Session: Rising Stars of Mechanical Engineering Celebration & Showcase

Paper Number: 147874

147874 - Acoustic Angular Momentum Propagation in Complex Media and Applications for Medicine and Communications 

Angular momentum carrying acoustic waves, such as acoustic vortex beam, are a special type of sound waves that have a rotating pressure field or energy flux. Previous studies indicated that these waves could have many potential biomedical applications, including medical imaging with better resolution than traditional ultrasound imaging and targeted ultrasonic removal of kidney stones and blood clots with higher efficacy than classical focused ultrasound therapies. However, these studies focused on waves propagating underwater and ignored the anisotropy and heterogeneity of biomaterials such as muscle fibers. Recent theoretical studies have indicated that acoustic angular momenta will couple when propagating in anisotropic or heterogeneity materials, altering the propagation path of the wave, and potentially impeding their reliable use in the suggested biomedical applications. The research supported by this CAREER award seeks to understand the fundamental coupling mechanism between different acoustic angular momenta, especially when propagating in anisotropic biomaterials, through modeling and experimentation. This understanding will be applied to demonstrate imaging and blood clot thrombolysis capabilities through anisotropic media. The results from this research will advance knowledge in acoustics, dynamics, biomechanics, as well as biomedical engineering, and can potentially lead to novel medical diagnostics and therapies. Moreover, The PI’s recent proof-of-concept experiment and the following studies by the PI and other researchers have demonstrated the effectiveness of enhancing information capacity and communication speed with acoustic orbital angular momentum (OAM) multiplexing. The acoustic OAMs are spatial degrees of freedom that are orthogonal to existing standard temporal and frequency domain modulation schemes and can be combined with these schemes to ultimately enhance communication speed for underwater communications. However, the transmission, robustness, and compatibility with existing modulation schemes of acoustic OAM communication underwater are not well characterized. The characterization of these critical performance factors is crucial before the acoustic OAM multiplexing can be implemented into underwater networks for naval applications. The specific objective of this ONR YIP Award is to evaluate the multiplexed acoustic OAM signal underwater transmission capacity, decoding schemes, and the compatibility with existing temporal and frequency modulation based communications for enhancing high-speed information transmission performance; and for practical applications to assess the OAM’s robustness against array’s aperture minimization requirement, malfunctioning array elements,  and relative motion between the transmitter and receiver. Besides the study of the acoustic angular momentum propagation in complex anisotropic or inhomogeneous media, we also focus on the intriguing mechanics and dynamics induced by the angular momentum carrying acoustic waves including the vortex wave induced shear stress in soft matters and enhanced cavitation. This poster presentation will summarize our work on both the propagation physics in complex media and the applications in medical treatments and underwater communications of acoustic angular momentum carrying waves.

Presenting Author: Chengzhi Shi University of Michigan

Presenting Author Biography: Dr. Chengzhi Shi is an Associate Professor in the Department of Mechanical Engineering at the University of Michigan. Before joining the University of Michigan, he was an Assistant Professor in the GWW School of Mechanical Engineering at Georgia Tech. Dr. Shi earned his Ph.D. degree from the University of California, Berkeley in 2018 and his M.S. and B.S. degrees from Shanghai Jiao Tong University in 2013 and 2010. His research interests include physical acoustics, wave propagation, metamaterials, ultrasound imaging, and therapeutic ultrasound. He has published many highly cited papers in renowned journals including Science, PNAS, and Nature Communications. Dr. Shi has also won prestigious awards including the NSF CAREER and the ONR YIP awards.

Authors:

Chengzhi Shi University of Michigan