“…This is in particular advantageous if the frequency dependence of the refractive index has to be included. For the frequency domain several approaches can be applied to quasi-two-dimensional geometries, such as the finite-difference frequency-domain (FDFD) method (Shainline et al, 2009), wave-matching method (Hentschel and Richter, 2002;Nöckel and Stone, 1995), internal scattering quantization approach (Tureci et al, 2005), volume element methods (Martin et al, 1999), boundary element methods (Wiersig, 2003a;Zou et al, 2011) and related methods based on boundary integral equations (Boriskina et al, 2004). The FDFD and the volume element methods are restricted to small structures because of the limited computational power that is available today.…”