Ultrasensitive Ultrasound Coming Thanks to New Plasmonic Metamaterial

Ultrasound transducers that generate and sense acoustic waves rely on piezoelectric materials to convert mechanical stress into an electric potential. Though this technology has been pushed over the decades to generate ever better imaging, it suffers from fundamental limitations in bandwidth…

Ultrasound transducers that generate and sense acoustic waves rely on piezoelectric materials to convert mechanical stress into an electric potential. Though this technology has been pushed over the decades to generate ever better imaging, it suffers from fundamental limitations in bandwidth and sensitivity. Searching for a new solution to next generation ultrasound imaging, researchers from Texas A&M, King’s College London, The Queen’s University of Belfast and the University of Massachusetts Lowell have created a new technology that uses plasmonic metamaterials to convert sounds waves directly into light beams.

The team claims that their technique does not suffer from the bandwidth and sensitivity limitations of piezoelectric materials and should lead to significantly improved ultrasound imaging in medicine and in other applications.
More details from the news announcement:

The material, [Prof. Vladislav Yakovlev of Texas A&M] notes, consists of golden nanorods embedded in a polymer known as polypyrrole. An optical signal is sent into this material where it interacts with and is altered by incoming ultrasound waves before passing through the material. A detection device would then read the altered optical signal, analyzing the changes in its optical properties to process a higher resolution image, Yakovlev explains.

“We developed a material that would enable optical signal processing of ultrasound,” Yakovlev says. “Nothing like this material exists in nature so we engineered a material that would provide the properties we needed. It has greater sensitivity and broader bandwidth. We can go from 0-150 MHz without sacrificing the sensitivity. Current technology typically experiences a substantial decline in sensitivity around 50 MHz.
Study in Advanced Materials: Ultrasensitive Non-Resonant Detection of Ultrasound with Plasmonic Metamaterials
Press release: Improved Ultrasound Imaging Coming Soon