Measurement of Low-Frequency Ultrasonic Waves by Fraunhofer Diffraction.
Measurement of Low-Frequency Ultrasonic Waves by Fraunhofer Diffraction.
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通过夫琅和费衍射测量低频超声波。
DOI：
10.1143/jjap.33.3110
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发表时间：
1994
影响因子：
1.5
通讯作者：
M. Akazaki
中科院分区：
文献类型：
--
作者：
Y. Sonoda;M. Akazaki
本文从理论和实验上研究了在等离子体核聚变研究装置中识别长波等离子体波或涨落的新方法--夫琅和费衍射法在测量空气中低频超声波中的应用。实验证明，波数约为0.1至0.74 mm-1的波可以通过使用可见激光检测。这样的波数对应于0.6至4.3mdeg的衍射角，其比通过常规衍射方法测量的标准值小得多。此外，它表明，如果采用发散探测光束，波的位置可以通过测量衍射波的空间相位分布来识别。
The application of the Fraunhofer diffraction method, which has been developed as a new means to identify long-wavelength plasma waves or fluctuations appearing in plasma nuclear fusion research machines, to the measurement of low-frequency ultrasonic waves propagating in air was theoretically and experimentally examined. It is experimentally demonstrated that a wave with a wave number of about 0.1 to 0.74 mm-1 can be detected by using a visible laser. Such a wave number corresponds to a diffraction angle of 0.6 to 4.3 mdeg, which is much smaller than the standard value measured by the conventional diffraction method. Furthermore, it is shown that if a diverging probe beam is adopted, the wave position can be identified by measuring the spatial phase distribution of the diffracted wave.