In April 2007, a team of physics researchers at Kansas State University started experimenting with an idea to make faster, more powerful and efficient laser-like soft X-rays. In less than a year, they've proven that their idea works.

Manhattan, KS - infoZine- Kansas Light SourceThe K-State physicists have worked out a more efficient and accessible method for creating ultrafast light pulses. These pulses are key to research that aims to study fast dynamics in atoms and molecules. This kind of technology would lead to new methods for imaging and identifying molecules.

First, scientists need to do experiments with light sources whose pulses are so fast that they are measured in attoseconds -- that's one quintillionth of a second. Zenghu Chang, professor of physics, and a team of researchers at K-State have been working on a better way to create these fast pulses. K-State is receiving an annual grant from the U.S. Department of Defense of $1.25 million for three years with a possible two-year extension.

To get the pulses needed for attosecond research, physicists have had to create soft X-ray pulses from short infrared pulses. The problem with the previous methods, Chang said, is that only a few labs in the world are able to do this. The process also can be fragile, he said, because what might work one day won't work another. Plus, Chang said this method is inefficient -- you put in a lot more energy than you get out.

As an alternative, Chang and the researchers at K-State have worked out a method to get soft X-ray pulses from long infrared pulses. Because the infrared pulses in this method are longer, the researchers needed a way to control the process to get the desired short soft X-ray pulse. Using a process they dubbed double optical gating, they came up with a switch to turn the process off and on.

"It's kind of like a light switch, but it goes very, very fast," Chang said.

Their work appears in the March 14 issue of Physical Review Letters and also was published in Physical Review A and Applied Physics Letters.

"We think this is a relatively big step in the field of attosecond research," Chang said. "Using a longer infrared pulse, more researchers can now work on attosecond research. In the past, only two or three labs could do it with isolated pulses. Now it's relatively easy to create such pulses."

Chang said that the advancements they've made in attosecond research reflect the growing prestige of K-State's James R. McDonald Laboratory, which seven years ago switched its focus to fast-pulse lasers. Several graduate students working on the project have been asked to present at important conferences, Chang said. In summer 2009, K-State will invite researchers from around the world to Manhattan for a conference on attosecond research.

"We are able to do first-class research here," Chang said.

Other K-State faculty members involved in the research include Lew Cocke, university distinguished professor of physics; Shuting Lei, associate professor of industrial and manufacturing systems engineering; and Chengquan Li, research associate at the Macdonald Laboratory; and Hiroki Mashiko, research associate in physics.

K-State graduate students involved in the work, all of Manhattan and all doctoral students in physics, include Steve Gilbertson, Sabih Khan and Eric Moon.

K-State's partner institutions in the work are Texas A&M University and the University of Ottawa.