Comparison of Frequency Transformation in Time-Varying Dielectric Plane Waveguide and Circular Resonator

This paper presents the analytic results of comparison of mode transformation in 2D time-varying photonic structures on examples of plane waveguide and circular whispering gallery mode (WGM) resonator. The situation is that a natural mode propagates inside the structure at the moment when the refractive index changes abruptly in time inside it. The basic interest is to gain insight into details of the mode evolution during the transient period. We reveal the common features that underlie these phenomena in both structures. Numerical examples are provided