Perfect and broadband acoustic absorption by critically coupled sub-wavelength resonators

• DOI: 10.1038/srep19519
• Publication Date: 2016-01-19T10:09:53Z
• Authors: V. Romero-García; G. Theocharis; O. Richoux; A. Merkel; V. Tournat; V. Pagneux
• Keywords: Helmholtz free energy; Helmholtz resonator; Sound energy; Leakage (economics)

Abstract Perfect absorption is an interdisciplinary topic with a large number of applications, the challenge which consists broadening its inherently narrow frequency-band performance. We experimentally and analytically report perfect broadband for audible sound, by mechanism critical coupling, sub-wavelength multi-resonant scatterer (SMRS) made plate-resonator/closed waveguide structure. In order to introduce role key parameters, we first present case single resonant (SRS) Helmholtz resonator/closed both cases controlled balance between energy leakage several resonances inherent losses system leads peaks. SMRS show that systems can be critically coupled using leakage. particular, in system, thickness λ/12 diameter λ/7, peaks overlap produce bigger than 93% frequencies extend over factor 2 frequencies. The reported concepts methodology provide guidelines design absorbers could contribute solve major issue noise reduction.