Laser brings sci-fi power to classroom

When most people hear the word "laser", they often think of something out of Star Wars or perhaps Dr. Evil's city-destroying death ray from Austin Powers. At Ohio State, lasers are not limited to science fiction.

OSU has opened a new $2.5 million departmental research area in the basement of the Newman-Wolfrom Laboratory called the Center for Chemical and Biophysical Dynamics. The centerpiece of this center is a $1 million laser system. The center was fully funded by the National Science Foundation, the Ohio Board of Regents and matching funds from several university departments. Although the center is up and running now, the official grand opening will take place sometime this autumn.

Dr. Terry Gustafson, associate professor of chemistry and director of the new center, said the new laser system is unique in the world and OSU is lucky to have it. He said pieces of the system exist in other places but only OSU has this particular combination.

"The laser system that we put together is a combination that's unique," Gustafson said. "I'm not aware of any other system like this in the world."

Gustafson said the new laser is used to study the structure and dynamics of molecules under an extremely short time scale. The laser is capable of measuring molecular changes in materials to femtosecond accuracy. A femtosecond is one-quadrillionth of a second or 10 to the negative 15th of a second. Each pulse from the laser is 30 to 40 femtoseconds in duration, an extremely short period of time.

"If you take 30 femtoseconds and compare it to one second, it's like comparing one second to one million years," Gustafson said.

Gustafson said the advantage of working on this short time scale is that it becomes possible for researchers to see the intermediate stages of chemical processes. In other words, while researchers might have a good understanding of the beginning and the ending of many chemical processes, there is still a lot to be learned about what actually happens during those processes. Using the new laser researchers can now, in essence, take snap shots of what is exactly happening during chemical reactions.

Gustafson's research is based on a small group of plastics called conductive polymers. The discovery of these materials led to a 2000 Nobel Prize in chemistry, and there is still a lot to learn about how they work.

Gustafson said these materials are plastics, which can act with certain metallic properties under certain conditions. Most notably, they can conduct electricity and give off light. Such plastics could be used for many commercial applications including the development of ultra-thin computer displays and TV screens. Conceivably, a thin sheet of plastic could make even today's flat-screen displays look bulky.

However, Gustafson's research is not about developing uses for these materials, but rather understanding how they work. Gustafson is using the laser to watch how the molecules in the polymers change, when they are conducting electricity. He hopes by understanding exactly what happens during the electroluminescent process, researchers can isolate certain steps that reduce the overall efficiency of the process. Increasing efficiency in these products would make them more energy efficient and lower the energy costs of their operation.

"Take for instance a portable computer with one of these electroluminescent polymer monitors," Gustafson said. "If we could make the materials more efficient, they could operate for 25 hours on a single charge instead of the four to six hours they get now."

The laser has many other uses other than studying electroluminescent conductive polymers. Dr. Bern Kohler, associate professor of chemistry, is using the laser to study how DNA interacts with ultraviolet light, particularly how DNA reacts to too much sun exposure.

"That's a problem that everybody has some experience with, because if you go out and spend too much time in the sun, your skin turns various shades of red and can really hurt," Kohler said. "There is plenty of evidence that if you get a lot of sun exposure over several years then you stand a good chance of developing skin cancer."

Kohler's research is focusing on how the DNA reacts to exposure with large doses of ultraviolet light. He is trying to find out how the DNA is damaged by the ultraviolet light, and how it defends itself from the damaging rays. Kohler said DNA is very good at dissipating the energy that is deposited in it by ultraviolet light.

"The DNA bases can eliminate this energy very quickly," Kohler said. "In fact, they do this on a femtosecond timescale. That allows the DNA to avoid sustaining any damage."

Kohler is using the laser to understand how the DNA is able to dissipate the energy so quickly.

Dr. Prabir Dutta, chair of the department of chemistry, is excited about what the new center brings to OSU. He said the center will be a valuable research and teaching tool for current student and will help bring in new undergraduate and graduate students.

"The center will have an impact on research covering development of new drugs, new materials and energy sources," Dutta said. "It will be an excellent resource for undergraduates desiring to do research with state-of-the-art equipment."