Effective medium approximation of anisotropic lamellar nanogratings based on Fourier factorization
De Martino, Antonello
- Publisher: Optical Society of America
anisotropic optical materials | periodic nanostructures | gratings | ellipsometry and polarimetry | diffraction gratings | materials and process characterization
Anisotropic lamellar sub-wavelength gratings (nanogratings)
are described by Effective Medium Approximation (EMA). Analytical
formulas for effective medium optical parameters of nanogratings from
arbitrary anisotropic materials are derived using approximation of zeroorder
diffraction mode. The method is based on Rigorous Coupled Wave
Analysis (RCWA) combined with proper Fourier factorization method.
Good agreement between EMA and the rigorous model is observed, where
slight differences are explained by the influence of evanescent higher
Fourier harmonics in the nanograting.