Originally Posted by Penforhire
Ever heard of multicoated lenses and filters for cameras? There are coatings that transmit nearly 100% of incoming light (minimal difference between F-stop and T-stop values), albeit expensive. There are also constructions with negative (!) index of refraction. I do not believe the issue is physics, more like form factor and budget.
It's been a long time since I was studying this stuff, but at the time I learnt that any change of medium would cause light (or any electromagnetic wave, for that matter) to partially bounce, and partially go through. You can massage the numbers to minimize the bounce, using gradients or fancy materials, but my understanding is that you can't have a 100% transmission on the boundary. In physics, with the exception of superconductors, there is no "100% this way" or "100% that way".
Anyway, back on topic, I got myself a Nook Glow and really enjoying it, even with the physics limitations