Tunable Non-Hermitian Acoustic Filter

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