2D materials offer a large variety of optical properties, from transparency
to plasmonic excitation. They can be structured and combined to form
heterostructures that expand the realm of possibility to manipulate light
interactions at the nanoscale. Appropriate and numerically efficient models
accounting for the high intrinsic anisotropy of 2D materials and
heterostructures are needed. In this article, we retrieve the relevant
intrinsic parameters that describe the optical response of a homogeneous 2D
material from a microscopic approach. Well-known effective models for vertical
heterostructure (stacking of different layers) are retrieved. We found that the
effective optical response model of horizontal heterostructures (alternating
nano-ribbons) depends of the thickness. In the thin layer model, well adapted
for 2D materials, a counter-intuitive in-plane isotropic behavior is predicted.
We confront the effective model formulation with exact reference calculations
such as ab-initio calculations for graphene, hexagonal boron nitride (hBN), as
well as corrugated graphene with larger thickness but also with classical
electrodynamics calculations that exactly account for the lateral
structuration