Fitting a Sellmeier equation to five refractive index measurements in Matlab

[hrky]

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!

 

[siddharth]

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

 

[hrky]

thx!

Thanks! Sellmeier is now solved