Exploiting the Poincaré–Bloch symmetry to design high-fidelity broadband composite linear retarders

States can be mapped between the Poincaré space (representing photon polarizations) and the Bloch space (representing states of a quantum spin-1÷2 particle). Using this mapping and analogous mappings for unitary operators, techniques and formalisms developed in one space can be applied in the other. As an example, error-correction strategies originally developed in the context of pulsed nuclear magnetic resonance experiments are applied to linear optics to propose the design of a new class of composite high-fidelity broadband linear retarder. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft