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When Mark Freeman,'81 BSc, talks about "fast," the word takes on a whole new meaning. Not pizza delivered to your door in under 20 minutes. Not the time it takes for a Garth Brooks concert to sell out. Not even how quickly your paycheque goes when the January bills roll in.
In Freeman's laboratory at the University of Alberta, "fast" is measured in terms of picoseconds and femtoscconds. Imagine a pulse of light so fleeting that its duration —30 femtoseconds— is to one second what one second is to a million years, and you begin to appreciate tile meaning of "fast" in the Context of Freeman's work.
The University of Alberta physicist is doing novel work combining incredibly fast pulse of laser light with microscopes capable of seeing things not much bigger than an atom. He is thereby able to observe — and record — phenomena never seen before.
Along the way, he's become the maker of the world's fastest movie: a 20-second flick that shows what happens when a tiny magnet records two bits of data on a computer hard drive. The movie, which is recorded at about 20 billion frames a second— a billion times faster than a Hollywood production—will never be box office, but it's got people looking.
Industrial ramifications
"The type of work Mark is doing is very innovative Work that borders on new physics and also has strong technical and industrial ramifications," says John Samson, the Physics Department chair. Already five Fortune 500 companies have used Freeman's laboratory to test prototypes, and he's involved with an American consortium on a four-year project aimed at storing 100 billion bits of data on one square inch — that's roughly 100 times tile density of the current state-of the-arc computer disks.
Besides tantilizing the computer industry, Freeman's work has caught the eye of the National Sciences and Engineering Research Council. The Council has awarded him a 1999 Steacie Fellowship, an award given annunlly to promising Young researchers. The prize, worth $ 180,000 over two years, will free Freeman from his teaching duties, allowing him to give greater attentiun to his research.
That research has roots in Freeman's longtime fascination with lasers, and the work that he did in graduate school at Cornell University in New York. While earning master's and doctoral degrees there, he worked with Cornell's low temperature physics group investigating the properties of superconductors. But he never forgot his fascination with lasers and jumped at tile chance to do postdoctoral Work with a laser group at IBM's research division in Yorktown Heights, New York.
Combining expertise
Since accepting a faculty position at the U of A five years ago, Freeman has been combining his expertise with lasers and his curiosity about low temperature phenomena, in particular superconductivity — the loss of all electrical resistance that happens in some metals, alloys, and compounds when chilled below some critical temperature, typically just above absolute zero.
"We want to look in detail at the process by which an object becomes a superconductor," says Freeman. "There have been many studies done when these substances are in equilibrium — either as an ordinary metal or as a superconductor — but there has to be some dynamical process by which they go from a metal to a superconductor."
Freeman wants to he the first to observe that transformation. It is to this end that he has developed his ultrafast moviemaking technique. His "camera" is a special kind of electron microscope that uses a stylus, somewhat analogous to the needle of an old-fashioned record player — except that this needle is infinitely more sensitive, capable of following the profiles of individual atoms. While this extremely powerful microscope — known as a scanning tunnelling microscope — lets Freeman makes observations at the atomic level, things happen very quickly here. "As a general trend, as things get smaller their characteristic time scales increase"says Freeman.
And that's where the incredibly fast pulses of laser light come in. The general principle is simple enough, as Freeman shows with an ordinary household fan. He switches it on, and the blades quickly become a blur. Then he turns on a strobe light, and the blades appear to slow. And when the cycling of the stroke light matches exactly the rate at which the fan blades are turnings, the blades appear to freeze.
It has taken Freeman the better part of five years to develop the technique for bringing together the precision of scanning tunnelling electron microscope with what is "essentially the world's fastest strobe light," and he relishes the thought of being able to devote himself fully to applying that technology — as the Steacie Fellowship will allow him to do. During its two-year term, he hopes to make some memorable movies.
Lights - really fast lights. Camera. Action.
Published Spring/Summer 1999. |
