from the who-else-remembers-Chaos-Manor? dept.
To tame chaos in powerful semiconductor lasers, which causes instabilities, scientists have introduced another kind of chaos.
[...] Their technique, published today in Science, uses 'quantum chaos' to prevent the laser filaments, which lead to the instabilities, from forming in the first place. By creating quantum (wave) chaos in the cavity used to create the laser, the laser itself remains steady.
Professor Ortwin Hess, from the Department of Physics at Imperial, contributed much of the theory, simulation and interpretation of the new system. He said: "The way the optical filaments, which cause the laser instabilities, grow and resist control is for the laser a bit like the unruly behaviour of tornadoes. Once they form, they move about chaotically, causing destruction in their wake.
"However, tornadoes are more likely to form and move about over flat country. For example, in America they form frequently in beautiful Oklahoma but not as often in hilly West Virginia. The hills appear to be a key difference -- they prevent tornadoes from being able to form or move around.
"In the same way, by creating a 'hilly' optical landscape right inside our lasers using quantum chaos, we don't allow the filaments -- our optical tornados -- to form or grow out of control."
[...] To create a different kind of chaos -- the quantum chaotic landscape -- the team designed a new shape of cavity for the laser. Most cavities are cuboid in shape, but by using a D-shaped cavity, the team were able to induce quantum chaos in the light bouncing around.
This quantum chaos acts on a smaller scale than the wavelength of the light, creating the optical 'hills' that help to dispel the optical 'tornadoes'.
(Score: 2, Interesting) by Ethanol-fueled on Saturday August 18 2018, @08:14PM (1 child)
This makes a lot of sense. In the style of DUV light sources I previously worked with, the light was formed within thick metal chambers. They were a lot like engines, you had a top portion like a head, a bottom portion like a block, and instead of a "crankshaft" you had a very weird looking cathode/anode configuration running the length of the chamber (note: they way it worked was that gases were pumped into the chamber and ripping fuckhigh voltages through the gas caused the light to form and be directed out an aperture).
What was peculiar was how the interior of the chambers were textured. It was some serious alien-looking shit. The best way I can describe it is "scalloped" with smaller ridges parallel to the scallop texture. If you have a hard time visualizing what that looks like, look at the surface of the water in any 8-bit Mario game and you'll get a good idea.
(Score: 1, Interesting) by Anonymous Coward on Saturday August 18 2018, @08:25PM
Sounds like some kind of damping effect, texturing probably stopped some wave harmonics or something.