Accurate testing system and method for high-frequency acoustic attenuation coefficient of acousto-optic material

Abstract

The application discloses a kind of accurate test system and method of high-frequency acoustic attenuation coefficient of acousto-optic material, by setting pulse signal emission receiving module, signal processing and data display module, ultrasonic transducer, coupling agent and the precision coupling device including spiral side swing type pressure control machine platform and object table, a complete high-frequency acoustic attenuation coefficient test system is constructed.The system can improve the consistency of coupling interface in the process of high-frequency acoustic attenuation coefficient test of acousto-optic material, reduce the signal fluctuation introduced by coupling state fluctuation, realize accurate measurement, while reducing the dependence on complex equipment and high-precision assembly process, with good engineering practicability and generalizability.The method is corrected by reflection loss and diffraction loss, solves the problem of unstable coupling and large system error in the prior art, significantly improves the measurement accuracy, and has good repeatability and consistency under different test conditions, so as to obtain accurate intrinsic acoustic attenuation coefficient.

Description

Technical Field

[0001] This invention belongs to the field of non-destructive testing technology, specifically relating to a precise testing system and method for the high-frequency acoustic attenuation coefficient of acousto-optic materials. Background Technology

[0002] Acousto-optic materials are the core functional components of acousto-optic devices, widely used in laser modulation, optical communication, and optical information processing. With the continuous development of high-frequency modulation technology, the operating frequency of ultrasound in acousto-optic devices has been continuously increasing (reaching 20-200 MHz). The energy loss and thermal effects of ultrasound propagation within the material are becoming increasingly significant, severely limiting the operating efficiency and long-term stability of acousto-optic devices. Therefore, accurately characterizing the energy loss characteristics of ultrasound in acousto-optic materials is of great importance for evaluating device performance boundaries and optimizing the stable operating range.

[0003] The acoustic attenuation coefficient refers to the rate of sound energy attenuation caused by the absorption and scattering of sound waves within a material. Currently, transmission and pulse-echo methods are the primary methods used in engineering practice for measurement.

[0004] The transmission method is suitable for measuring materials with high acoustic attenuation coefficients, but it requires that the transmitter and receiver be in the same straight line position, which makes the system difficult to assemble and adjust, and requires extremely high equipment accuracy, thus limiting its practical application.

[0005] While the pulse-echo method is relatively simple to operate, it has significant technical limitations. For example, Treiber et al., in their 2009 article "Correction for partial reflection in ultrasonic attenuation measurements using contact transducers," pointed out that: firstly, the coupling state between the ultrasonic transducer and the sample under test is unstable, leading to fluctuations in the echo signal; secondly, under high-frequency conditions, the acoustic impedance mismatch between the sample under test and the coupling agent introduces interface reflection loss; and thirdly, the acoustic wave divergence characteristics of the ultrasonic transducer cause beam diffusion loss. These factors result in insufficient accuracy of the pulse-echo method in measuring acoustic attenuation coefficients, and existing techniques mostly use it for sound velocity measurement rather than the precise determination of acoustic attenuation coefficients. Especially when the operating frequency increases to the hundreds of MHz level, the sensitivity of coupling layer thickness and acoustic impedance matching further increases, and existing methods have significant shortcomings in characterizing the high-frequency acoustic attenuation characteristics of acousto-optic materials. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a precise testing system and method for the high-frequency acoustic attenuation coefficient of acousto-optic materials, addressing the shortcomings of existing technologies. This system improves the consistency of the coupling interface during the testing of the high-frequency acoustic attenuation coefficient of acousto-optic materials, reduces signal fluctuations caused by coupling state fluctuations, and achieves accurate measurement. Simultaneously, this system reduces reliance on complex equipment and high-precision assembly processes, exhibiting good engineering practicality and scalability. This method solves the problems of unstable coupling and large system errors in existing technologies, significantly improving measurement accuracy and demonstrating good repeatability and consistency under different testing conditions, thereby obtaining an accurate intrinsic acoustic attenuation coefficient.

