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Superposition principle in arbitrary medium

  1. Oct 16, 2010 #1
    Does the superposition principle for wave equations (say electromagnetic) hold also for non homogeneous and anisotropic media? I.e. can one always represent a wave traveling in an arbitrary direction as a sum of waves propagating along the principal axes of, e.g. dielectric tensor [tex]\epsilon_{ik}[/tex]?

    Thanks
     
  2. jcsd
  3. Oct 16, 2010 #2

    Andy Resnick

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    The superposition principle is violated in nonlinear materials- some basic examples are the Stark and Kerr effects.

    Another effect is the spectral changes that occur as partially coherent light propagates in free space (sometimes called the Wolf effect)- but this may not count as a violation of superposition.

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2915902/

    http://www.sciencedirect.com/scienc...4d4d39ef9500de32bd2e9337d46bda5b&searchtype=a
    http://www.opticsinfobase.org/abstract.cfm?uri=josaa-7-9-1591
     
  4. Oct 16, 2010 #3
    So, as long as the medium is linear, superposition holds as a rule?
     
  5. Oct 16, 2010 #4

    Andy Resnick

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    Yes- at least, I am unaware of any exceptions.
     
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