifier 2 through an anti - interference wire to detect the piezoelectric effect of the thin film caused by the acoustic wave; the single - mode optical fiber 6 and the PVDF - TrFE piezoelectric thin film 1 form a Fabry - Perot resonant cavity, and the generated change in light intensity is measured by the photodetector 8. The two signals are transmitted to the host computer 10 by the data acquisition card 9, and the output response of the sensor to the acoustic wave is enhanced through real - time convolution and other calculations.

[0060] The size of the double - sided platinum - plated PVDF - TrFE piezoelectric thin film 1 is related to the measured acoustic wave frequency, and it works in the first - order resonance mode. The positive and negative electrodes of the piezoelectric thin film are both connected by anti - interference wires and input to the charge amplifier 4 to measure the electric charge generated by the piezoelectric effect.

[0061] A beam of incident light generated by the laser light source 5 enters the single-mode optical fiber 6 through the circulator, and the emitted light irradiates the center of the platinum-plated PVDF-TrFE piezoelectric film 1. The end face of the single-mode optical fiber 6 and the platinum-plated PVDF-TrFE piezoelectric film 1 form a Fabry-Perot resonator. As the platinum-plated PVDF-TrFE piezoelectric film 1 vibrates, the light intensity of the reflected light coupled to the circulator 7 obtained by the photodetector 8 changes synchronously.

[0062] Optionally, the sensor and system unit includes:

[0063] Optionally, the size of the double-sided platinum-plated PVDF-TrFE piezoelectric film 1 is adjusted according to the required operating frequency, including the thickness of the platinum-plated film, the thickness of the PVDF-TrFE film, and the diameter, so that it operates in the first resonance mode.

[0064] Optionally, the thickness of the platinum-plated PVDF-TrFE piezoelectric film is 20 μm - 35 μm, and the diameter is 7 mm - 10 mm.

[0065] Optionally, the film clamping device 2 has insulating properties and clamps and fixes the PVDF-TrFE film 1 well.

[0066] Optionally, the ceramic ferrule 3 fixes the single-mode optical fiber 6 and inserts it into the film clamping device 2 to form a Fabry-Perot resonator with the double-sided platinum-plated PVDF-TrFE piezoelectric film 1.

[0067] Optionally, the laser light source 5 is selected with a wavelength range of 0.5 μm - 3 μm.

[0068] Optionally, the length of the Fabry-Perot cavity is adjusted to 40 μm - 300 μm.

[0069] Optionally, the core diameter of the single-mode optical fiber 6 is 9 μm, the outer diameter of the cladding is 125 μm, and the end is cut into a flat surface by an optical fiber cutter.

[0070] Optionally, the wavelength range detected by the photodetector 8 needs to cover the output wavelength range of the laser light source.

[0071] Optionally, the data acquisition card 9 collects and transmits the signals of the charge amplifier 4 and the photodetector 8 to the upper computer 10.

[0072] Optionally, the upper computer 10 performs a convolution operation on the two signals collected by the signal acquisition card 9 to obtain information such as the phase, frequency, and amplitude of the acoustic wave signal.

[0073] Embodiment 4

[0074] As Figure 1As shown in the figure, the present invention provides a piezoelectric thin film resonant acoustic wave sensor and a detection system with synergistic enhancement of Fabry-Perot interference and piezoelectric effect. The acoustic wave sensor and system include: 1 - double-sided platinum-plated PVDF-TrFE piezoelectric thin film, 2 - thin film clamping device, 3 - ceramic ferrule, 4 - charge amplifier, 5 - laser light source, 6 - single-mode optical fiber, 7 - circulator, 8 - photodetector, 9 - data acquisition card, and 10 - upper computer;

[0075] The double-sided platinum-plated PVDF-TrFE piezoelectric thin film 1 is connected to the charge amplifier 2 through anti-interference wires to detect the piezoelectric effect of the thin film caused by acoustic waves; the single-mode optical fiber 6 and the PVDF-TrFE piezoelectric thin film 1 form a Fabry-Perot resonant cavity, and the generated change in light intensity is measured by the photodetector 8. The two signals are transmitted by the data acquisition card 9 to the upper computer 10, and the output response of the sensor to acoustic waves is enhanced through calculations such as real-time convolution.

[0076] The size of the double-sided platinum-plated PVDF-TrFE piezoelectric thin film 1 is related to the measured acoustic wave frequency and operates in the first-order resonance mode. The positive and negative electrodes of the piezoelectric thin film are both connected by anti-interference wires and input to the charge amplifier 4 to measure the electric charge generated by the piezoelectric effect.

