Wavefront modulation of water surface wave by a metasurface

Abstract

We design a planar metasurface to modulate the wavefront of a water surface wave (WSW) on a deep sub-wavelength scale. The metasurface is composed of an array of coiling-up-space units with specially designed parameters, and can take on the work of steering the wavefront when it is pierced into water. Like their acoustic counterparts, the modulation of WSW is ascribed to the gradient phase shift of the coiling-up-space units, which can be perfectly tuned by changing the coiling plate length and channel number inside the units. According to the generalized Snell's law, negative refraction and 'driven' surface mode of WSW are also demonstrated at certain incidences. Specially, the transmitted WSW could be efficiently guided out by linking a symmetrically-corrugated channel in 'driven' surface mode. This work may have potential applications in water wave energy extraction and coastal protection.

Unidirectional transmission of acoustic waves by using transmitted and reflected acoustic metasurfaces

“…18) The AMS is composed of two-dimensional artificial acoustic metamaterials with subwavelength thickness and can manipulate the acoustic waves. 18,[19][20][21][22][23][24] Zhu et al 18) demonstrated that an acoustic one-way open tunnel can be realized using an AMS to manipulate the trajectory of acoustic waves and that this tunnel can allow other substances to pass. Nevertheless, this system is limited by the low transmission contrast between two opposite directions.…”

Broadband reflected wavefronts manipulation using structured phase gradient metasurfaces

“…Besides, some researchers have demonstrated that the structure of coiling-up space or subwavelength corrugated surface can be used to design AMS with the phase change covering 0∼2π range. [12][13][14][15][16][17][18][19][20][21][22] And then some novel phenomena are demonstrated, such as the anomalous reflection and refraction, [12][13][14][15][16][17][18] and the planar acoustic axicon and lens. [19][20][21][22] Ding et al 23,24 have proposed that the split hollow sphere and double-split hollow sphere, as acoustic resonator, can be also used to construct AMS.…”