Posted by Jamais Cascio
August 19, 2005 02:18 PM
Farnsworth: These are the dark matter engine I invented. They allow my starship to travel between galaxies in mere hours.
Cubert: That's impossible. You can't go faster than the speed of light.
Farnsworth: Of course not. That's why scientists increased the speed of light in 2208.
--Futurama, "A Clone of My Own"We may not have to wait two centuries. Researchers in Switzerland's Ecole Polytechnique Federale de Lausanne (EPFL) have developed a method of altering the speed of light in an off-the-shelf optical fiber. Their findings were published in the current Applied Physics Letters, and describe being able to reduce the speed of photons in optical fiber to below 71,000 km/s (the speed of light in a vacuum is approximately 300,000 km/s) as well as increasing photons to a speed "well exceeding the speed of light in vacuum." The press release isn't much more forthcoming than the abstract, noting only that "relativity isn't called into question, because only a portion of the signal is affected."
Much more attention is given to the ability to slow light. This is because, counter-intuitive though it may be, slowing down light could lead to significantly faster computers. Slowed-down light would allow for temporary "optical memory," allowing for routing and processing of optical computing signals without having to convert to electricity (which slows down processing considerably). The speed gained by not having to do conversion from light to electricity more than compensates for any speed loss from "slow light."
The attractive aspect of this development is that it uses off-the-shelf technology at room temperature, and doesn't require exotic materials or environmental conditions.
Now if someone can explain (a) how much faster than light they achieved, and (b) why this doesn't violate relativity?