resolved variable retardations need to be introduced to the light beam. The orientation of the
fast axes of the retarders must be linearly independent on the Poincaré sphere if a fixed
starting polarization state is used, and one of the retardations requires a range of 2π. We
also present an experimental system capable of implementing this concept using two
passes on spatial light modulators (SLMs). A third SLM pass can be added to control the …