Design, Fabrication and Testing of Microacoustic Metagratings at Ultra-High Frequencies (en)

* Presenting author
Day / Time: 08.03.2023, 17:00-17:20
Room: Saal Y8
Typ: Vortrag (strukturierte Sitzung)
Abstract: The recently proposed bianisotropic acoustic metagratings offer promising opportunities for passive acoustic wavefront manipulation, which is of particular interest for flat acoustic lenses and ultra-high frequency ultrasound imaging. In this work we scale up the concept of acoustic metagratings to MHz frequencies for airborne ultrasound and thus to a microscopic size of metagrating geometry. This leads to strongly increasing thermoviscous effects, which cause a drop in efficiency and a frequency reduction of the transmission peak. We present several microacoustic metagrating designs optimized for refraction of a normally incident wave towards -35° at 2 MHz, with and without including the thermoviscous effects in the modeling approach. Furthermore, we fabricate and experimentally investigate the designs, demonstrating the feasibility of microacoustic metagratings for anomalous refraction at ultra-high frequencies.


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