Generation and Directivity Control of Bulk Acoustic Waves by Phase Velocity Scanning of Laser Interference Fringes
Generation and Directivity Control of Bulk Acoustic Waves by Phase Velocity Scanning of Laser Interference Fringes
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激光干涉条纹相速度扫描体声波的产生和方向性控制
DOI：
10.1143/jjap.34.2874
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
K. Yamanaka
中科院分区：
文献类型：
--
作者：
H. Nishino;Y. Tsukahara;Hideo Cho;Y. Nagata;T. Koda;K. Yamanaka
提出了一种利用扫描干涉条纹产生高频体声波的新方法。SIF是由两束不同频率的相干激光在不透明的样品上相交而产生的。通过这种方法可以产生单向的体声波并传播到样品中。声表面波与声表面波波前的位相匹配条件决定了声表面波的传播方向，而声表面波的位相匹配条件可由激光入射角度控制。文中描述了该方法的原理，并用Si3N4烧结样品进行了实验验证。实验用15 mJ/130 ns调Q的Nd：YAG激光器产生80 MHz的BAW，用50 mW的Ar离子连续激光用光学刀口法进行检测。通过改变激光入射角度从0.066°到0.136°，使体声表面波的方向性从24.5°变为77.5°。BAW的准直性很好，尤其是在近场。
A novel method for generating high-frequency bulk acoustic waves (BAW) using scanning interference fringes (SIF) is presented. The SIF are produced by intersecting two coherent laser beams with different frequencies on an opaque specimen. It is possible to generate unidirectional BAW which propagate into the specimen by this method. Propagation direction of the BAW is determined by the phase-matching condition between the SIF and the wave front of the BAW at the surface, which could be controlled by incident angles of laser beams. The principle of this method and experimental verification using a sintered Si3N4 specimen are described. Experiments were carried out using a 15 mJ/130 ns Q-switched Nd:YAG laser for 80 MHz BAW generation and optical knife-edge method with 50 mW argon-ion CW laser for detection. Directivity of BAW was steered from 24.5° to 77.5° by changing the incident angles of the laser beams from 0.066° to 0.136°. BAW were found to be well collimated especially in the near field.