title: Super-resolution imaging by resonant tunneling in anisotropic acoustic metamaterials.
abstract: The resonant tunneling effects that could result in complete transmission of evanescent waves are examined in acoustic metamaterials of anisotropic effective mass. The tunneling conditions are first derived for the metamaterials composed of classical mass-in-mass structures. It is found that the tunneling transmission occurs when the total length of metamaterials is an integral number of half-wavelengths of the periodic Bloch wave. Due to the local resonance of building units of metamaterials, the Bloch waves are spatially modulated within the periodic structures, leading to the resonant tunneling occurring in the low-frequency region. The metamaterial slab lens with anisotropic effective mass is designed by which the physics of resonant tunneling and the features for evanescent field manipulations are examined. The designed lens interacts with evanescent waves in the way of the propagating wavenumber weakly dependent on the spatial frequency of evanescent waves. Full-wave simulations validate the imaging performance of the proposed lens with the spatial resolution beyond the diffraction limit.
authors.affiliation: Key Laboratory of Dynamics and Control of Flight Vehicle, Ministry of Education and School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Liu
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhou
authors.forename: Guoliang
authors.initials: G
authors.lastname: Huang
authors.forename: Gengkai
authors.initials: G
authors.lastname: Hu
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D016880:Anisotropy; D003198:Computer Simulation; D004867:Equipment Design; D007909:Lenses; D008027:Light; D008420:Manufactured Materials; D008962:Models, Theoretical; D009716:Numerical Analysis, Computer-Assisted; D055095:Optics and Photonics / Q000295:instrumentation*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D014732:Vibration