High-resolution acoustic field mapping of gigahertz phononic crystals with atomic force microscopy

Manipulating mechanical waves at gigahertz frequencies can lead to next-generation communication technologies, but designing wave-controlling devices requires high-resolution and fast-scanning mapping of acoustic fields. The authors introduce the use of acoustic atomic force microscopy to characterize phononic crystals at gigahertz frequency, showing mechanical vibration mapping with tens-of-nanometer resolution and symmetry-dependent scattering. This study sets the baseline for advanced operations like hyperspectral filtering, beam steering, or spatial-division multiplexing, and will have an impact on the development of acoustic-based microwave technologies.