Infrastructure for Manufacturing and Testing of Megahertz Ultrasound Metamaterials
* Presenting author
Abstract:
Recent developments in acoustic metamaterials demonstrate promising properties for the manipulation of sound waves. Precise control of sound is of high interest in many applications (e.g. high intensity focused ultrasound and acoustic levitation). However, effective metamaterial structures for ultrasound in the megahertz range have microscopic dimensions and are difficult to manufacture with macroscopic methods generally utilized for acoustic metamaterial fabrication. Another challenge is the characterization of corresponding ultrasound fields at these frequencies in air verifying numerical simulations. These issues hamper the technology transfer of ultrasound metamaterials from fundamental to applied research areas and to industrial applications.To conquer these challenges, an innovative manufacturing approach to fabricate prototype samples consisting of structures with typical dimensions in the micrometer range is necessary. For high frequency sound field measurements, the use of special microphones based on refractive index changes or piezoelectric foils is required.We combine additive manufacturing of metamaterials based on two-photon-lithography with in-house capacitive ultrasound transducers and a test bench for the high frequency domain. This unique setup allows for the first time a consolidated fabrication and characterization of acoustic metamaterials for ultrasound in the megahertz range.