Rigorous Diffraction Interface Theory
  We present a new formalism for understanding the optical properties of metasurfaces, optically thin composite diffractive devices. The proposed technique, Rigorous Diffraction Interface Theory (R-DIT), provides an analytical framework for understanding the transition between optically thin and optically thick structures. For metasurfaces, R-DIT avoids the calculation of optical propagation through thin layer and provides a direct link between the composition and geometry of a metasurface and its transmission, reflection, and diffraction properties. 
Christopher M. Roberts and Viktor A Podolskiy
physics.optics