Effective spectral optical functions of lamellar nanogratings Martin Foldyna, Kamil Postava, Razvigor Ossikovski, Antonello De Martino and Enric Garcia-Caurel J. Eur. Opt. Soc.-Rapid Publ., 1 (2006) 06015 Published online: 18 September 2006 DOI: 10.2971/jeos.2006.06015