Figure 1: Schematic of metamaterial-enhanced acoustic sensing.
Top: the pressure field of sound is spatially compressed and amplified inside the high-refractive-index acoustic metamaterial before being detected by a sensor. Bottom: schematic metamaterial dispersion curve for acoustic waves with a high-k state. In such a metamaterial medium, sound propagation with a large wave vector k (measured by wave number) is enabled, rendering an effective high-refractive-index neff=kz/kair.
