Ultra-broadband asymmetric acoustic transmission in a straight open duct

摘要

We propose a mechanism of broadband asymmetric acoustic transmission in a 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.