No doubt this piece of news will beg the reader to ask, “Why does this matter?” The answer is how we will start then.
Researchers at the National University of Singapore and University of Innsbruck have taken a step towards making a transistor for light, instead of electricity. Using a modified form of a Fabry-Perot interferometer, they demonstrated a single atom acting like a mirror. The normal Fabry-Perot interferometer traps light between two mirrors. The mirrors are not perfect though, and a little bit of the light sneaks though them. As light escapes it is interfered with by the other light escaping, and the result, amplification or cancellation, depends on the distance between the mirrors. In this experiment, one of the mirrors was replaced with an atom. More importantly than an optical transistor, this experiment may greatly impact future cavity quantum electrodynamics, which may be at the heart of more optical devices than just transistors.