Fourier Modal Method and Its Applications in Computational Nanophotonics

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A Perfect Matched Layer for Fourier Modal Method

In this chapter, a perfect matched layer (PML) for Fourier modal method (FMM) is described. Although actual space is made up of half-infinite spaces with reflectionless outgoing waves, every simulation method, such as FMM, finite-difference time-domain (FDTD), and finite-element method (FEM), works, in practice, in a finite-sized computation space. Therefore it is inevitable that this computational region would be surrounded by boundaries that perform as if there were half-infinite spaces outside those boundaries. A PML is an artificial layer that permits the accurate calculation of the distribution of an electromagnetic field inside the computational region by satisfying outgoing wave conditions. ...