Flexibly Steering of Self-Collimation Beam in Two-Dimensional Sonic Crystals

Almost no diffraction broadening of self-collimation beams and their easy crossing with low crosstalk offer new opportunities for acoustic wave manipulation. Here, we flexibly steer the self-collimation beam based on the total internal reflection of an airborne square lattice sonic crystal. The properly designed crystal/air interface may serve well as a total internal reflection mirror of the self-collimation beam, with which we are able to achieve the highly controllable beam reversal, snaking and crossing. Our scheme can be extended to more interesting beam steering, and have potential applications in constructing high-density integrated acoustic circuits.