Consider a rectangular block of material exhibiting this effect (length L along the z-axis). It has refractive indices nR and nL for right- and left- circularly polarized waves, respectively, propagating along the z-axis. Consider a wave of wavelength which is propagating along the z-axis and is linearly polarized as it enters the block (assume the lateral extent of the block completely contains the wave).

1. Show that the waves polarization remains linear but rotates as it propagates through the block.
2. Derive an expression for the total rotation angle of the linear polarization experienced by the wave as it exits the block (ignore multi-paths formed from reflection at interfaces).