Experimental determination for resonance-induced transmission of acoustic waves through subwavelength hole arrays

We measured acoustic transmissions through subwavelength hole arrays fabricated on brass plates at normal and oblique incidence. It is found experimentally that the transmission phenomena for the hole array in thin plate case are analogous to the previously observed enhanced transmission of electromagnetic waves [Ebbesen , Nature (London) 391, 667 (1998)]. While for the hole array in thick plate case, the transmission peaks of acoustic wave occur well below Wood's anomalies, and the spectrum characteristics reveal a Fabry-Perot-like resonance. An effective fluid approach is conceived and it can well describe the transmission properties of the hole array in thick plates within a range of incidence angle. (c) 2008 American Institute of Physics