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Diffraction from Sub-Wavelength Features

  1. Sep 4, 2011 #1
    I was wondering what occurs when a diffraction grating is produced with features smaller than a wavelength of visible light. If the pits in a CD were made to be only a few tens of nanometers wide, what would we see?
  2. jcsd
  3. Sep 5, 2011 #2
    The minimum intensity occurs at angles given from the following law:[itex]d\sin\theta_{min}=\lambda\approx \theta_{min}=\frac{\lambda}{d}[/itex]
    So, if [tex]d <<\lambda[/tex], then [tex]\theta_{min}[/tex] becomes great: you can't see any minimum of diffraction.
    Last edited: Sep 5, 2011
  4. Sep 5, 2011 #3

    Andy Resnick

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    It entirely depends on the details- pit spacing, etc. Subwavelength apertures produce evanesecent field modes. People have been trying to exploit that property for super-resolution imaging.
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