通过快速调制分层介质实现宽带声学亚波长成像。

Broadband acoustic subwavelength imaging by rapidly modulated stratified media.

作者信息

Zhu Xing-Feng, Wei Qi, Wu Da-Jian, Liu Xiao-Jun

机构信息

Key Laboratory of Modern Acoustics, Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.

Jiangsu Key Lab on Opto-Electronic Technology, School of Physics and Technology, Nanjing Normal University, Nanjing, 210023, China.

出版信息

Sci Rep. 2018 Mar 21;8(1):4934. doi: 10.1038/s41598-018-23411-5.

DOI:10.1038/s41598-018-23411-5

PMID:29563564

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5862972/

Abstract

An acoustic anisotropic lens (AAL) based on large mass-density modulation depth (LMMD) medium is proposed for subwavelength imaging. The underlying mechanism for converting evanescent components into propagating waves is attributed to the strong suppression of the transverse velocity field component in LMMD medium. In addition, the proposed lens can operate in a broadband manner, which is more flexible in practical applications. Both transfer matrix method and finite element method are used to corroborate the subwavelength imaging capabilities of the proposed lens. The numerical simulations demonstrate that the proposed lens can clearly distinguish two Gaussian sources with equal width of λ/25 and separation of λ/5 in a broad frequency bandwidth. Medium losses decrease the transmission but cannot compromise the resolution of the lens.

摘要

提出了一种基于大质量密度调制深度（LMMD）介质的声学各向异性透镜（AAL）用于亚波长成像。将倏逝分量转换为传播波的潜在机制归因于LMMD介质中横向速度场分量的强烈抑制。此外，所提出的透镜可以以宽带方式工作，这在实际应用中更加灵活。采用传输矩阵法和有限元法来证实所提出透镜的亚波长成像能力。数值模拟表明，所提出的透镜在很宽频率带宽内能够清晰区分宽度为λ/25且间距为λ/5的两个高斯源。介质损耗会降低透射率，但不会影响透镜的分辨率。