Rayleigh Waves in Phononic Crystal Made of Multilayered Pillars: Confined Modes, Fano Resonances, and Acoustically Induced Transparency

Accurate control of Rayleigh waves (which feature phase-shifted longitudinal and transverse components) is essential to improving devices based on surface acoustic waves (SAWs). The authors propose an approach for efficient manipulation of Rayleigh waves, using multilayered phononic pillars to provide high-$Q$ cavity modes to interact with the SAWs. Interaction with these strongly confined modes can give rise to Fano-like resonances, as well as an acoustic analog of electromagnetically induced transparency (EIT). This approach could open the way to SAW-based solutions in high-performance sensing applications, optomechanics, and phonon circuitry.