Chaotic lasers might sound like a screen-annihilating powerup from "Shooting Shoot-Game R-Type-Galaxia", but they could instead prove vital in simulation and security. As well as sounding totally bad.
Computers can follow set instructions incredibly rapidly but they suck at generating random numbers. They have to generate "pseudorandom" numbers according to set algorithms. John von Neumann said that "Anyone who considers arithmetical methods of producing random digits is, of course, in a state of sin. Worse, anyone who wants to base their internet security on a known program is existing in a state of stupdity.
Humans are even worse, even if we could do it fast enough. Think of a number from one to ten.
Not one of you will have said one or ten, despite that being twenty percent of the available range, and that's just one of the fantastic number of failings in our ability to be unpredictable.
Natural phenomena are instead used to harness true randomness - atmospheric noise, nuclear decay - but Japanese scientists have come up with a tabletop laser which already generates random numbers ten times as fast, and could go up to a hundred.
An external reflector is used to direct some laser output back into the original laser. Movies may tell you that this will just cause the whole thing to blow up (and stop chasing Flash Gordon), but what it really does is turn the laser into a chaotic system. The laser is already light bouncing between to set mirrors - adding the extra component creates a known but utterly unpredictable chaotic system, whose output light levels are a constant source of truly random numbers.
The system can already generate 200 megabytes of utterly random gibberish per second, meaning that just one system could replace all of livejournal, or generate one Pussycat Dolls album every quarter of a second.
Ideally we'd just use lasers to eliminate both of those things directly, but alas, miraculous as the modern world is, it isn't perfect.
Posted by Luke McKinney.
Random Laser http://www.physorg.com/news148660964.html