Large-scale electromagnetic simulations enabled by the modified Born series with virtual absorbing boundaries

Numerical Maxwell equation solvers are significant for optical inspection, in which large-scale simulations serve as an essential part. Absorbing boundary conditions (ABC) is required to simulate open-domain systems. However, the existing ABCs require large memory to sufficiently suppress boundary reflection, which is prohibitive for largescale applications. This work proposes a virtual boundary condition to reduce the memory usage. The angular spectrum method is used to cover the polluted field in the boundary region, which eliminates the need to store the field in the boundary region. Combined with the Fourier transforms-based modified Born series, memory usage can be reduced to a level close to the theoretical limit. This proposed method offers a substantial boost for applications related to large-scale simulations and memory-constrained devices like GPU.