Extraordinary optical transmissions through metallic films with arrays of subwavelength holes have attracted much attention in the past few years, and surface plasmons are accepted as the key factor in their origin. Further studies showed that the abilities of surface plasmons can also be extended to achieve light collimation. Here, we show that collective surface oscillation can also occur in acoustics, and different from previous reports, we demonstrate that extraordinary acoustic transmissions and sound collimation can be achieved when the wavelength is much longer than the characteristic length of the sample. The excitation and detection approaches of the acoustic surface oscillation are also presented. Our findings should open up prospects for acoustic applications, and many exotic optical phenomena related to surface plasmons can be anticipated with their counterparts in acoustics.

• Received 20 August 2014

DOI:https://doi.org/10.1103/PhysRevB.92.104105