First, I will discuss a now-classic topic but with some new twists: Transformation acoustics (TA), focusing on the special case of isotropic TA for which the required properties can be realized by a wide variety of homogenized structures. First, the ability of conformal mappings to yield highly accurate focusing lenses is described. These act via reciprocity as monopole to highly one-way-wave radiators. Second, matching to the exterior fluid places constraints on the TA map that are explored.
