Oh, that!Faster than a Speeding Light Wave - UFO Evidence

Researchers have now measured many group velocities higher than c. "It's just not true what they say in the textbooks," says Raymond Chiao of the University of California at Berkeley. For example, a Gaussian shaped light pulse can travel faster than c through some highly absorbing materials. The explanation is that the central piece of the pulse is attenuated more than the earliest piece. Although the pulse shape is unchanged, it comes out smaller, and the "leading edge" of the input pulse is transformed to become the peak of the emerging pulse, a process called "reshaping." So no part of the pulse is actually transmitted faster than c, says Chiao.

That doesn't constitute a test of superluminal transmission of information, though I can imagine an experiment being designed on the basis of this phenomenon.

We have met the enemy, and he is us — Pogo