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Homework Help: HOW TO FIT - Sellmeier curve?

  1. Oct 28, 2007 #1
    I have five, very precise, experimental values of refractive index for five different wavelengths and would like to draw the Sellmeier fit of the form:

    n^2=A1+A2/(1-A3/lambda^2) + A4/(1-A5/lambda^2)

    So, to find A1, A2, A3, A4 and A5 parameters I need to solve the system of five equations. Those equations are nonhomogenous. I would like to use Matlab program to solve that, but I don’t know which function and which form to use…Anybody already solved this? Thanks!
  2. jcsd
  3. Oct 28, 2007 #2


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    To solve numerically, you could use the multivariable Newton Raphson technique.

    In Matlab, I'd guess you need the SOLVE command. Here's the online help documentation
    Last edited: Oct 28, 2007
  4. Oct 29, 2007 #3

    Thanks! Sellmeier is now solved:cool:
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