A backlight includes a visible light transmissive body having a light guide portion and a light input portion. The visible light transmissive body primarily propagates light by TIR and includes a light input surface and a light output surface. The light guide portion has a light reflection surface and a light emission surface. The light input portion has opposing side surfaces that are not parallel. A light source is disposed adjacent to the light input surface and emits light into the light input portion. A specularly reflective layer is disposed adjacent to but not in intimate contact with the opposing side surfaces and reflects more than 80% of visible light incident on the specularly reflective layer.