A device for illuminating a spatial light modulator includes a light source and an optical element. The light source is configured to provide illumination light. The optical element has a first surface, a second surface that is distinct from and non-parallel to the first surface, and a third surface that is distinct from and non-parallel to the first surface and the second surface. The optical element is configured to receive the illumination light at the first surface, propagate the illumination light via total internal reflection, and output the illumination light from the third surface. Also disclosed is a method performed by the device.