[0007] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a precise testing system for the high-frequency acoustic attenuation coefficient of acousto-optic materials, the system comprising: The pulse signal transmitting and receiving module is configured to generate and process high-frequency electrical signals, output tunable electrical pulse excitation signals, and simultaneously receive and process ultrasonic echo electrical signals of the same frequency band and transmit them to the signal processing and data display module. The signal processing and data display module is configured to analyze and process the received ultrasonic echo signals, display the echo propagation time and voltage amplitude in real time, and support data recording and calculation result output. An ultrasonic transducer is configured to convert an electrical pulse signal into an ultrasonic signal and transmit it to the sample under test, while simultaneously converting the ultrasonic echo signal reflected by the sample under test into an ultrasonic echo electrical signal and feeding it back to the pulse signal transmitting and receiving module. A coupling agent, coated between the ultrasonic transducer and the sample under test, is configured to reduce interfacial acoustic energy loss. The precision coupling device includes a helical side-rocking pressure control platform and a stage. The helical side-rocking pressure control platform can apply quantifiable axial pressure to the ultrasonic transducer and the sample under test while driving the stage to perform three-dimensional spatial pose adjustment, so that a stable thin-layer liquid coupling interface is formed between the ultrasonic transducer and the sample under test.

[0008] This invention constructs a complete high-frequency acoustic attenuation coefficient testing system by incorporating a pulse signal transmission and reception module, a signal processing and data display module, an ultrasonic transducer, a coupling agent, and a precision coupling device including a helical rocking pressure control stage and a sample stage. The helical rocking pressure control stage can apply quantifiable axial pressure while adjusting the three-dimensional orientation of the sample stage, forming a stable thin-layer liquid coupling interface between the ultrasonic transducer and the sample under test. This transforms the coupling state from an unstable contact dependent on operational experience to a stable contact with controllable mechanical parameters. This invention's testing system improves the consistency of the coupling interface during high-frequency acoustic attenuation coefficient testing of acousto-optic materials, reduces signal fluctuations caused by coupling state fluctuations, and achieves accurate measurement.

[0009] Preferably, the tunable electrical pulse excitation signal is a tunable electrical pulse excitation signal with a center frequency of 20-200 MHz. By limiting the center frequency range of the tunable electrical pulse excitation signal output by the pulse signal transmitting and receiving module, the test system can cover the frequency range required by the development of high-frequency modulation technology and meet the test requirements of the acoustic attenuation coefficient in the 20-200 MHz operating frequency band.

[0010] Preferably, the center operating frequency of the ultrasonic transducer covers 20-200 MHz, and the -6 dB relative bandwidth is not less than 60%. By limiting the center operating frequency range and bandwidth of the ultrasonic transducer, sufficient bandwidth in the high-frequency band is ensured to effectively excite and receive broadband ultrasonic signals, improve the time domain resolution of high-frequency ultrasonic signals, make the bottom echo signal clearly distinguishable, and facilitate the accurate extraction of echo amplitude and propagation time.

[0011] Preferably, the coupling agent is a low-volatility liquid coupling medium. Selecting a low-volatility liquid coupling medium with stable performance under high-frequency testing conditions can reduce the impact of the coupling agent's own volatilization or denaturation on the acoustic coupling effect, thus maintaining the consistency of acoustic transmission conditions during testing. Olympus SWC-2 type coupling agent is preferred as the liquid coupling medium.

[0012] A precise testing method for the high-frequency acoustic attenuation coefficient of acousto-optic materials using the above system, the testing method comprising the following steps: S1. Construct a precision coupling device and connect it to the pulse signal transmitting and receiving module, signal processing and data display module respectively. Power on, debug and initialize each module. S2. Select a thickness of d The sample to be tested is coated with a layer of coupling agent evenly on its surface and then placed on the stage. S3. Align and bond the ultrasonic transducer with the surface of the sample to be tested, which has been coated with coupling agent, and adjust the spiral side-rocking pressure control machine to apply coupling pressure to form a stable acoustic coupling interface; S4. Record the propagation time of the first bottom echo. t 1. Second bottom surface echo time t 2. First bottom surface echo voltage amplitude P 1 and the amplitude of the second bottom surface echo voltage P 2. And calculate the sound velocity of the sample under test based on the recorded data. c 1 and characterizing the sound attenuation coefficient α 1; S5. Based on Bessel function and normalized distance s iThe diffraction loss coefficient was calculated. D ( s i ), and combined with the reflection coefficient R， Characterizing the sound attenuation coefficient α 1. Perform diffraction loss and reflection loss correction to obtain the intrinsic acoustic attenuation coefficient. α 0.

