Elastic complementary meta-layer for ultrasound penetration through solid/liquid/gas barriers

초록

Efficient ultrasound transmission is crucial in vast areas including noninvasive surgery, structural health monitoring, and underwater detection. However, extreme impedance contrast of interfering media spanning from solid to liquid and even gas seriously harms ultrasound transmission efficiency. Here, we propose a complementary meta-layer (CML) to "virtually cancel out " not only dissimilar solid but also liquid and gas barriers for highly enhanced transmission through the barriers in wave propagation perspective. Our proposition is apparently the first elastic CML and it is uniquely designed in a monolayer. The meta-atom forming a single meta-layer consists of spatially separated dipolar and monopolar resonators with completely independent tunability of effective negative properties. The proposed CML is capable of enhancing the ultrasound transmission by 593%, 1426%, and 3280% respectively for the polymer, water, and air barriers by numerical simulations. The proposed methodology to "cancel out " diverse barriers of highly dissimilar impedances can be groundbreaking in various ultrasound applications.

키워드