A magnetically controlled tunable acoustic super-resolution lens

¹ A State Key Laboratory for Turbulence and Complex Systems, Beijing Key Laboratory of Magnetoelectric Materials and Devices (BKL- MEMD), College of Engineering, Peking University - Beijing 100871, China
² A Energy Saving & Environmental Protection & Occupational Safety and Health Research Institute, China Academy of Railway Sciences Corporation Limited - Beijing 100871, China

^(a) pieym@pku.edu.cn

Received: 21 July 2019
Accepted: 31 October 2019

Abstract

Acoustic artificial structures have attracted much attention in recent decades due to their unique acoustic handling characteristics. The lightweight, easy-to-design feature and low cost of the thin-film acoustic artificial structure make it a great advantage in achieving super-resolution imaging and device miniaturization. However, since the film-type lens achieves super-resolution only at the resonance frequency, the frequency band in which it operates is greatly limited. In this work, considering the complexity of the vibration problem of the additional mass film, we propose a simple zero-mass method to design the operating frequency of the film-type prism. After that, a magnetic-field-controlled thin-film acoustic super-prism with a size of only six percent of the wavelength at working frequency is designed. Subsequently, based on the mechanism of magnetically induced stress, it achieves the super-resolution imaging within a frequency range from 350 Hz to 700 Hz. It provides a new idea for the design of an acoustic super-prism, and potential applications can be expected in acoustic imaging.