[0013] The test method of this invention eliminates the influence of ultrasonic beam diffusion and interface impedance mismatch on the measurement results by jointly correcting the two main sources of systematic error: diffraction loss and reflection loss. This makes the final intrinsic acoustic attenuation coefficient more accurate and can truly reflect the absorption and scattering characteristics of the material itself. It solves the problems of unstable coupling and large systematic errors in the prior art, significantly improves the measurement accuracy, and has good repeatability and consistency under different test conditions.

[0014] Preferably, in step S4, the sound velocity of the sample to be tested... c The formula for calculating 1 is: .

[0015] Preferably, in step S4, the sample to be tested characterizes the acoustic attenuation coefficient. α The formula for calculating 1 is: .

[0016] Preferably, in step S5, the distance is normalized based on the Bessel function. s i The diffraction loss coefficient was calculated. D ( s i The formula for calculating ) is: , In the formula, i Choose 1 or 2, which correspond to the first bottom surface echo and the second bottom surface echo, respectively; s 1 represents the normalized distance corresponding to the first bottom surface echo. s 2 represents the normalized distance corresponding to the second bottom surface echo; m The index variable for summing a series.

[0017] The method described above for calculating the diffraction loss coefficient based on the Bessel function and normalized distance has the advantage of quantitatively describing the energy loss caused by the diffusion of the ultrasonic beam through a theoretical model, avoiding reliance on empirical correction or complex calibration, so as to accurately deduct the diffraction loss under different propagation distances and improve the accuracy of the sound attenuation coefficient measurement.

[0018] Preferably, in step S5, the reflection coefficient R The calculation formula is: , In the formula, The acoustic impedance of the sample under test. The acoustic impedance of the coupling agent. ρ 1 and ρ 2 represents the density of the sample to be tested and the coupling agent, respectively. c 1 and c 2 represents the sound velocity of the sample under test and the coupling agent, respectively.

[0019] The above calculation formula uses the density of the sample under test and the coupling agent, as well as the sound velocity, to calculate the acoustic characteristic impedance and then obtain the reflection coefficient. R Its advantage lies in the fact that it quantitatively calculates reflection loss based on the material's inherent properties, eliminating the need for additional experimental measurements. This calculation formula can accurately deduct energy reflection caused by acoustic impedance mismatch at the coupling interface, further improving the accuracy of acoustic attenuation coefficient measurement.

[0020] Preferably, in step S5, the intrinsic sound attenuation coefficient α The formula for calculating 0 is: .

[0021] Compared with the prior art, the present invention has the following advantages: (1) The testing system proposed in this invention constructs a complete high-frequency acoustic attenuation coefficient testing system by setting up a pulse signal transmission and reception module, a signal processing and data display module, an ultrasonic transducer, a coupling agent, and a precision coupling device including a helical side-rolling pressure control platform and a stage. The helical side-rolling pressure control platform can apply quantifiable axial pressure while adjusting the three-dimensional pose of the stage, so that a stable thin-layer liquid coupling interface is formed between the ultrasonic transducer and the sample under test, thereby changing the coupling state from an unstable contact dependent on operational experience to a stable contact with controllable mechanical parameters. As a result, this testing system can improve the consistency of the coupling interface during the high-frequency acoustic attenuation coefficient testing of acousto-optic materials, reduce signal fluctuations caused by coupling state fluctuations, and achieve accurate measurement. At the same time, the system is based on the reliable connection between the precision coupling device and the pulse signal transmission and reception module, the signal processing module, and the data display module, which reduces the dependence on complex equipment and high-precision assembly and adjustment processes, and has good engineering practicality and scalability.

[0022] (2) The test method proposed in this invention analyzes the sources of error in the acoustic attenuation coefficient test, and performs joint correction of reflection loss and diffraction loss, eliminating the influence of ultrasonic beam diffusion and interface impedance mismatch on the measurement results, effectively eliminating systematic errors, and making the final intrinsic acoustic attenuation coefficient more accurate, which can truly reflect the absorption and scattering characteristics of the material itself. This method solves the problems of unstable coupling and large systematic errors in the prior art, significantly improves the measurement accuracy, and has good repeatability and consistency under different test conditions, thereby obtaining an accurate intrinsic acoustic attenuation coefficient. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the test system in Example 1; Figure 2 This is a schematic diagram of the test interface of the signal processing and data display module in Example 2. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Components not limited in the present invention are all constructed using conventional techniques in the art.

