Computers that run on light
Contrary to what many think, science is as much about trying to break rules as it is about discovering them, and one of the "rules" which gets the most traction is Moore's Law.
Moore's law has been so accurate a prediction of the way silicon based computers evolve, that when faced with the challenge of breaking it, the best ideas are the most radical ones. From computers built on carbon-nano-tubules to quantum computers, to using black holes to run computations in another dimension (OK that last one is just Sci-Fi), we need to think outside the silicon box.
Computing using light is another out-of-the-box approach to break all barriers. Light as we have been constantly told, is the fastest thing possible. Nothing can go faster than the speed of light (except perhaps Tachyons).
Today, the fastest way to communicate involves sending light signals bounced off of satellites. Despite going across tens or hundreds of thousands of kilometers, light suffers only an imperceptible delay. This makes it a very lucrative replacement for electricity.
A computer is basically a collection of gates which control the paths in which current flows, and if we could find a way to do the same thing with light, we could see computers smaller, faster, lighter, than every before. Thanks to new research, we are now one step closer.