CEFS laser surface modification creates buzz at international conference

Researchers at the University of Nebraska-Lincoln College of Engineering used a first-of-its-kind laser in the United States to develop a specialized method of surface modification they believe can be revolutionary in manufacturing fields.

When Craig Zuhlke and George Gogos, co-directors of the Center for Electro-Optics and Functionalized Surfaces (CEFS), and student researchers presented their work on femtosecond laser surface processing (FLSP) at a major international conference recently, it created quite a buzz.

Zuhlke and Gogos each presented 30-minute "tech talks" at the Institute of Electrical and Electronics Engineers ITherm Conference in May in Denver, Colorado. They focused on femtosecond laser processing and discussed various applications of FLSP and its capability to enhance heat transfer. FLSP was also central to five conference papers featuring research conducted at CEFS. Students gave 15-minute presentations of those papers.

Zuhlke said the reaction of colleagues was much more enthusiastic than the Nebraska researchers had expected.

"Going to a conference like this, you can see the direct impact FLSP is having by all the feedback from everyone," Zuhlke said. "Our talks were heavily attended. Typically, they reserve a few minutes after each talk for questions from the audience, and they had to cut off the discussion after our talks, which is a good thing because these (were) the top experts in this area, and we learned how important they think FLSP is going to be.

"Our talks were also referenced by a lot of the other tech talks, where they brought up some of the work that we were doing, kind of addressing this as the future of thermal management."

In FLSP, an ultrafast laser is beamed at a metal material, changing its micro- and nanoscale features and its chemistry. These changes confer properties conducive to a wide range of applications in space, defense, medicine and beyond. This technique offers advantages over traditional surface modification methods.

Nebraska researchers have been at the leading edge of functionalizing surfaces with lasers for about two decades, Gogos said, but traditional, complex methods and available technology allow for production of only small amounts of raw materials with tailored surface properties.

Now, with a Tangor 300 laser and the FLSP technique, CEFS researchers have overcome the biggest hurdle to widespread industrial use – scalability. Gogos said FLSP will be instrumental in the production of larger quantities.

"A lot of people create textured surfaces to enhance heat transfer, but they're not scalable and they're not permanent," said Gogos, Wilmer J. and Sally L. Hergenrader Professor of Mechanical and Materials Engineering. "What we're offering is a technology that offers scalability and permanency, and that's why people on the heat-transfer side are so excited by FLSP."

Zuhlke said thermal management is "the bottleneck of modern electronics."

"How do you get more powerful electronics and higher densities? You need to be able to cool those devices," Zuhlke said. "We showed that FLSP can have a big impact.

Gogos said feedback indicates that many researchers, agencies and companies are interested in possible collaborations with CEFS.

"The organizers (of ITherm) must have seen the uniqueness that we have and how it can be a manufacturing method of the future, and they decided they wanted to expose FLSP to the thermal and heat-transfer communities," Gogos said. "We had the opportunity to present this method to both industry and academia, and it went well."