[0025] Example 1: A precise testing system for the high-frequency acoustic attenuation coefficient of acousto-optic materials, such as... Figure 1 As shown, the system includes a pulse signal transmitting and receiving module 1, a signal processing and data display module 2, an ultrasonic transducer 4, a coupling agent 5, and a precision coupling device 3. The pulse signal transmitting and receiving module 1 is communicatively connected to the signal processing and data display module 2 and the ultrasonic transducer 4. Specifically, the core of the pulse signal transmitting and receiving module 1 is a commercially available JSR DPR500 pulse transmitter and receiver; the core of the signal processing and data display module 2 is a commercially available OKOS AL8×GTE-1 high-precision data acquisition card; the ultrasonic transducer 4 is a commercially available Olympus V100 ultrasonic transducer; and the core of the precision coupling device 3 is a commercially available Shanghai Siwei Instrument Manufacturing Co., Ltd. SLR-500-500 spiral side-rocking pressure control machine.

[0026] The pulse signal transmitting and receiving module 1 is configured to generate and process high-frequency electrical signals, outputting tunable electrical pulse excitation signals with a center frequency of 20-200 MHz, and simultaneously receiving and processing ultrasonic echo electrical signals of the same frequency band to transmit to the signal processing and data display module 2. The signal processing and data display module 2 is configured to analyze and process the received ultrasonic echo signals, display the echo propagation time and voltage amplitude in real time, and support data recording and calculation result output. The ultrasonic transducer 4 is configured to convert the electrical pulse signal into an ultrasonic signal and transmit it to the sample under test 6, while converting the ultrasonic echo signal reflected by the sample under test 6 into an ultrasonic echo electrical signal and feeding it back to the pulse signal transmitting and receiving module 1. The center operating frequency of the ultrasonic transducer 4 covers 20-200 MHz, and the -6 dB relative bandwidth is not less than 60%. The coupling agent 5 is coated between the ultrasonic transducer 4 and the sample under test 6 and is configured to reduce interface acoustic energy loss. The coupling agent 5 is a low-volatility liquid coupling medium. In this embodiment, commercially available Olympus SWC-2 type coupling agent 5 is specifically used. The precision coupling device 3 includes a spiral side-rocking pressure control platform 31 and a stage 32. The spiral side-rocking pressure control platform 31 can apply quantifiable axial pressure to the ultrasonic transducer 4 and the sample 6 under test while driving the stage 32 to perform three-dimensional spatial pose adjustment, so that a stable thin-layer liquid coupling interface is formed between the ultrasonic transducer 4 and the sample 6 under test.

[0027] Example 2: A precise testing method for the high-frequency acoustic attenuation coefficient of acousto-optic materials implemented using the system of Example 1, the steps of which include: S1. Construct a precision coupling device 3 and connect it to the pulse signal transmitting and receiving module 1 and the signal processing and data display module 2 respectively. Power on, debug and initialize each module.

[0028] S2. Select a thickness of d The test sample 6 should have a lateral dimension greater than twice the effective diameter of the ultrasonic transducer 4, and its two main test surfaces should have good parallelism and surface accuracy to ensure that the ultrasonic echo signal is clearly distinguishable. Then, after uniformly coating a layer of coupling agent 5 on the surface of the test sample 6, it is placed on the stage 32.

[0029] S3. Align and bond the ultrasonic transducer 4 with the surface of the sample 6 to be tested, which has been coated with coupling agent 5. Adjust the spiral side-rocking pressure control platform 31 to slowly apply the continuously increasing axial coupling pressure and simultaneously observe the bottom echo peak in the signal processing and data display module 2. When the fluctuation value of the amplitude of the adjacent bottom echo peak does not exceed 5% within 30 seconds, maintain the pressure for at least 1 minute to ensure the formation of a stable acoustic coupling interface.

[0030] S4. In the operation interface of signal processing and data display module 2, such as Figure 2 As shown, the first and second clearly distinguishable bottom echo peaks received after the system stabilized were selected as the signal processing objects; the propagation time of the first bottom echo was recorded. t 1. Second bottom surface echo time t 2. First bottom surface echo voltage amplitude P 1 and the amplitude of the second bottom surface echo voltage P 2. Based on the recorded data, the sound velocity of the test sample 6 was calculated. c 1 and characterizing the sound attenuation coefficient α 1, of which: The speed of sound of the sample under test c The formula for calculating 1 is: (1) Sample 6 is used to characterize the sound attenuation coefficient. α The formula for calculating 1 is: (2) To improve the reliability of the measurement results, the above process needs to be repeated multiple times, and the final sound velocity is obtained. c 1 and characterizing the sound attenuation coefficient α The arithmetic mean of 1 is used as the measurement result.

