Acoustic transparency and slow sound using detuned acoustic resonators

We demonstrate that the phenomenon of acoustic transparency and slow sound propagation can be realized with detuned acoustic resonators (DAR), mimicking thereby the effect of electromagnetically induced transparency (EIT) in atomic physics. Sound propagation in a pipe with a series of side-attached DAR, with adjacent DAR units spaced by a distance much smaller than the wavelength, is analyzed. We show that such a chain of DAR units forms an analog of one-dimensional (1D) metamaterial with unique properties of dispersion and transmission, revealing the possibility of slowing sound (at 2 kHz) down by {~}100 times within the 40-Hz-broad transparency window. Preliminary experiments with two resonators detuned from the central frequency of 1.2 kHz verify the occurrence of the transparency effect.