Manipulation of acoustic wavefront by transmissive metasurface based on pentamode metamaterials

• 来源期刊: 中国物理B（英文版）
• 关键词: metasurface frequency-independent pentamode high transmission
• 年，卷（期）: 2019,（2）
• 页码范围: 302-308
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-1056/28/2/024301

摘要

An underwater acoustic metasurface with sub-wavelength thickness is designed for acoustic wavefront manipulation. In this paper, a pentamode lattice and a frequency-independent generalized acoustic Snell's law are introduced to overcome the limitations of narrow bandwidth and low transmittance. The bulk modulus and effective density of each unit cell can be tuned simultaneously, which are modulated to guarantee the achievement of refractive index profile and high transmission. Here, we actualize anomalous refraction, generation of non-diffracting Bessel beam, sub-wavelength flat focusing, and surface wave conversion by constructing inhomogeneous acoustic metasurface. This design approach has potential applications in medical ultrasound imaging and underwater acoustic communications.