In ground-breaking work, Lene Hau made light slow down to a cycling speed. Dick Ahlstromreports
'Stop the lights" took on a whole new meaning earlier this year after some amazing experiments conducted at Harvard University by physicist Prof Lene Vestergaard Hau.
She devised a way to take a pulse of light travelling at its usual 299,792,438 metres per second and slow it to an astounding 0.055 metres per second. Prof Hau then reconstituted the light beam at a new location and it continued on its merry way at its original speed.
Prof Hau, who many believe is very likely to receive a Nobel prize for her discoveries, visits Dublin next week to deliver a lecture about her work.
She is a member of the governing board of the school of theoretical physics within the Dublin Institute for Advanced Studies and comes to Dublin because of these connections.
In effect, she found a way to change the high-speed light pulse into a slow moving packet of matter and then back into the original light pulse.
This was done using something called a Bose-Einstein condensate, an unusual state of matter created using supercooled clouds of sodium atoms.
These atoms pack together and lock into step. The light pulse hits the condensate and is compressed by a factor of 50 million into matter. This slows it down as it moves at a crawl across to a second Bose-Einstein condensate. Once there, a flash of a laser converts the matter back into a replica of the original light pulse.
The achievement has implications for a range of technologies, particularly future computers that use light rather than electrical pulses to handle and move information. Light is very difficult to modify but matter is easy to change.
Information could arrive as light, be modified as matter and then travel on as light carrying new information.
•Prof Hau's talk is free and open to the public and takes place at 3pm on Wednesday, May 16th, in the Schrödinger Lecture Theatre in the Fitzgerald Building, Trinity College, Dublin. It is located near Trinity's Lincoln Place entrance