Tunable Non-Hermitian Acoustic Filter

We propose, design, and experimentally test a non-Hermitian acoustic superlattice that acts as a tunable precise filter. The superlattice is composed of two concatenated sublattices. The first sublattice is Hermitian, while the other can be adjusted to be Hermitian or non-Hermitian. The existence of non-Hermiticity, in terms of an induced loss in the second sublattice, results in the generation of absorption resonances that appear in the reflected spectrum. This provides us with a powerful knob to absorb or reflect several frequencies at will with high accuracy. The number of filtered frequencies can be controlled by designing the resonances in the first sublattice. Our proposed tunable acoustic filter can be extended to higher-frequency ranges, such as ultrasound, and other areas, such as photonics.

Automated summary

Researchers have proposed and tested a non-Hermitian acoustic superlattice that functions as a tunable precise filter, where the second sublattice's properties can be adjusted to absorb or reflect multiple frequencies with high accuracy.