Physicists from 25 countries meeting at K-State to discuss ultrafast laser research

July 13th, 2009

Kansas State University's world-renowned physics research with ultrafast intense lasers at the J. R. MacDonald Laboratory is drawing more than 200 top researchers from 25 countries to Manhattan for the second International Conference in Attosecond Physics from July 28-Aug. 1.

The first Attosecond Physics Conference took place in 2007 in Dresden, Germany, at the Max Planck Institute for Complex Systems. Because of the J.R. MacDonald Laboratory's reputation, K-State was chosen to host the second conference.

Dean Zollman, university distinguished professor and head of K-State's department of physics, said that despite the global recession, more than 200 scientists are expected to attend the meeting, and more than half of them are coming from abroad, including almost all of the leading research groups from Europe, Asia and Canada. He said that this conference series is the new forum for the advancement of attosecond technology and science.

Chii-Dong Lin, K-State university distinguished professor of physics and conference co-chair, said that attosecond physics aims at measuring the motion of electrons in atoms, molecules and matter in their own time scale. An attosecond is one billion-billionth of a second.

"When a referee in a football game wants to make sure that a close play at the end zone is a fumble or a touchdown, he often has to rely on viewing the slow motion taken by a TV camera in order to follow how the actual event occurred," Lin said. "In all sports, by analyzing the films, an athlete can learn how to correct his or her technique. Similarly, to know how a chemical reaction ends up with a specific product, the scientists would like to be able to make a 'molecular movie' so they can follow its reaction path and then they can control it."

Because chemical reactions are the consequence of the rearrangement of electrons in the molecules, and the changes in motion of electrons occur on the very short time of attoseconds, attosecond scientists study how to make such ultrafast cameras and how to make measurement with these cameras. Because the molecular movie is not a simple picture, the scientists also must learn how to read the signals taken by them.

Attosecond light pulses were first generated in the 21st century. Today there are only a handful of laboratories in the world capable of making attosecond light pulses. At K-State, Zenghu Chang, professor of physics and a conference co-chair, is a member of this group. Under the guidance of 10 teaching faculty at the J.R. MacDonald Laboratory, more than 60 graduate students, postdoctoral research associates, research faculty and laboratory staff are engaged in research using ultrafast lasers, with funding support from U.S. Department of Energy, Army Research and the National Science Foundation.

As the attosecond technology becomes mature in the future, it would enable scientists to control chemical reactions at the most fundamental level and move the present-day nanotechnology to a new level. K-State's research is expected to contribute an integral part to this effort, Zollman said.

Pioneers of the field are coming to K-State and are serving as the conference honorary chairs. They include Ferenc Krausz of the Max Planck Institute for Quantum Optics in Germany, Paul Corkum of National Research Council of Canada and University of Ottawa, and Katsumi Midorikawa from RIKEN in Japan.

Several K-State scholars will speak at the conference. Ahn-Thu Le, research assistant professor at the J.R. MacDonald Laboratory, will discuss using high harmonic generation to probe fixed-in-space molecular structures. Hiroki Mashiko, research associate in physics, will discuss the fast laser technique of double optical gating. Pedrag Ranitovic, former K-State research associate in physics, will discuss how using attosecond ultraviolet and femtosecond infrared radiation can probe the time dependence of the molecular dissociation process.

Source: Kansas State University