An optical system for directing image illumination injected at a coupling-in region to an eye-motion box for viewing by an eye of a user, including a light-guide optical element (LOE) formed from transparent material that includes: a first region containing a first set of planar, mutually-parallel, partially-reflecting surfaces having a first orientation; a second region containing a second set of planar, mutually-parallel, partially-reflecting surfaces having a second orientation non-parallel to the first orientation; a set of mutually-parallel major external surfaces extending across the first and second regions, and an optical retarder deployed between the first region and the second region so as to rotate a polarization of light deflected by the first set of partially-reflecting surfaces prior to reaching the second set of partially-reflecting surfaces.