image: Shima Shahab and Ahmed Sallam with an acoustic hologram plate view more
Credit: Alex Parrish for Virginia Tech
Shima Shahab, an assistant professor of mechanical engineering and director of Multiphysics Intelligent and Dynamical Systems Laboratory, was awarded an Early-Concept Grant for Exploratory Research (EAGER) from the National Science Foundation to fund research in the largely uncharted territory of acoustic holograms.
Shahab is the principal investigator on a study that will investigate the way sound waves are reshaped as they encounter an engineered lens and the reshaping of a wave within body tissues.
Acoustic holograms use lens plates to pattern acoustic energy in similar ways to the workings of a shower head with water, Shahab explained. The lens in an acoustic hologram moves sound waves through an engineered surface of varying thicknesses and shapes, comparable to a shower head as it distributes streams of water through holes. The sound is aimed at the lens in much the same way as water is pushed through the shower head, and the pattern of the lens surface causes the sound to redistribute based on its design.
Passing through the lens may cause sound waves to change direction, overlap one another, or change intensity. These sound waves create vibrations, and those vibrations can affect change on physical surfaces.
Manipulating sound waves in this way has many applications, from artistic to medicinal. Shahab and her doctoral student, Ahmed Sallam, have collaborated previously with Eli Vlaisavljevich in the Department of Biomedical Engineering and Mechanics to test the capability of acoustic holograms for non-invasive treatment of neurological disorders.
To fully understand the value of sound waves in this treatment, it is important to know how high-intensity sound waves are affected in an acoustic hologram and how they might be changed as they pass through. To achieve treatment precision, Shahab is studying the altered sounds to determine the pattern being created after they encounter the lens.
Another part of the study will explore sound reshaping within tissues. Just as a sound wave is distorted when it passes through a holographic lens, body tissues also create changes to its properties. To shape an effective medical treatment using this method, both impacts must be more fully understood and harmonized.
Shahab expanded on the idea. “We envision that the acoustic holographic lenses have the potential to extend the realm of critical applications that employ manipulation of acoustic waves and amplify contactless energy transfer capabilities.”
According to the NSF, EAGER grants are used to support exploratory work in its early stages on untested but potentially transformative research ideas or approaches. This work may be considered especially "high risk, high payoff" in the sense that it involves radically different approaches, applies new expertise, or engages novel disciplinary or interdisciplinary perspectives.