Brief review of acoustical (sonic) artificial lenses

The brief review of a modern state of art of acoustical artificial lens are observed. It has been shown that the subwavelength resolution in acoustical lens today may be achieved by metamaterial or artificial lens. It was mentioned that it is possible to obtain an acoustical analogue of photonic jet - acoustojet - to focus acoustical and sonic waves in subwavelength area by penetrable 3D mesoscale particle.