Thank you all for your help. I already have Born's book, but to be honest it's quite complicated.
I found in Feynman's lectures a "gentler to the mind" version.
Dear All,
I have read many posts on this forums about the interaction of photons with the atoms of transparent materials. The point that I was searching for in particular was "why is the speed of light in transparent material less than c".
The explanations given by many about the absorption...