[0031] S5. Due to the sound attenuation coefficient measured in step S4 α The error of 1 mainly originates from diffraction loss caused by ultrasonic beam diffusion and reflection loss caused by the acoustic impedance mismatch between the coupler and the test sample. Therefore, to eliminate systematic errors, the distance is normalized based on the Bessel function. s i The diffraction loss coefficient was calculated. D ( s i ), and combined with the reflection coefficient R， Characterizing the sound attenuation coefficient α 1. Perform diffraction loss and reflection loss correction to obtain the intrinsic acoustic attenuation coefficient. α 0, where: Normalized distance s i Calculate according to formula (3): (3) In the formula, i Choose 1 or 2, which correspond to the first bottom surface echo and the second bottom surface echo, respectively; s 1 represents the normalized distance corresponding to the first bottom surface echo. s 2 represents the normalized distance corresponding to the second bottom surface echo; zLet be the one-way distance traveled by the ultrasonic wave from transmission to reception, corresponding to the _____. i The bottom surface echo value is 2. id ; f This refers to the ultrasonic testing frequency; a Let be the acoustic field radius of the ultrasonic transducer 4; Will s 1 and s 2. Substitute the diffraction loss coefficients obtained based on the Bessel function into the values ​​respectively. D ( s i The formula for calculating the diffraction coefficient is used to obtain the diffraction coefficient. D ( s 1) with D ( s 2): (4) In the formula, m The index variable for series summation; Reflectance coefficient R The calculation formula is: (5) In the formula, The acoustic characteristic impedance of the sample under test is 6. The acoustic characteristic impedance of the coupling agent is 5. ρ 1 and ρ 2 represents the density of the sample 6 and the coupling agent 5, respectively. c 1 and c 2 represents the sound velocity of the sample 6 and the coupling agent 5, respectively; Intrinsic sound attenuation coefficient α The formula for calculating 0 is: .

[0032] The intrinsic sound attenuation coefficient α 0 represents the accurate sound attenuation coefficient after system error correction.

[0033] Using the method of Example 2, with a thickness of d A 10 mm thick quartz glass sample (sample 6) was used as the test sample, and its acoustic attenuation coefficient at a frequency of 100 MHz was measured. The effective diameter of the ultrasonic transducer (sample 4) was 3 mm. The test was repeated 5 times, and the results are shown in Table 1.

[0034] Table 1: Test results of 10 mm thick quartz glass at 100 MHz (repeated 5 times)

[0035] As shown in Table 1, after systematically correcting for reflection loss and diffraction loss, the final intrinsic acoustic attenuation coefficient is... α0 is 0.173 ± 0.005 dB / cm, and the speed of sound c The value is 5900±100 m / s. This result exhibits low dispersion and good repeatability, verifying the accuracy and stability of the testing system of this invention under the thickness of a single test sample.

[0036] Using the method of Example 2, with a thickness of d Quartz glass with a thickness of 5-25 mm was used as the test sample 6, and its acoustic attenuation coefficient at a frequency of 100 MHz was tested. The effective diameter of the ultrasonic transducer 4 is 3 mm. The test sample 6 of each thickness was measured 5 times and the average value was taken. The results are shown in Table 2.

[0037] Table 2: Test results of sound attenuation coefficient of quartz glass of different thicknesses at 100 MHz (average value)

[0038] As shown in Table 2, the characteristic acoustic attenuation coefficients of samples of different thicknesses are... α The intrinsic acoustic attenuation coefficient (I) was 1.304 ± 1.238 dB / cm, indicating that it is significantly affected by sample thickness and fluctuates considerably. After loss correction, the intrinsic acoustic attenuation coefficient for samples of different thicknesses was... α The sound converges to 0.170 ± 0.006 dB / cm, and the velocity of sound... c 1 is 5900±100 m / s. The results show that the method of the present invention can still maintain high consistency and accuracy under different thickness conditions, verifying its applicability and reliability under different geometric conditions of the test samples.

