Acoustic extraordinary refraction in layered sonic crystals with periodic slits

In this paper, we present a study of acoustic wave propagation in layered sonic crystals (SCs) with periodic slits, and demonstrate the extraordinary acoustic refractions induced by acoustic backward and forward wave effects in SCs. By tuning the parameters of geometry structures and incident angles of acoustic waves, the positive, negative and zero acoustic refractions are demonstrated respectively. Taking advantage of the exotic acoustic refraction, we present the splitting of acoustic beams through the layered SCs, which is a new method to achieve acoustic beam splitting.