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Title: | 布拉格光柵光纖於光聲量測系統之設計開發 Design and Development of Photoacoustic Measurement System Using Fiber Bragg Grating |
Authors: | 劉家豪 Jia-Hao Liou |
Advisor: | 黃光裕 Kuang-Yuh Huang |
Keyword: | 光聲成像技術,FBG布拉格光柵光纖,超音波感測器,能量調變法, Photoacoustic imaging technology,Fiber Bragg Grating (FBG),Ultrasonic sensor,Energy modulation method, |
Publication Year : | 2024 |
Degree: | 碩士 |
Abstract: | 光聲量測技術(Photoacoustic)常應用於非接觸性的物體測量,此種非侵入式的量測方式能大幅降低對待測物的傷害,使用光源激發待測物引起振動或變形進而發出超聲波,提供有關待測物形狀、內部構造或振動頻率等訊息。現行的光聲量測系統多使用壓電式的量測裝置,雖然有較好的聲學響應,但容易受到外部電場與磁場的干擾,體積也較為龐大。因此,本研究旨在設計和開發一種基於布拉格光柵的光聲測量系統,用於非接觸式測量物體表面的聲學振動。該系統利用布拉格光柵的繞射原理,接收布拉格光柵光纖反射回的光強變化,實現了高靈敏度和高精度的聲學測量,可以應用於材料科學、生物醫學、機械工程等領域。在定頻測時實驗中,分別在空氣中與水中進行性能測試,結果顯示Fiber Bragg Grating (FBG)量測系統在水中具有較佳的訊噪比,其適用頻寬可達數MHz。使用脈衝電弧產生隨機頻率聲源進行測試,FBG量測系統亦能有效接收並分析其頻譜,與市售壓電超音波感測器有相似量測結果。在光聲成像部分,設計非共軸式和共軸式兩種激發裝置,共軸式的裝置激發與聲音接收在同一軸線上,量測效果較理想。使用波長532 nm的脈衝雷射激發樣本,進行一維和二維的光聲掃瞄,電壓響應差異可有效分辨出組織中不同質地的位置。 Photoacoustic measurement technology is commonly applied in non-contact object measurement. This non-invasive measurement method significantly reduces damage to the test object. It involves using light sources to excite the test object, causing vibration or deformation and emitting ultrasonic waves. This provides information about the shape, internal structure, or vibration frequency of the test object. Current photoacoustic measurement systems often use piezoelectric devices, which despite having better acoustic response, are susceptible to interference from external electric and magnetic fields and have a larger volume. Therefore, this study aims to design and develop a photoacoustic measurement system based on a Fiber Bragg Grating (FBG). This system is intended for non-contact measurement of the acoustic vibration on the surface of objects. The system utilizes the diffraction principle of FBG, receiving changes in light intensity reflected. This achieves high sensitivity and precision in acoustic measurement and can be applied in fields such as materials science, biomedical science, and mechanical engineering. In experiments conducted for frequency measurement, performance tests were carried out in both air and water. The results show that the FBG measurement system has better signal-to-noise ratio in water, with an applicable bandwidth of several megahertz. Testing with a pulsed electric arc generating a random frequency sound source demonstrated the FBG measurement system was able to effectively receive and analyze its spectrum. The measurement results were similar to those obtained with commercially available piezoelectric ultrasonic sensors. In the aspect of photoacoustic imaging, two types of excitation devices were designed, non-coaxial and coaxial. The coaxial configuration, where excitation and sound reception occur on the same axis, yielded more favorable measurement results. One-dimensional and two-dimensional photoacoustic scans measurement were performed by using a pulsed laser with a wavelength of 532 nm to excite the sample. Differences in voltage response effectively distinguished positions with different textures within the tissue. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/91373 |
DOI: | 10.6342/NTU202400079 |
Fulltext Rights: | 未授權 |
Appears in Collections: | 機械工程學系 |
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ntu-112-1.pdf Restricted Access | 5.99 MB | Adobe PDF |
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