We propose a mechanism of broadband asymmetric acoustic transmission in straight open duct, by breaking spatial symmetry using two geometrically-asymmetric components filled with natural material placed on two sides of duct. Thanks to low loss and dispersion of natural material, the resulting device enables high-efficiency and ultra-broadband transmission for plane waves coming from one port while maintaining an open passage for light, heat and background fluid. Our design with simplicity, ultra-lightweight, optical and thermal transparency and ventilating functionality opens up possibility for novel acoustic one-way devices and may have potential in diverse applications such as duct noise control.

中文翻译：

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直开式管道中的超宽带非对称声学传输

我们提出了一种在直开式管道中宽带非对称声学传输的机制，通过使用放置在管道两侧的填充天然材料的两个几何不对称组件打破空间对称性。由于天然材料的低损耗和低色散，由此产生的设备能够对来自一个端口的平面波进行高效和超宽带传输，同时保持光、热和背景流体的开放通道。我们的设计具有简单、超轻、光学和热透明性以及通风功能，为新型声学单向设备开辟了可能性，并可能在管道噪声控制等多种应用中具有潜力。