Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

    User Avatar
    Science Advisor
    Education Advisor
    2016 Award

    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.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook