Subwavelength gratings

  • Thread starter fargoth
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  • #1
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Main Question or Discussion Point

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".
 

Answers and Replies

  • #2
mda
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Subwavelength gratings are still a fairly active field of research so books aren't readily available, but you might try searching photonics.com for popular articles.

The most obvious far-field effect of subwavelength gratings is strong polarization... for example the wire grid polarizer is mentioned as the first example of a 'polarizer' on wiki.
The polarizing effect is a result of the highly directional nature of the wires.

Beyond that there are interesting resonant effects, especially if you combine with metal layers or other gratings. Such resonances typically involve plasmons, which loosely are evanescent waves associated with metal surfaces.
 
  • #3
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thank you very much for your reply.

so i guess i'll have to order some articles and try my best to understand it from there... and maybe they even got some good references there too...
 
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