One data point for one film can be characterized by the four numbers qz, energy, intensity and type of polarization.
Dependent on the type of measurement different modifications could be helpful to analyze the data. The program is capable to do this modifications automatically.
The two main effects in reflectometry are the reflection and transmission at the interfaces (fresnel equations) and interference. If you neglect the roughness at the interface the fresnel part is proportional to 1 / qz^4. Therefore by multiplying the result by qz^4 one can emerge the interference part of the result.
(TODO: Fit linear if this option is enabled)
The Fresnel formulas between sigma and pi light differ by a factor /cos(2*theta)^2. If you want to compare the dichroism between sigma- and pi-light you can enable this option.
Fourier transforms the spectra to determine the layer thicknesses.