A polarization-mixing light guide includes a plate light guide and a polarization retarder within the plate light guide. The light guide is to guide a beam of light at a non-zero propagation angle. The light beam includes a first polarization component and a second polarization component. The polarization retarder is to redistribute the first and second polarization components of the guided light beam into predetermined combinations of the polarization components. The light guide is to preferentially scatter out a portion of the guided light beam having the first polarization component. A three-dimensional (3-D) electronic display includes an array of multibeam diffraction gratings at a surface of the plate light guide to preferentially couple out the first polarization component of the guided light beam as a plurality of light beams having different principal angular directions.