Depolarization in the Mueller calculus

Depolarization is the generation of partially polarized light or unpolarized light from a completely polarized incident beam. For example when polarized light scatters from rough surfaces, the degree of polarization is usually reduced from one. Depolarization figures of merit are discussed and difficulties with the depolarization index are highlighted. Interesting depolarization patterns are presented for a liquid crystal in reflection are measured with a commercial polarimeter. Depolarization data from rough metal surfaces and paint is also discussed.