This work introduces and investigates a metallic acoustic holographic lens to create an arbitrary acoustic pressure pattern in a target plane, using sound reflection phenomenon. The lens performs as a spatial sound modulator by introducing a relative phase shift to the reflected wavefront. The phase-shifting lens is designed using an iterative angular spectrum algorithm, and 3D-printed from powdered aluminum through direct metal laser melting. Then its capabilities to construct diffraction-limited complex pressure patterns and create multifocal areas are tested under water, numerically and experimentally. The proposed holographic lens design can drive immense improvements in applications involving medical ultrasound, ultrasonic energy transfer, and particle manipulation.
Through-wall acoustic energy transfer (TWAET) using piezoelectric devices is a technology proposed for wirelessly charging sensors in enclosed shells or vessels typically found in automobiles, space stations, and nuclear reactors. This mode of energy transfer has received significant attention in recent years as they outperform the traditional electromagnetic based through-wall wireless power transfer techniques which suffer due to Faraday shielding. Although useful, the existing framework is not suited to charge an enclosed sensor network. To address this shortcoming, we present, for the first time, acoustic holograms for selective TWAET and the details of the design, experiments, and potential applications.
Ultrasound acoustic energy transfer (UAET) is a transformative contactless energy transfer (CET) technology that outperforms conventional electromagnetic based CET techniques to recharge and communicate with low-power implanted medical devices which eliminates the need for invasive surgery. The limited modeling and proof-of-concept experiments on AET were performed in the linear range with several assumptions by neglecting the nonlinear wave propagation and the electroelastic nonlinearities of transmitter and receiver that become significant at higher source strengths and influence energy transfer characteristics. We present a series of experiments and experimentally-validated multiphysics models that we considered to address the knowledge gaps in UAET.
Ultrasound acoustic energy transfer systems are receiving growing attention in the area of contactless energy transfer for its advantages over other approaches, such as inductive coupling method. To date, most research on this approach has been on modeling and proof-of-concept experiments in the linear regime where nonlinear effects associated with high excitation levels are not significant. We present an acoustic-electroelastic model of a piezoelectric receiver in water by considering its nonlinear constitutive relations. The theory is based on ideal spherical sound wave propagation in conjunction with the electroelastic distributed-parameter governing equations for the receiver’s vibration and the electrical circuit.