Roland Piquepaille writes "Researchers from the Rensselaer Polytechnic Institute (RPI) have created a material that reflects virtually no light — or absorbs it like a black hole. They've built this new material by stacking layers of 'silica nanorods.' And they reached a refractive index of 1.05. This can be compared with 1.0 for air or 2.4 for diamonds. This coating, which is effective for all wavelengths, could be used for brighter light-emitting diodes (LEDs), more efficient solar cells, and new classes of 'smart' light sources that adjust to their environments. But don't expect to see your next glasses or the windshields of your cars protected with this coating: it's too sensitive to water and it would be destroyed by rain. Here is a link to more details and references about this anti-reflective coating."