Switching Lasers Off by Adding Energy
When you want more out of some system, normally you will try to put more in. More power to speakers can increase the volume and more voltage can increase stable clock speeds. With lasers however, it is not always that simple as researchers at the Vienna University of Technology have found a way to cause lasers to switch off by adding energy.
To keep theories and calculations simple, scientists will often assume situations are ideal. Mirrors do not actually reflect all light and energy is lost as photons travel along optical fibers, but ignoring that can make the math easier without compromising the results. When you do consider imperfect systems, you can find some very odd points in the calculations called exceptional points. Two years ago it was predicted that such a point would cause coupled lasers to switch off as more energy was added to them, and now the Vienna researchers have experimentally confirmed this.
For the experiment, the researchers used micro lasers less than a tenth of a millimeter in diameter, which can have their optical properties easily tuned. Potentially other coupled micro-lasers could be used to create electro-optical switches on chips.
Source: Vienna University of Technology