Domain Decomposition Scheme in Newmark-Beta-FDTD for Dispersive Grating Calculation

Abstract

In this work, an efficient domain decomposition scheme is introduced into the unconditionally stable finite-difference time-domain (FDTD) method based on the Newmark-Beta algorithm. The entire computational domain is decomposed into several subdomains, and thus the large sparse matrix equation produced by the implicit FDTD method can be divided into some independent small ones, resulting in a fast speed lower-upper decomposition and backward substitution. The domain decomposition scheme with different subdomain schemes and different subdomain numbers is studied. With a generalized auxiliary differential equation (ADE) technique, the extraordinary optical transmission through a periodic metallic grating with bumps and cuts is investigated with the domain decomposition Newmark-Beta-FDTD. Compared with the traditional ADE-FDTD method and the ADENewmark- Beta-FDTD method, the results from the proposed method show its accuracy and efficiency.