The Fast Solver to Calculate the Scattered Fields from Nano-Periodic Structures Based on Integral Equations

Nano-periodic metallic grating structures are novel components that have several extraordinary optical transmission phenomena, such as surface plasmon polariton (SPP). In this work, we proposed a new efficient method based on the modified Neumann-to-Dirichlet (NtD) map to calculate the scattered fields from the nano-periodic metallic grating structures. In each sud-domain from the periodic metallic gratings, we construct the modified NtD map operators by boudary integral equations. The new operators avoid the numerical instability of the condition numbers from the challenging metallic materials with complex refractive index. Numerical result demonstrates that the new method achieves high accuracy for metallic diffraction gratings and indicates the phenomenon of surface plasmon polariton.