Broadband acoustic collimation and focusing using reduced aberration acoustic Luneburg lens

An acoustic Luneburg lens is a symmetric gradient-index with refractive index decreasing radially from the center to outer surface. It can be used manipulate wave propagation allowing collimation and focusing capabilities. Previously studied lenses based on conventional concept work only at audible frequencies ranging up 15 kHz or single ultrasonic frequency of 40 kHz. In this paper, by tailoring focal length different radius, reduced-aberration (RAALL) proposed for broadband omnidirectional focusing. Based ray trajectories obtained ray-tracing technique, RAALL achieve better in comparison modified optical design. Following analysis, two models [two-dimensional (2D) three-dimensional (3D) devices] are designed fabricated using additive manufacturing technology. Collimation performance waves analytically, numerically, experimentally investigated both 2D 3D lenses, their characteristics demonstrated.