Real-Time Demultiplexer for Mixed-Frequency Acoustic Signals

To achieve real-time frequency-division multiplexing for mixed-frequency acoustic signals and instantaneous information transmission, we present a demultiplexer based on a coiled labyrinth structure by means of spatial demultiplexing. The structure is composed of six coiled channels of varying lengths, embedded in the wall of the waveguide at a subwavelength scale. Leveraging localized resonance characteristics, the device separates and traps acoustic waves of different frequencies within specific channels. Unlike conventional rainbow trapping primarily aimed at energy dissipation, this design directly enables mixed-frequency acoustic signal demultiplexing, harnessing the intrinsic frequency-space mapping for information decoding. Numerical simulations demonstrate that the six distinct frequency components of the acoustic signal are guided into different curled channels, facilitating spectral demultiplexing. This physical separation is the basis for information transmission, a capability that extends to the efficient transfer of digital image data. Despite its low structural complexity and compact footprint, the device retains the capability to demultiplex multi-frequency acoustic signals and achieves high-performance signal transmission. Moreover, demultiplexing is performed instantaneously by the device without additional digital signal processing, embodying the “structure-as-function” design philosophy. This paradigm offers a novel approach to acoustic materials for information transmission and signal processing, heralding the prospect of their practical application in real-time acoustic communication.