Ash B J, Worsfold S R, Vukusic P, Nash G R
College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QF, UK.
Nat Commun. 2017 Aug 2;8(1):174. doi: 10.1038/s41467-017-00278-0.
Surface acoustic wave (SAW) devices are widely used for signal processing, sensing and increasingly for lab-on-a-chip applications. Phononic crystals can control the propagation of SAW, analogous to photonic crystals, enabling components such as waveguides and cavities. Here we present an approach for the realisation of robust, tailorable SAW phononic crystals, based on annular holes patterned in a SAW substrate. Using simulations and experiments, we show that this geometry supports local resonances which create highly attenuating phononic bandgaps at frequencies with negligible coupling of SAWs into other modes, even for relatively shallow features. The enormous bandgap attenuation is up to an order-of-magnitude larger than that achieved with a pillar phononic crystal of the same size, enabling effective phononic crystals to be made up of smaller numbers of elements. This work transforms the ability to exploit phononic crystals for developing novel SAW device concepts, mirroring contemporary progress in photonic crystals.The control and manipulation of propagating sound waves on a surface has applications in on-chip signal processing and sensing. Here, Ash et al. deviate from standard designs and fabricate frequency tailorable phononic crystals with an order-of-magnitude increase in attenuation.
表面声波（SAW）器件广泛应用于信号处理、传感领域，并且越来越多地应用于芯片实验室应用中。声子晶体可以控制表面声波的传播，类似于光子晶体，能够实现诸如波导和腔体等组件。在此，我们提出一种基于在SAW衬底上图案化环形孔来实现坚固且可定制的SAW声子晶体的方法。通过模拟和实验，我们表明这种几何结构支持局部共振，即使对于相对较浅的特征，也能在频率上产生高度衰减的声子带隙，同时表面声波与其他模式的耦合可忽略不计。巨大的带隙衰减比相同尺寸的柱形声子晶体所实现的衰减大一个数量级，使得有效的声子晶体可以由更少数量的元件组成。这项工作改变了利用声子晶体开发新型SAW器件概念的能力，反映了光子晶体领域的当代进展。对表面上传播的声波进行控制和操纵在芯片上的信号处理和传感方面具有应用价值。在此，阿什等人偏离了标准设计，制造出衰减增加一个数量级的频率可定制声子晶体。
