Multiphysical Digital Coding Metamaterials for Independent Control of Broadband Electromagnetic and Acoustic Waves with a Large Variety of Functions

Abstract

Fabricating materials with customized characteristics for both electromagnetic (EM) and acoustic waves remain a significant challenge using the current technology, since the demand of multiphysical manipulation requires a variety of material parameters that are hard to satisfy in nature. However, the emergence of artificially structured materials provides a new degree of freedom to tailor the wave–matter interactions in dual physical domains at the subwavelength scale. Here, a bifunctional digital coding metamaterial (MM) is proposed to engineer the propagation behaviors of EM and acoustic waves simultaneously and independently. Four kinds of rigid pillars with various material properties are employed to serve as 1-bit reflection-type digital meta-atoms with antiphase responses in both frequency spectra, thus offering the opportunities for independent field control as desired. The MM demonstrates excellent performance of scattering manipulations from 5700 to 8000 Hz in the acoustic region and 5.80–6.15 GHz in the microwave region. The bifunctional MM is verified through full-wave simulations and experimental measurements with good agreement, which stands out as a powerful tool for related applications in the future.

Ultrathin Electromagnetic–Acoustic Amphibious Stealth Coats

“…[ 43 ] By intricately selecting and optimizing the material properties and structure dimensions, researchers have explored the standard way to fabricate multiphysical devices. [ 36–41,43,44 ] For the biphysical devices which could control the responses of the electromagnetic and acoustic wave, the customized permittivity, permeability, bulk modulus, and mass density of the material are all required for specific electromagnetic and acoustic applications. [ 40 ] By choosing the PDMS with air bubbles which would achieve underwater acoustic absorption as the insulating layer of the MIM configuration, the difficulty of the compatibility of the two system could be tackled.…”

“…Microwave and acoustic wave are two common sources for object detection, which may be mutually employed in practice. There are some works about biphysical metamaterials that can manipulate free‐space electromagnetic and free‐space acoustic waves simultaneously such as cloaks, [ 36,37 ] coding devices, [ 38–40 ] absorber, or insulation devices. [ 40–42 ] The device which incorporates a membrane decorated with ultrathin indium tin oxide (ITO) microwave ring resonators and another membrane covered by a continuous ultrathin ITO film proposed by Song et al in 2018 could attain simultaneous over 85% microwave absorptivity from 7 to 14 GHz and preferable sound transmission loss from 100 to 1000 Hz.…”

Real-time terahertz meta-cryptography using polarization-multiplexed graphene-based computer-generated holograms

“…With strong competitiveness in construction of more efficient, more functional, easier-to-fabricate, and easierto-integrate holograms from microwave to terahertz (THz) spectra, metasurfaces as 2D arrays of sub-wavelength scatterers [4][5][6], have recently grabbed considerable attention of the physics and optics research communities owing to unprecedented flexibility in arbitrary manipulation of phase [7,8], amplitude [9,10], polarization [11], and shape [12] of the local electromagnetic (EM) fields with less energy dissipation. Metasurfaces have become a rapidly growing field of research in recent years due to their exceptional abilities in various modern applications like absorbing meta-devices [13], antenna engineering [14], Bessel beam generation [15], wavefront shaping [16], and intelligent imaging/recognizing [17].…”

Magnetic–acoustic biphysical invisible coats for underwater objects

“…This consideration is valid for a far-field, single-station wave characterization system, but not suitable for a near-field system, including the magnetic field probe. There are some works about dual-physics metasurfaces that can manipulate electromagnetic and acoustic waves simultaneously 31,32 . However, magnetic-acoustic biphysical invisible coats for underwater objects have not been explored before.…”