How does a Fresnel rhomb work (half and quarter wave plate)?
I am aware of birefringence, which creates a phase shift of $\Delta\phi=\dfrac{2\pi\Delta nL}{\lambda_0}$. But this doesn't explain how a plane polarised light shifts it's polarization angle after a half-waveplate or how a linearly polarised light becomes elliptical after a quarter-waveplate.
For the half one let's assume that wikipedia has an answer http://en.wikipedia.org/wiki/Waveplate but why this electric field
$E(\hat{f}+i\hat{s})e^{i(kz-\omega t})$ describes an elliptical polarised light?
What I need is a mathematical description of how the retarders work...
