Grischkowsky
Paige Worley Digital editor
An OSU professor has worked most of his life on a concept many people may benefit from but never need to understand.
Daniel Grischkowsky, Bellmon Professor of Optoelectronics, began studying terahertz frequencies in the early 90s, when even less was known about its potential. Terahertz frequencies, which are radiated as a laser, are a special frequency between microwaves and visible lasers.
His interest led him to pioneer into an unknown area. He began working to understand the laser's performance to develop a fundamental understanding of its characteristics, without knowing how it could be used.
“I have essentially spent my whole life in scientific and engineering problem solving,” he said. “That seemed to be a good match for me. I just want to understand things; the universe and where we are is really awesome.”
From Columbia to OSU
He began working with lasers at IBM Watson Research Center after graduating from Columbia with a Ph.D. in physics. By 1980, he was the manager of atomic physics with lasers, then became the manager of ultrafast science with lasers in 1983. With more competition in the 1990s, Grinschkowsky’s laser research was no longer a priority at IBM. He looked to continue it somewhere else, he said.
“One thing with me and lots of others like myself, we are not dominated by wanting to get rich or something like that, we enjoy professional practice and we are quite happy doing this,” Grischkowsky said.
OSU offered him a lab facility and funding for his research and graduate assistants. IBM gifted his equipment to the university. He packed up a truck delicately with his equipment and drove it straight to OSU, the same equipment he uses today.
Grischkowsky has used this Ultrafast Terahertz-Optoelectronic Laboratory in the Noble Research Center since 1993. After years of research he was still working with unknown areas.
“We were like explorers, what was there, well, we didn’t quite know,” Grischkowsky said. “We just broke through a big barrier, we poured through it, and while we were in there we looked around and said, ‘Hey, we can use this to solve that problem.’”
He didn’t know when he first started how understanding a terahertz laser could change anything. One of the biggest challenges was finding how to best use terahertz lasers to make his research practical.
“You want your research to have high impact,” Grischkowsky said.
The Advanced Technology Research Center at OSU was built in the mid-90s, and Grischkowsky and his team was one of the first to move in. He began working in a hallway in the basement, considered a state-of-the-art facility because of its unique characteristics, where he conducts all of his experiments on the laser.
“He was one of the first tenants of the ATRC, his occupancy was one of the foundations of the technology research center, in the basement there,” Associate Dean of Research Chuck Bunting said. “His research funding has been really solid, but what he contributes the most is the impact of his work.”
From the lab to the world
Grischkowsky wears his life in his office; publications, documents and loose-leaf papers stacked almost to the ceiling. Squeezed between two shelving units, a colorful flag of a bald eagle hangs, complimenting his souvenirs from trips he’s made to China to discuss his findings. Mounted on the only exposed wall are his certificates highlighting his award from his terahertz research.
When he started studying the world of terahertz frequencies, he wasn’t sure what he would find, he said. What he discovered was the radiations potential to enhance security, safety and data transfer. He likes breaking through barriers, but also keeping his work in perspective, he said.
“The planets and their orbits and everything is so precise, it’s not chaotic, and that’s an enormously humbling experience to understand that,” Grischkowsky said. “And this is not just technical details we are learning, we are learning about the foundations, so that’s a real big driver.”
He and his partners work in the ATRC lab measuring the laser performance in a variety of conditions. Mirrors are stationed strategically in the hallway with cement blocks and paper stacks supporting a few legs of each table.
Lime green linoleum floors lay on top of cement and gravel, to help prevent impacts of earthquakes and keep the ground stable. The mirrors are strategically set up to shoot the single laser 170 meters.
Grischkowsky and his team change the atmospheric characteristics of the hallway by sealing all the openings with painters tape and plastic wrap, then using home humidifiers to increase humidity and control air pressure. This plastic wrap allows the laser to penetrate into the hallway without letting the manufactured atmosphere enter the observation room.
“It turns out that with our set up and sample chamber, for that (this research) we are the best in the world,” he said. “It has certain innovations that other people haven’t managed to do.”
The researchers have changed the atmospheric conditions using theater-fog simulators, which are commonly used in plays. This simulates smoke or extremely foggy conditions, lowering visibility and creating a barrier for the laser. The terahertz laser went through that “like it wasn’t even there,” he said.
The modifications the team can make in the sample chamber, the hallway, is unique and extremely important to understand the laser, said Jim West, professor and interim head for electrical and computer engineering.
“Dr. Grischkowsky was one of the world leaders in generating the measurement of terahertz radiation, so that’s why the college and the department have always very strongly supported his work,” West said. “It’s ground-breaking, it’s revolutionary.”
There’s still not a lot out there about terahertz radiation because it’s harder to generate, unlike microwave or visible light lasers, West said.
But Grischkowsky has been able to identify the strengths and weaknesses of terahertz in a variety of conditions. He has identified possibilities for imagine through smoke, to enhance fire safety, as well as an increased capability in data wireless data transfer.
Grischkowsky’s research assistant, Mahboubeh Manvegar, has worked with him for five years. She specializes in identifying the communication potential with the laser, which may be able to double the speed and bandwidth of data transfer.
“For the next generation of wireless communication, this is a great opportunity to double up the bandwidth and the technology,” she said. “Like, a simple example is the way you use your phone you would have more ability to download more data with a faster speed.”
Currently, gigahertz frequencies are used to transfer data wirelessly. Terahertz could take the communication potential to a new level that’s 20 times faster, she said.
For now, Grischkowsky will continue experimenting on the laser in his lab in the basement of the ATRC, reporting his calculations and findings to the world. Grischkowsky knows implementing his findings in a business may be years away, but remains persistent in his work.
“That’s the payback, trying to make the future happen, and I got to participate,” Grischkowsky said.
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