Acoustic Focusing and Energy Confinement Based on Multilateral Metasurfaces

The authors describe a $c{{0}{0ex}}o{{0}{0ex}}i{{0}{0ex}}l{{0}{0ex}}i{{0}{0ex}}n{{0}{0ex}}g-u{{0}{0ex}}p-s{{0}{0ex}}p{{0}{0ex}}a{{0}{0ex}}c{{0}{0ex}}e$ approach to harvesting energy from ubiquitous, ambient low-frequency sound. They design multilateral metasurfaces composed of a labyrinthine series, for acoustic focusing and energy confinement. Control of the first reflection, coupling effects, and multiple reflections between and among the metasurfaces are discussed.