John Ballato of Clemson University said that making an optical fiber-based laser is equivalent to funneling a million laser pointers into an optical fiber the thickness of a hair.

“As the intensity of the light gets brighter in that fiber, the glass begins to say ‘uncle,’” Ballato said. “It’s not a surprise the

John Ballato (center) talks with two graduate students who work in his lab.

John Ballato (center) talks with two graduate students who work in his lab after receiving a major research grant from the Department of Defense.

materials are not doing what they are supposed to do.”

Ballato is working to create optical fiber that can withstand that intensity with $1.8 million from the Department of Defense Joint Technology Office High-Energy Laser Program.

Optical fiber, which is made of glass, ideally acts like a window with light going in and out. It works just fine for the conventional uses, such as transmitting information sent over the internet.

But when the light gets intense as it does in a weapon, the fiber begins to interact with the light in undesired ways, said Ballato, who is the J. E. Sirrine Textile Foundation Endowed Chair of Optical Fibers.

“The energy of the light that you want gets converted to energy of light that you don’t want,” Ballato said. “So the more power you put in it, the more it gets converted to other things. This has led to a plateau in the power that you can achieve. The material is beginning to get in the way.”

The solution for Ballato and his team is create a new material. They will try different combinations from the periodic table, using information they have gleaned from previous research.

Past research has focused on various properties of the material, such as sound and temperature, but they have been studied separately. The research Ballato and his team are doing as part of the new grant will study them altogether.

“Only now are we at a place of understanding both the physics and the chemistry of each one enough and how the material influences those to pull everything together into a single fiber,” Ballato said.

Ballato said his work could have an advantage over another method of increasing the power of lasers. In that method, tiny holes are created in the cross-sections of optical fiber to redirect the light.

But it’s difficult and expensive, Ballato said.

“Our approach could afford us an opportunity to go back to much, much more simple designs,” he said. “You would look at the end of this fiber, and you would think that it isn’t any different from any standard telecommunications fiber, except the portion of the fiber where the light is actually confined is a different material than it usually is.”

For Ballato, the funding is the latest in a series of grants from the High-Energy Laser Technology Program going back to 2011 and totaling nearly $7 million.

Rajendra Bordia, chair of the materials science and engineering department, congratulated Ballato.

“This is a great example of small investment paying off big time,” he said. “The continuity of sustained, high-level support is a testament to the high quality research from his group.”