Light exceeds speed of light

This is old news, but it was new news to me, which makes it news. That whole “If you didn’t know it, it’s news to you” bit applies, I suppose. Anyway – last year, some smarty-pants scientists showed some control over the speed of light in optical fiber. Slowing down light to 1/3 its natural speed was a noteworthy feat. But when the scientists were able to speed to light up to faster than the natural speed of light, well, that was phenomenal.

On the screen, a small pulse shifts back and forth – just a little bit. But this seemingly unremarkable phenomenon could have profound technological consequences. It represents the success of Luc ThÊvenaz and his fellow researchers in the Nanophotonics and Metrology laboratory at EPFL in controlling the speed of light in a simple optical fiber. They were able not only to slow light down by a factor of three from its well – established speed c of 300 million meters per second in a vacuum, but they’ve also accomplished the considerable feat of speeding it up – making light go faster than the speed of light.

This is not the first time that scientists have tweaked the speed of a light signal. Even light passing through a window or water is slowed down a fraction as it travels through the medium. In fact, in the right conditions, scientists have been able to slow light down to the speed of a bicycle, or even stop it altogether. In 2003, a group from the University of Rochester made an important advance by slowing down a light signal in a room-temperature solid. But all these methods depend on special media such as cold gases or crystalline solids, and they only work at certain well-defined wavelengths. With the publication of their new method, the EPFL team, made up of Luc ThÊvenaz, Miguel GonzalÊz Herraez and Kwang-Yong Song, has raised the bar higher still. Their all-optical technique to slow light works in off-the-shelf optical fibers, without requiring costly experimental set-ups or special media. They can easily tune the speed of the light signal, thus achieving a wide range of delays.

The article goes on to explain how this can have an important impact on light-processing systems for network switches and computers. In fact, it is important enough that the US Defense Advanced Research Projects Agency (DARPA) is investing heavily into continuing this research. Cool.

[tags]Light goes faster than the speed of light, Controlling the speed of light in optical fiber[/tags]

I never knew it could mean so much

This almost falls into my “Useless Knowledge” category, but there is enough good information for me to spare it that designation. While looking up the proper spelling and meaning of “gaffe” I found this entry on Wikipedia on the meaning of “error” instead. Learn the difference between an error in biology, baseball, computer science, statistics and so on. A quick and easy read with some interesting trivial knowledge attached.

[tags]Error, The many meanings of error[/tags]