A light injector includes a tapered solid light guide having a light input end, an opposing light output end, and a total internal reflection surface defining a longitudinal outer surface there between. The light input end includes an aperture extending into the tapered solid light guide defined by an aperture surface. A specularly reflective layer or film is disposed adjacent to the total internal reflection surface. A distance between the specularly reflective layer or film and the total internal reflection surface defines a first air gap. The aperture is configured to accept a lambertian light source.