Characterization of retardance of nondepolarizing and depolarizing media

A criterion for the characterization of the retardance effects produced by depolarizing and nondepolarizing linear media on interacting light is established based on Mueller matrices algebra. A consistent general description of retardance properties is performed by means of a serial decomposition of the Mueller matrix into three components, namely an element that encompasses the enpolarizing and depolarizing properties sandwiched by two elliptical retarders containing complete and decoupled information on retardance. The inherent ambiguity derived from the coincident formal structure of rotation matrices and circular retarders is removed though the introduction of the entrance and exit intrinsic reference frames, leading to the concepts of the intrinsic entrance and exit linear retarders, which are defined from the Mueller matrix itself and that are independent of the laboratory reference frames used to represent the incident and emerging polarized light beams, respectively.