[0077] A beam of incident light generated by the laser light source 5 enters the single-mode optical fiber 6 through the circulator, and the outgoing light irradiates the center of the platinum-plated PVDF-TrFE piezoelectric thin film 1. The end face of the single-mode optical fiber 6 and the platinum-plated PVDF-TrFE piezoelectric thin film 1 form a Fabry-Perot resonant cavity. As the platinum-plated PVDF-TrFE piezoelectric thin film 1 vibrates, the light intensity of the reflected light coupled to the circulator 7 obtained by the photodetector 8 changes synchronously.

[0078] Optionally, the sensor and system unit includes:

[0079] Optionally, the size of the double-sided platinum-plated PVDF-TrFE piezoelectric thin film 1 is adjusted according to the required operating frequency, including the thickness of the platinum-plated thin film, the thickness and diameter of the PVDF-TrFE film, so that it operates in the first-order resonance mode.

[0080] Optionally, the thickness of the platinum-plated PVDF-TrFE piezoelectric thin film is 15 μm - 30 μm, and the diameter is 3 mm - 9 mm.

[0081] Optionally, the thin film clamping device 2 has insulating properties and clamps and fixes the PVDF-TrFE thin film 1 well.

[0082] Optionally, the ceramic ferrule 3 fixes the single-mode optical fiber 6 and inserts it into the thin film clamping device 2 to form a Fabry-Perot resonator with the double-sided platinum-plated PVDF-TrFE piezoelectric thin film 1.

[0083] Optionally, the laser light source 5 is selected with a wavelength range of 0.5μm - 4μm.

[0084] Optionally, the length of the Fabry-Perot cavity is adjusted to 50μm - 200μm.

[0085] Optionally, the core diameter of the single-mode optical fiber 6 is 9μm, the cladding outer diameter is 125μm, and the end is cut into a flat surface by an optical fiber cutter.

[0086] Optionally, the wavelength range detected by the photodetector 8 needs to cover the output wavelength range of the laser light source.

[0087] Optionally, the data acquisition card 9 collects and transmits the signals of the charge amplifier 4 and the photodetector 8 to the host computer 10.

[0088] Optionally, the host computer 10 performs convolution operations on the two signals collected by the signal acquisition card 9 to obtain information such as the phase, frequency, and amplitude of the acoustic wave signal.

[0089] According to the specific embodiments provided by the present invention, the test results are as follows:

[0090] Table 1

[0091] Film type Diameter (mm) Thickness (μm) Resonance frequency (Hz) Noise reduction rate <![CDATA[Detection limit (μPa / Hz 1 / 2 )]]> Silver-coated PVDF piezoelectric film on both sides (Example 1) 9-20 20-45 1680 85.23％ 0.78 Silver-coated PVDF piezoelectric film on both sides (Example 2) 5-20 10-35 1560 88.89％ 0.76 Platinum-coated PVDF-TrFE piezoelectric film on both sides (Example 3) 7-10 20-35 2680 93.65％ 0.41 Platinum-coated PVDF-TrFE piezoelectric film on both sides (Example 4) 3-9 15-30 3160 91.01％ 0.71 Calibrated sensor (B&K4189) —— —— —— —— 8

[0092] It can be seen that based on the Fabry-Perot interference, thin film piezoelectric effect, and thin film resonance principle, the present invention realizes the detection of specific frequency acoustic waves. Compared with the previous simple capacitive acoustic sensors and sensors with Fabry-Perot cavity structures, through the convolution operations of the resonance of the thin film, piezoelectric signals, and optical signals of the Fabry-Perot cavity, the lowest detectable sound pressure level can be increased several times. Therefore, the present invention can achieve ultra-high sensitivity, has broad application prospects, and has high practical value in the application of combining fiber optic sensing and piezoelectric effect, especially in the application of trace gas detection in photoacoustic spectroscopy.

