Lin Sz-Chin Steven, Tittmann Bernhard R, Huang Tony Jun
J Appl Phys. 2012 Jun 15;111(12):123510. doi: 10.1063/1.4729803. Epub 2012 Jun 19.
This article reports the design concept of a novel acoustic beam aperture modifier using butt-jointed gradient-index phononic crystals (GRIN PCs) consisting of steel cylinders embedded in a homogeneous epoxy background. By gradually tuning the period of a GRIN PC, the propagating direction of acoustic waves can be continuously bent to follow a sinusoidal trajectory in the structure. The aperture of an acoustic beam can therefore be shrunk or expanded through change of the gradient refractive index profiles of the butt-jointed GRIN PCs. Our computational results elucidate the effectiveness of the proposed acoustic beam aperture modifier. Such an acoustic device can be fabricated through a simple process and will be valuable in applications, such as biomedical imaging and surgery, nondestructive evaluation, communication, and acoustic absorbers.
本文报道了一种新型声束孔径调制器的设计概念，该调制器采用对接梯度折射率声子晶体（GRIN PCs），由嵌入均匀环氧树脂基体中的钢圆柱体组成。通过逐渐调整GRIN PC的周期，声波的传播方向可以在结构中连续弯曲，以遵循正弦轨迹。因此，通过改变对接GRIN PCs的梯度折射率分布，可以缩小或扩大声束的孔径。我们的计算结果阐明了所提出的声束孔径调制器的有效性。这种声学装置可以通过简单的工艺制造，在生物医学成像和手术、无损检测、通信和吸声器等应用中具有重要价值。
