Issue |
EPL
Volume 124, Number 3, November 2018
|
|
---|---|---|
Article Number | 34001 | |
Number of page(s) | 5 | |
Section | Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics | |
DOI | https://doi.org/10.1209/0295-5075/124/34001 | |
Published online | 27 November 2018 |
𝒫𝒯 symmetric sonic crystals: From asymmetric echoes to supersonic speeds
Department of Physics, Universidad Carlos III de Madrid - Avenida de la Universidad, 28911 Leganés (Madrid), Spain
(a) johan.christensen@uc3m.es (corresponding author)
Received: 3 September 2018
Accepted: 26 October 2018
Parity-time 𝒫𝒯 symmetric structures based on balanced distributions of gain and loss have attracted significant attention in acoustic metamaterial research since they allow one to sculpture the flow of sound waves in complete new ways. We compute complex Bloch waves in fluidic non-Hermitian sonic crystals and demonstrate how band coalescence can lead to exceptionally large group velocities permitting supersonic wave propagation in 𝒫𝒯 symmetric slabs. Further, by controlling the degree of non-hermiticity in such systems, we found that asymmetrically reflected pulses can be readily amplitude-tuned, which might find potential use in echocardiography, sonar and echo suppressors.
Key words:
© EPLA, 2018
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