Multiplexed reflection and transmission gratings, and methods of their manufacture, are provided that improve uniformity with laser light, that is, reduced banding and other illumination artifacts occurring in waveguides. The mechanism for this can be the multiple reflections between the waveguide reflecting surfaces and the reflection hologram, which promote illumination averaging as beam propagation processes within a waveguide. In some gratings, a beam splitter layer overlapping the multiplexed gratings can be provided for the purposes of reducing banding in a laser-illuminated waveguide. The beam splitter can be provided by one or more dielectric layers. The beamsplitter can have sensitivity to one polarization. The beamsplitter can be sensitive to S-polarization. The beam splitter can be an anti-reflection coating optimized for normal incidence that becomes reflective at high TIR angles when immersed in glass or plastic.