Example：10.1021/acsami.1c06204 or Chem. Rev., 2007, 107, 2411-2502
High-frequency leaky whispering-gallery modes in embedded elastic spheres Physical Review B (IF4.036), Pub Date : 2021-12-01, DOI: 10.1103/physrevb.104.214101 Fabien Treyssède, Matthieu Gallezot
The goal of this paper is to investigate the characteristics of high-frequency whispering-gallery modes in embedded elastic spheres, that is, surrounded by an infinite elastic matrix. Due to several modeling difficulties, the high-frequency regime of embedded spheres has remained unexplored in elasticity. Our approach consists of formulating a specific finite-element method in spherical coordinates. The basic idea is to discretize only the radial coordinate while describing analytically the angular distribution of elastodynamic fields. Then, we also introduce a radial perfectly matched layer to cope with the unbounded nature of the external medium. Our approach yields a linear matrix eigensystem, simple and costless to solve. In order to identify general trends, both stiff and soft configurations are considered, corresponding to a sphere stiffer and softer than the external medium, respectively. Including material loss, our results highlight the behavior of leaky elastic whispering-gallery modes in the high-frequency regime. This work is motivated by the well-known behavior of whispering-gallery modes in optical resonators, reaching high factors as the frequency increases. Identifying high--factor whispering-gallery modes in elastic spheres could find promising applications for sensing the mechanical properties of external media.