Extinction of a doped graphene nanoribbon array

This widget calculates the normal-incidence extinction for a ribbon array placed in an asymmetric environment, as shown in the graph below. The dielectric function of media 1, 2, and c (coating) can be specified from the given lists of tabulated optical data, or they can be assigned different Lorentz-Drude functions ε(ω)=ε_b+ω_p²/[ω_g²-ω(ω+iη)] (for example, this feature can also be used to assign a constant value or to model a dielectric with an excitonic mode). The coating of thickness t_c can be arbitrarily small, and it is incorporated in a rigorous way through an extended version of the theory discussed in F. J. García de Abajo, ACS Photon. 1, 135 (2014). However, the spacing of thickness t₂ is assumed to be sufficiently thick as to ignore the scattering at the 2-3 interface of evanescent diffraction orders produced by the array. In the dipole approximation (see below), each ribbon is represented as a line dipole. In the plasmon-wave-function (PWF) approach, each plasmon is represented by its induced density, and the interaction between plasmons in different ribbons is described rigorously, so this method works even at very small separations. This widget incorporates the two lowest-order dipole-active plasmons of each ribbon.