Impact of Time Step Scaling in TDIE MOT-JVIE for Metasurface Analysis

Metasurfaces are engineered structures consisting of subwavelength scatterers capable of manipulating the amplitude, polarization, and phase of an impinging electromagnetic wave. Their design process involves numerically solving Maxwell's equations. Among these solvers, the finite-difference timedomain (FDTD) method is currently the defacto standard owing to its versatility in handling complex geometries and its relatively low use of computational resources. However, FDTD is constrained by the Courant-Friedrichs-Lewy (CFL) condition, which requires the time step to scale relative to the spatial size. The CFL condition is mainly a problem for detailed structures that are sub-wavelength, like in metamaterials. This challenge drives research toward overcoming CFL limits for faster, more accurate large-scale metasurface simulations [1].