The article seems very loose with its terminology which makes it really confusing. For example:
> Albert Einstein and just about every other physicist insisted that light travels 186,000 miles a second in free space, and that it can't be speeded-up or slowed down. But in 1998, Hau, for the first time in history, slowed light to 38 miles an hour, about the speed of rush-hour traffic.
Hau did not slow down light in free space so this has nothing to do with Einstein's statement.
What I would like to know is, is underlying fundamental mechanism here similar to or the same as what we know as refraction? From all the descriptions it sounds awfully similar, other than the extreme(!) nature of the slowdown.
Light can NOT be slowed down - at all! What happens with refraction is the light is absorbed by matter, then re-emitted, over and over, which effectively slows it down.
In this case the material that absorbed the light takes a very long time to re-emit it.
> Albert Einstein and just about every other physicist insisted that light travels 186,000 miles a second in free space, and that it can't be speeded-up or slowed down. But in 1998, Hau, for the first time in history, slowed light to 38 miles an hour, about the speed of rush-hour traffic.
Hau did not slow down light in free space so this has nothing to do with Einstein's statement.
What I would like to know is, is underlying fundamental mechanism here similar to or the same as what we know as refraction? From all the descriptions it sounds awfully similar, other than the extreme(!) nature of the slowdown.