Visualization of the rotation of the plane of linearly polarized light for a superposition of phase-shifted circular polarizations.
Linearly polarized light can be written as a superposition of left-handed and right-handed polarized light. An optically active substance behaves as a wave plate (exhibits birefringence) for these two circularly polarized components. Thus, a mutual phase shift of these two components occurs. In the resulting superposition, the plane of linearly polarized light rotates by an angle $\Delta \varphi/2$ if, after passing through the optically active substance, the phases of the left- and right-handed components shifted by $\Delta \varphi$.
Source code containing interactive graph: nb