Observation of a complete band gap for liquid surface waves propagating over a periodically drilled bottom

We study both theoretically and experimentally the propagation of liquid surface waves over a periodically drilled bottom. A slab of a plate drilled with a triangular array of holes is placed in the middle of a liquid vessel. With the presence of point source waves generated on the one side of the plate, we can obtain propagative information of liquid surface waves through the observations of the outgoing waves on the other side of the plate. Our experiment confirms our previous theoretical predictions of the existence of complete band gaps for liquid surface waves propagating over a periodically drilled bottom.