Eden receives Harold E. Edgerton Award

Harold E. Edgerton, who was an electrical engineering professor at MIT, is one of ECE Professor James Gary Eden’s heroes. And this year, Eden received an award named for Edgerton’s.

Eden is the 2010 recipient of the Harold E. Edgerton Award from SPIE, the international society for optics and photonics. The award is given  annually for outstanding contributions to optical or photonic techniques in the application and understanding of high speed physical phenomena. Eden received this award for his “contributions in demonstrating optical techniques for observing physical phenomena, including his seminal work in atomic, molecular and ultra fast spectroscopy,” according to the SPIE Web site.

"It is no surprise that SPIE has selected Prof. Gary Eden for the Edgerton Award,” said ECE Professor Kanti Jain. “Gary's well-known work is highly regarded in the quantum electronics community. He has pioneered an array of pulsed laser techniques for ‘freezing’ the interaction of atoms and molecules, and in the spirit of the work of Harold Edgerton, Gary has developed optical techniques to observe physical phenomena that were not accessible previously. This award is a most deserving honor for Gary. "

“Edgerton took some photos that you can only describe as jaw-dropping, exposing a world that perhaps people imagined, but were not capable of seeing before,” Eden said.

In the mid-20th century, Edgerton photographed objects using strobe lamps that emitted a pulse of light about one-millionth of a second in duration. The resulting photos froze objects in motion, such as the crown created when a drop of milk hits a surface or the spray of an apple as it is pierced by a bullet.

“Because the award is named in Professor Edgerton’s honor, I am grateful to have been named a recipient because I have great respect for his work,” Eden said. “Our research is in the same spirit as Edgerton’s.”

But Eden’s experiments occur on a time scale that is a factor of 10 million shorter than those of Edgerton decades ago.

Eden and his research team are working with pulses of light that are on the order of one-ten-thousandth of a billionth of a second.

“With pulses that short, we’re able to freeze the motion of atoms and molecules,” Eden said. “Whereas Edgerton froze the movement of a macroscopic object, like a bullet or a drop of milk, we’re able to do the same thing with atoms and molecules.”

In one experiment, a pulse of light is used like a pair of scissors to cut the chemical bond of a diatomic molecule. A second pulse of light allows the researchers to observe the motion of the two as they move away from each other.

“At the atomic or molecular level, we can observe the basic dynamics of the atom or molecule,” Eden said.

In another experiment, they have been able to watch one atom interact with another over a long distance, again with pairs of pulses.

The first ultra-short laser pulse forces an atom to ring like a bell or a tuning fork at about 20-40 terahertz. Known as quantum beating, this “ringing” can be detected with a second laser pulse, and the frequency of the oscillations can be measured precisely. As the second atom approaches the first, there is a long-range force between them. That interaction causes the tuning fork frequency to change slightly—less than a tenth of a percent.

“By monitoring the frequency of the tuning fork, we can map out the interaction between that incoming atom and the oscillating atom,” Eden said.

At the intersection of optical physics and physical chemistry, Eden’s research is geared toward understanding the fundamental aspects of atoms interacting with each other.

“It’s impossible to control what we don’t understand,” Eden said. “Once you understand the details of how atoms interact at long range, then you can focus on ways to steer the interaction so as to selectively yield a given product.”

Eden is not sure exactly where the research will lead, but predicts being able to control the outcome of a chemical reaction in the future.

“It is opening doors to worlds we never knew existed, or we may have expected that they existed, but we couldn’t get in the door,” Eden said.