[0093] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An acoustic wave detector with synergistic enhancement of Fabry - Perot interference and piezoelectric effect, characterized in that, Comprising: A piezoelectric thin film (1) with double-sided plated electrodes, a charge amplifier (4), a data acquisition card (9), a circulator (7), a laser light source (5), a photodetector (8), and a host computer (10); The piezoelectric thin film (1) with double-sided plated electrodes is connected to the charge amplifier (4) by an anti-interference wire, and the charge amplifier (4) is sequentially connected to the data acquisition card (9) and the host computer (10); The piezoelectric thin film (1) with double-sided plated electrodes also forms a Fabry-Perot resonator with a single-mode optical fiber (6), the single-mode optical fiber (6) is connected to the circulator (7), and the circulator (7) is respectively connected to the photodetector (8) and the laser light source (5); The piezoelectric thin film (1) with double-sided plated electrodes operates in the first-order resonance mode; A beam of incident light generated by the laser light source (5) enters the single-mode optical fiber (6) through the circulator (7), and the outgoing light irradiates the center of the piezoelectric thin film (1) with double-sided plated electrodes. The end face of the single-mode optical fiber (6) and the piezoelectric thin film (1) with double-sided plated electrodes form a Fabry-Perot resonator. As the piezoelectric thin film (1) with double-sided plated electrodes vibrates, the light intensity reflected back to the circulator (7) obtained by the photodetector (8) changes synchronously; The wavelength range detected by the acoustic wave detector covers the output wavelength range of the broadband light source; The data acquisition card collects and transmits the signals of the charge amplifier and the photodetector to the host computer; The host computer performs a convolution operation on the two signals collected by the data acquisition card to obtain the phase, frequency, and amplitude information of the acoustic wave signal.

2. The Fabry-Perot interference and piezoelectric effect synergistically enhanced acoustic wave detector according to claim 1, characterized in that A ceramic ferrule (3) is arranged at the center position of the piezoelectric thin film (1) with double-sided plated electrodes. A single-mode optical fiber (6) is fixed inside the ceramic ferrule (3) and makes the single-mode optical fiber (6) contact with the piezoelectric thin film (1) with double-sided plated electrodes.

3. The Fabry-Perot interference and piezoelectric effect synergistically enhanced acoustic wave detector according to claim 1, characterized in that A film clamping device (2) is arranged outside the piezoelectric thin film (1) with double-sided plated electrodes; The piezoelectric thin film (1) with double-sided plated electrodes is a double-sided silver-plated PVDF piezoelectric thin film or a double-sided platinum-plated PVDF-TrFE piezoelectric thin film.

4. The Fabry-Perot interference and piezoelectric effect synergistically enhanced acoustic wave detector according to claim 3, wherein The thickness of the silver-plated PVDF piezoelectric thin film is 25μm - 45μm, and the diameter is 9mm - 20mm; Or, the thickness of the silver-plated PVDF piezoelectric thin film is 10μm - 35μm, and the diameter is 5mm - 20mm; Or, the thickness of the platinum-plated PVDF-TrFE piezoelectric thin film is 20μm - 35μm, and the diameter is 7mm - 10mm; Or, the thickness of the platinum-plated PVDF-TrFE piezoelectric thin film is 15μm - 30μm, and the diameter is 3mm - 9mm.

5. The Fabry-Perot interference and piezoelectric effect synergistically enhanced acoustic wave detector according to claim 1, characterized in that The laser light source is selected with a wavelength range of 1μm - 2μm.

6. The Fabry-Perot interference and piezoelectric effect synergistically enhanced acoustic wave detector according to claim 1, characterized in that, The length of the Fabry-Perot cavity is 10μm - 200μm; Or, the core diameter of the single-mode optical fiber 6 is 9μm, the outer diameter of the cladding is 125μm, and the end of the single-mode optical fiber 6 is flat.

7. An acoustic wave detection system with synergistic enhancement of Fabry - Perot interference and piezoelectric effect, characterized in that, Comprising: An acoustic wave detector with synergistic enhancement of Fabry-Perot interference and piezoelectric effect according to any one of claims 1-6.

8. An acoustic wave detection method with synergistic enhancement of Fabry - Perot interference and piezoelectric effect, characterized in that, Comprising: Detecting by using the acoustic wave detector with synergistic enhancement of Fabry-Perot interference and piezoelectric effect according to any one of claims 1-6; The piezoelectric thin film (1) with double-sided plated electrodes is used to detect the piezoelectric effect of the thin film caused by sound waves. Then, the signal is transmitted to the charge amplifier (4), and then sequentially transmitted to the data acquisition card (9) and the host computer (10). Sound waves are detected, and a beam of incident light generated by the laser light source (5) enters the single-mode optical fiber (6) through the circulator (7). The outgoing light irradiates the center of the piezoelectric thin film (1) with double-sided plated electrodes. The end face of the single-mode optical fiber (6) and the piezoelectric thin film (1) with double-sided plated electrodes form a Fabry-Perot resonator. As the piezoelectric thin film (1) with double-sided plated electrodes vibrates, the light intensity of the light reflected back to the circulator (7) obtained by the photodetector (8) changes synchronously, and is sequentially transmitted to the data acquisition card (9) and the host computer (10). The host computer performs a convolution operation on the two signals collected by the data acquisition card to obtain the phase, frequency, and amplitude information of the sound wave signal, and that's it.

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