Has Labview been used to fit reflectance spectra in film metrology

[M_T]

I was wondering if the Labview signal processing VIs have been used to fit reflectance spectra for transparent thin films on reflective surfaces?  The interference pattern is related to film thickness and index of refraction.  I am wondering which Vis would be the best starting point for curve fitting a bragg interference formula? 

[F._Schubert]

Most propably you will need to understand the nonlinear curve fitting vi(s?). Then any formula you want might be applied to the data.

If you can provide the formula (I mean post it here), maybe someone knows if there is an appropriate vi ready made (or someone might share one as a starting point). But I guess you will need to do it on your own (but the specific problems will get adressed on the forum, altenbach is a big fitting-guru). 

Felix 

[M_T]

The destructive interference equation would be 2p(2nnd/c - 1/2) = (2M + 1)p, where n = frequency, n = index of refraction, d = film thickness, c = speed of light, and M = minimum number.  An interest is to add the index of refraction as a function of wavelength, n(l),  so the destructive interference equation would change to 2p(2nn(l)d/c - 1/2) = (2M + 1)p.  The unknown property would be the film thickness.

[Ben]

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M_T wrote:

I was wondering if the Labview signal processing VIs have been used to fit reflectance spectra for transparent thin films on reflective surfaces?  ...

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Yes.

When you look in the rear-view mirror of a Mustang, you are looking through glass that was evaluated by a LV app. That app funded the start-up of the company I work for now.

Ben

[M_T]

Ben,

Can you elaborate?  There are so many Vis in Labview 8.6 related to spectral processing.  I was wondering which Vi would be good at modeling the Bragg interference spectrum.   I found a vi that can pull out the Max/min values, but I was also interested in obtaining a fitting error.  Just wondering if you had any thoughts.

Again, thanks for the earlier message.

Larry