Dual-band topological rainbow trapping and frequency separation in two-dimensional elastic phononic crystals

Rainbow trapping and the frequency separation of elastic waves in topological phononic metamaterials hold significant promise for information processing. However, a shared acoustic channel for frequency separation complicates acoustics signal processing. In this paper, we constructed a unit cell by etching curved slots into an aluminum plate and analyzed its topological properties using two-dimensional polarization techniques. By adjusting the structural parameters and creating three gradient structures, we achieved rainbow trapping and frequency separation across a dual frequency band. This allows waves of different frequencies to be split and directed to various locations, while other frequencies can be output from different ports. This study offers an effective approach for separating and capturing acoustic signals, with potential applications in engineering and technology.