Zero Thickness Sheet Model of Dispersive & Nonlinear Metasurfaces

A systematic method to represent and analyze a practical nonlinear metasurface exhibiting temporal dispersion, using an equivalent zero thickness sheet model is proposed. The method is based on Generalized Sheet Transition Conditions (GSTCs), where the metasurface is described in terms of linear and nonlinear surface polarization densities modeled using a nonlinear Lorentz oscillator. The equivalent Lorentz parameters are extracted from unit cell simulations, and using numerical examples, it is shown that they can successfully replicate the dispersion and intensity-dependent nonlinear response of the finite-thickness metasurface.