Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2014 Nov 13;4:7038. doi: 10.1038/srep07038

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright © 2014, Macmillan Publishers Limited. All rights reserved

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder in order to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0/

PMC Copyright notice

(a) The illustration of the trapped-rainbow device, containing an oblique air waveguide attached with 30 space-coiling units of different depth. The acoustic wave is incident along x direction from the left side. (b) The zoomed-in illustration of the bottom-left space-coiling unit. The blue arrows show the effective propagation path of the acoustic waves inside the space-coiling unit. (c) The simplified model with effective medium, calculated to compare with the results obtained by the space-coiling structures. (d) The frequency dependence of the effective refractive index n of the effective medium.