Homogenization of membrane and pillar photonic crystals
  We study wave propagation and diffraction in a bidimensional photonic crystal with finite height, in case where the wavelength is large with respect to the period of the structure. The device is made of materials with anisotropic permittivity and permeability tensors. We derive rigorously the homogenized system, using the concept of two-scale convergence. The effective permittivity and permeability tensors turn out to be that of a two-dimensional photonic crystal with infinite height. 
D. Felbacq, G. Bouchitt\'e, A. Moreau