Claims

1. A precise testing system for the high-frequency acoustic attenuation coefficient of acousto-optic materials, characterized in that, The system includes a pulse signal transmitting and receiving module, a signal processing and data display module, an ultrasonic transducer, a coupling agent, and a precision coupling device. The pulse signal transmitting and receiving module is communicatively connected to the signal processing and data display module and the ultrasonic transducer, respectively. The pulse signal transmitting and receiving module is configured to generate and process high-frequency electrical signals, output tunable electrical pulse excitation signals, and simultaneously receive and process ultrasonic echo electrical signals of the same frequency band and transmit them to the signal processing and data display module. The signal processing and data display module is configured to analyze and process the received ultrasonic echo signal, display the echo propagation time and voltage amplitude in real time, and support data recording and calculation result output. The ultrasonic transducer is configured to convert an electrical pulse signal into an ultrasonic signal and transmit it to the sample under test, while converting the ultrasonic echo signal reflected by the sample under test into an ultrasonic echo electrical signal and feeding it back to the pulse signal transmitting and receiving module. The coupling agent is coated between the ultrasonic transducer and the sample under test and is configured to reduce interfacial acoustic energy loss. The precision coupling device includes a helical side-rocking pressure control platform and a stage. The helical side-rocking pressure control platform can apply quantifiable axial pressure to the ultrasonic transducer and the sample under test while driving the stage to perform three-dimensional spatial pose adjustment, so that a stable thin-layer liquid coupling interface is formed between the ultrasonic transducer and the sample under test.

2. The precise testing system for the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 1, characterized in that, The tunable electrical pulse excitation signal is a tunable electrical pulse excitation signal with a center frequency of 20-200 MHz.

3. The precise testing system for the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 1, characterized in that, The center operating frequency of the ultrasonic transducer covers 20-200 MHz, and the -6 dB relative bandwidth is not less than 60%.

4. The precise testing system for the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 1, characterized in that, The coupling agent is a low-volatility liquid coupling medium.

5. A precise method for testing the high-frequency acoustic attenuation coefficient of acousto-optic materials using the system described in any one of claims 1-4, characterized in that, The steps of the testing method include: S1. Construct a precision coupling device and connect it to the pulse signal transmitting and receiving module, signal processing and data display module respectively. Power on, debug and initialize each module. S2. Select a thickness of d The sample to be tested is coated with a layer of coupling agent evenly on its surface and then placed on the stage. S3. Align and bond the ultrasonic transducer with the surface of the sample to be tested, which has been coated with coupling agent, and adjust the spiral side-rocking pressure control machine to apply coupling pressure to form a stable acoustic coupling interface; S4. Record the propagation time of the first bottom echo. t 1. Second bottom surface echo time t 2. First bottom surface echo voltage amplitude P 1 and the amplitude of the second bottom surface echo voltage P 2. And calculate the sound velocity of the sample under test based on the recorded data. c 1 and characterizing the sound attenuation coefficient α 1; S5. Based on Bessel function and normalized distance s i The diffraction loss coefficient was calculated. D ( s i ), and combined with the reflection coefficient R， Characterizing the sound attenuation coefficient α 1. Perform diffraction loss and reflection loss correction to obtain the intrinsic acoustic attenuation coefficient. α 0.

6. The method for accurately testing the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 5, characterized in that, In step S4, the sound velocity of the sample to be tested c The formula for calculating 1 is: 。 7. The method for accurately testing the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 5, characterized in that, In step S4, the acoustic attenuation coefficient of the sample under test is characterized. α The formula for calculating 1 is: 。 8. The method for accurately testing the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 5, characterized in that, In step S5, the distance is normalized based on the Bessel function. s i The diffraction loss coefficient was calculated. D ( s i The formula for calculating ) is: ， In the formula, i Choose 1 or 2, which correspond to the first bottom surface echo and the second bottom surface echo, respectively; s 1 represents the normalized distance corresponding to the first bottom surface echo. s 2 represents the normalized distance corresponding to the second bottom surface echo; m The index variable for summing a series.

9. The method for accurately testing the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 5, characterized in that, In step S5, the reflection coefficient R The calculation formula is: ， In the formula, The acoustic impedance of the sample under test. The acoustic impedance of the coupling agent. ρ 1 and ρ 2 represents the density of the sample to be tested and the coupling agent, respectively. c 1 and c 2 represents the sound velocity of the sample under test and the coupling agent, respectively.

10. The method for accurately testing the high-frequency acoustic attenuation coefficient of acousto-optic materials according to claim 5, characterized in that, In step S5, the intrinsic sound attenuation coefficient α The formula for calculating 0 is: 。

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