Monochromatic light with circular polarization falls normally on a crystalline plate cut parallel to the optical axis. Behind the plate there is a Nicol prism whose principal direction forms an angle \(\varphi\) with the optical axis of the plate. Demonstrate that the intensity of light transmitted through that system is equal to \[ I=I_{0}(1+\sin 2 \varphi \cdot \sin \delta) \] where \(\delta\) is the phase difference between the ordinary and extraordinary rays which is introduced by the plate.