Resonant Stratified Cylindrical Structures with Time Discontinuity in Permittivity

In this paper we consider the transformation of whispering gallery modes (WGM) of circular dielectric resonators due to temporal changes in permittivity inside the concentric circular region. We explore how the transients evolve from the complex interaction of reflections occurring at the dielectric interfaces. A closed form solution is obtained for the electric field component by applying the Laplace transform directly to the wave equation and enforcing the corresponding initial and boundary conditions.