Lin Zhu is receiving $1.4 million from the Department of Defense to address one of the central factors that keep diode lasers from becoming efficient, high-energy weapons.

Zhu, an associate professor of electrical and computer engineering, said his goal is to produce a light beam that has high power but that also goes in one direction, a difficult engineering challenge.

Lin Zhu works in his lab at the Advanced Materials Research Center after receiving a major grant from the Department of Defense.

Lin Zhu works in his lab at the Advanced Materials Research Center after receiving a major grant from the Department of Defense.

“You want lasers to go one direction for weapon application,” he said. “But for a lot of lasers you have to do some smart engineering to achieve that, especially when you want to increase the power.

“When the power increases, a lot of bad things  could happen to destroy that good beam quality of  diode laser output. Good beam quality means light goes in one direction. So it’s pretty challenging to get high power and good beam quality at the same time.”

The device Zhu intends to make would look similar to a computer chip and would convert electricity to light. For laser weapon applications, tens or hundreds of them would be stacked together.

What’s unconventional about Zhu’s work is that he and his team are using trench-like gratings that zigzag across a wafer to direct the light.

At less than half of a micron, the gratings are invisible except when viewed under high-powered microscopes. For scale, the width of a human hair is about 75 microns.

“We use gratings to guide light, to create interesting waveguides and interesting lasers so we can get  high power and  good beam quality at the same time,” Zhu said.

Zhu said that if he and his team can improve the technology that is now considered state of the art, it would be a success.

“The state of the art can get less than 10 watts from a diode laser system with good beam quality,” he said. “If we can improve that number by a factor of 10,   which would be great.”

Zhu is building on his prior research. He previously received a DARPA Young Faculty award and a grant through the Army Research Office’s Young Investigator Program. His most recent funding comes from Department of Defense Joint Technology Office High-Energy Laser Program.

Daniel Noneaker, chair of the Holcombe Department of Electrical and Computer Engineering, congratulated Zhu on his latest grant.

“The technology Dr. Zhu is creating has the potential to be more than evolutionary– it could be revolutionary,” Noneaker said. “This is well-deserved. Dr. Zhu and his team are well-positioned to contribute to the nation’s defense.”