2016/10/13 by Noé Jiménez, Vicent Romero-García, Vincent Pagneux +1 · 1 citation
Physics and Astronomy · #physics.class-ph
paper · pdf · doi:10.1103/physrevb.95.014205
published as Physical Review B, 95, pp. 014205, (2017)
arxiv created 2016/10/13 · arxiv updated 2019/10/16
We theoretically and experimentally report sub-wavelength resonant panels for low-frequency quasi-perfect sound absorption including transmission by using the accumulation of cavity resonances due to the slow sound phenomenon. The sub-wavelength panel is composed of periodic horizontal slits loaded by identical Helmholtz resonators (HRs). Due to the presence of the HRs, the propagation inside each slit is strongly dispersive, with near-zero phase velocity close to the resonance of the HRs. In this slow sound regime, the frequencies of the cavity modes inside the slit are down-shifted and the slit behaves as a subwavelength resonator. Moreover, due to strong dispersion, the cavity resonances accumulate at the limit of the bandgap below the resonance frequency of the HRs. Near this accumulation frequency, simultaneously symmetric and antisymmetric quasi-critical coupling can be achieved. In this way, using only monopolar resonators quasi-perfect absorption can be obtained in a material including transmission.