2023-05-31 スイス連邦工科大学ローザンヌ校(EPFL)
◆この技術は、従来の膜を使用するスピーカーと比べて効率的で、幅広い周波数範囲で動作可能です。EPFLは、この概念を活用した革新的なノイズ低減ソリューションの開発において、オーディオテクノロジー企業のSonexos SAと提携しています。
＜関連情報＞
- https://actu.epfl.ch/news/actively-reducing-noise-by-ionizing-air-2/
- https://www.nature.com/articles/s41467-023-38522-5#citeas
サブ波長プラズマ音響メタレイヤーで超広帯域音響制御を実現 Ultrabroadband sound control with deep-subwavelength plasmacoustic metalayers
Stanislav Sergeev,Romain Fleury & Hervé Lissek
Nature Communications Published:19 May 2023
DOIhttps://doi.org/10.1038/s41467-023-38522-5
Abstract
Controlling audible sound requires inherently broadband and subwavelength acoustic solutions, which are to date, crucially missing. This includes current noise absorption methods, such as porous materials or acoustic resonators, which are typically inefficient below 1 kHz, or fundamentally narrowband. Here, we solve this vexing issue by introducing the concept of plasmacoustic metalayers. We demonstrate that the dynamics of small layers of air plasma can be controlled to interact with sound in an ultrabroadband way and over deep-subwavelength distances. Exploiting the unique physics of plasmacoustic metalayers, we experimentally demonstrate perfect sound absorption and tunable acoustic reflection over two frequency decades, from several Hz to the kHz range, with transparent plasma layers of thicknesses down to λ/1000. Such bandwidth and compactness are required in a variety of applications, including noise control, audio-engineering, room acoustics, imaging and metamaterial design.
