Saturday, January 02, 2010

Storing Light For 1.5 Seconds

Lene Hau and her group at Harvard has done it again! After demonstrating the ability to "stop light" several years ago, they now have shown that they can store that light for longer than milliseconds - this time, up to 1.5 seconds, which is LONG at the time scale that we are typically used to when dealing with light. You can also read more about this work here.

Now, one has to realize that we can "stop light" very trivially. Shine your flashlight onto a black surface, and voila! You've stopped light. However, what is done here isn't that. Stopping light, in this case, means that the light's energy AND PHASE, are somehow captured temporarily, and then it is then retransmitted later on. This can't be done when you stop light with a piece of paper, let's say, because you can't 'replay' what you had captured - most of the energy is lost in the vibrational energy of the stopping material. So that's why this "stopping light" experiment is different and not easy, and such a big deal. The ability to store and then replay exactly what came in is what makes it such an amazing feat.

Edit: This paper is available, "free-to-read" at the PRL website.


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