i tried to turn off and on the Show Material Data as per your advice, but still it didn't appear.
And i tried using the getindex via script editor. this is what i get.
i think it's not a good fit and how do i make it properly fit?
also, do you think that my initial wavelength, refractive index data is not sufficient as i have only up to 16 rows? perhaps i should add in more, say up to 50 or more?
thanks for your help.