Hybrid membrane resonators with fluid permeable cavity

Abstract

We report the design and the experimental realization of perfect absorption of acoustic waves by a hybrid membrane resonator with air permeable membranes and demonstrate that hybrid membrane resonators with a leaky cavity can also achieve perfect absorption. We further increase the leakage of the cavity by opening small holes on the back wall of the cavity and demonstrate how the high absorption of the device could be restored by changing the cavity volume. The device so created has one surface being very low reflection and the other being high reflection, while maintaining good transmission, making it a good candidate for devices with a large Willis coefficient as well.