The control of sound propagation and reflection has always been the goal of engineers involved in the design of acoustic systems. A recent design approach based on coordinate transformations, which is applicable to many physical systems, together with the development of a new class of engineered materials called metamaterials, has opened the road to the unconstrained control of sound. However, the ideal material parameters prescribed by this methodology are complex and challenging to obtain experimentally, even using metamaterial design approaches. Not surprisingly, experimental demonstration of devices obtained using transformation acoustics is difficult, and has been implemented only in two-dimensional configurations. Here, we demonstrate the design and experimental characterization of an almost perfect three-dimensional, broadband, and, most importantly, omnidirectional acoustic device that renders a region of space three wavelengths in diameter invisible to sound.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1038/nmat3901 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Stable Self-Powered Broadband PtSe/Si Pin Infrared Photodetector Based on a High-Quality Ultrapure Intrinsic Si Film Exfoliated by Si/SOI Wafer Bonding.
ACS Appl Mater Interfaces
January 2025
College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Zhangzhou 363000, China.
Article Synopsis
- The study focuses on enhancing the performance of PtSe in photodetectors by utilizing hydrophobic bonding for high-quality n-Si/SOI wafer bonding.
- The resulting p-PtSe/i-Si/n-Si pin photodetector exhibits impressive spectral detection (532 to 2200 nm) and a high rectification ratio (2.1 × 10), indicating effective device functionality.
- This research represents a novel method for merging wafer bonding techniques with 2D material transfer, paving the way for improved Si-based photodetector designs.
Dynamic 3D metasurface holography via cascaded polymer dispersed liquid crystal.
Microsyst Nanoeng
December 2024
College of Optical and Electronic Technology, China Jiliang University, Hangzhou, 310018, China.
Metasurface with natural static structure limits the development of dynamic metasurface holographic display with rapid response and broadband. Currently, liquid crystal (LC) was integrated onto the metasurface to convert the passive metasuface into an active one. But, majority of LC-assisted active metasurfaces often exhibit trade-offs among degree of freedom (DoF, typically less than 2), information capacity, response speed, and crosstalk.
View Article and Find Full Text PDFAcoustic modeling of three-dimensional-printed fibrous sound absorbersa).
J Acoust Soc Am
December 2024
Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, Michigan 49931, USA.
In this study, an analytical model was developed to predict the sound absorption performance of fibrous absorbers fabricated using an extrusion-based three-dimensional (3D) printing method. The proposed model employs geometric design parameters, including the average fiber diameter and the horizontal and vertical fiber separations, to calculate the porosity, static airflow resistivity, tortuosity, and viscous and thermal characteristic lengths. These transport parameters are then used within the Johnson-Champoux-Allard semiempirical formulation to predict the normal incidence sound absorption coefficient.
View Article and Find Full Text PDFSwitchable 3D Photonic Crystals Based on the Insulator-to-Metal Transition in VO.
ACS Appl Mater Interfaces
December 2024
Center for Hybrid Nanostructures, Universität Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany.
Article Synopsis
- Photonic crystals (PhCs) are optical structures that manipulate light by creating a photonic band gap (PBG) through their dielectric properties, traditionally fixed and static.
- Recent advancements target switchable PhCs, especially using vanadium dioxide (VO), which changes its state and optical properties near room temperature, allowing for a reversible adjustment of the PBG.
- This research introduces a fabrication method for 3D switchable VO photonic crystals, demonstrating significant control over PBG at specific wavelengths in the near-infrared region, paving the way for versatile photonic devices that can adapt their functionalities.
In this paper, a novel thermo-optic metagrating based on phase-change material (vanadium dioxide, VO) is proposed for broadband, polarization-independent, and non-dispersive transmission modulation at the telecommunication wavelengths. In the pursuit of concurrent attainment of multiple performance objectives, nanostructured VO metagratings are optimized numerically using inverse design algorithms. Notably, adjoint optimization pertaining to both phases of VO facilitates better modulation capabilities within free-form shaped VO metagratings compared to shape-optimized methods with predetermined designs.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!