Anyone knows where i could find some good reading materials on the effects of sub-wavelength ordered structures on light? I know how it works when the spatial frequency of the structure is large enough - then i can just use fresnel or fraunhofer diffraction (if i'm far enough). Sub wavelength structures just produce evanescent waves according to these theories.. I shouldn't be able to see their effect if I'm watching them from a distance (which is in a greater order of magnitude then the wavelength - so everything my eye can focus on is far enough)... So I don't understand how there are optical effects which stem from these structures... I've heard of a "zero order grating" which seems to selectively reflect wavelengths at different incident angles (but not diffract them - the angle of reflection is the angle of incidence - the 0'th order..) when trying to find some material on it, i came across the terms "effective medium theory" and "coupled waves"... but i couldn't find anything which would connect it all and explain these "zero order gratings".