Experimental demonstration of underwater ultrasound cloaking based on metagrating

We present the theoretical design, numerical simulation, and experimental demonstration of a single-parameter-based underwater ultrasound cloaking of arbitrary objects based on metagrating. The carpet metagrating is implemented with periodic grooves, which circumvents the tedious calculations and extreme material responses of the conventional cloaking based on acoustic transformation theory, providing a simple design methodology and enabling easy fabrication in real-life scenarios. Particularly, we expand the working frequency range of this ultrasound cloaking to 100–900 kHz, which is commonly used in biomedical ultrasound and industrial testing. Our design with the advantages of extreme simplicity, robust concealment of sizeable objects, and potential broadband functionality will improve the applicability of ultrasound carpet cloaking for more realistic situations where the camouflage of the arbitrary target is needed.