Figure 3
Absorptance against the truncated order N. The operating frequency and incident angle are 2.5 THz and \(\theta =60{^{\circ}}\), respectively. The dotted curve in green colour is obtained by conventional FMM; the dashed curve in black colour is calculated by this approach (FMM incorporating LBFs); the dashed curve in red, blue and magenta colours individually correspond to \(h=w_g/20000\), \(h=w_g/2000\), and \(h=w_g/200\), respectively, for the FMM with ABC20.
