A problem of reflected light

atomqwerty

1. The problem statement, all variables and given/known data

If light with ellyptical polarisation moves from a medium of a given refractive index n1 into a second medium with refractive index n2 (let be I the initial energy of the beam and θ the angle), calculate the polarisation state and the reflected intensity.

2. Relevant equations

I found relevant the Fresnel equations for this one

3. The attempt at a solution

My question is: if the Jones vector of the light is given by [comma separates rows]: (A , B exp(-iφ)), where i is the imagniary unit and φ the relative phases between x and y (s and p), is the reflected light given by (rA , r'[B exp(-iφ)]) where r and r' are the parallel and perpendicular reflection coefficientes respectively? How can I the determine the phase lag φ introduced?

Thanks!!