1. The problem statement, all variables and given/known data I have a laser focused into a lithium niobate crystal and an analyzer placed after the crystal. The analyzer and laser are cross polarized. I'm trying to derive the equation that relates the phase difference of the o-wave and e-wave after the analyzer. I know it is dependent on the thickness, d, of the crystal, the birefringent refractive indexes, n(e,o), and wavelength λ (here, 633nm). 2. Relevant equations So far I'm aware the waves are split into two, of intensity (Eo/2)cos(wt±ε), where ε is the phase difference and Eo is the amplitude. 3. The attempt at a solution I've tried combining the two, then doing the difference of two cosines, but this didn't get me far but I am sure this is the along the right lines... Suggestions or thoughts would be greatly appreciated!!!