Complex refractive index mesurement from reflectivity data

[Gobil]

hi All,

Just wondering how you get the complex refractive index of a material from relectivity measurements at a single angle. I understand you must infer some of the data, using the Kramers Kronig relations, is this right?

Is there a direct way of calculating it? I see from an article on elipsometry that is you have the ratio of the reflction of plane and parallel polarised light

from wiki

Ps/Pp = tan(Phi)exp(ixdelta)

where delta is the phase shift, and the amplitued is tan(Phi), but here you still have one unkown. Any ideas on doing this without the kramers kronig relation?

cheers
Gobil

 

[Ravian]

ellipsometry measures n, k and e1, e2 directly. however if you have reflectivity data from photospectrometer then you may use R=(n-1)^2+K^2/(n+1)^2+k^2, you will have to account for multiple reflections