3 POST-DOC RESEARCH ASSOCIATES EXPLORING TINY WORLD IN UTSI LABS

Three young scientists from very diverse places in the world have joined the team at The University of Tennessee Space Institute’s Center for Laser Applications (CLA) to do laser-related research.

While their projects overlap, Drs. Yelena White of Kazakhstan, Lino Costa of Portugal, and Xiaoxuan (Shaun) Li of China apply lasers to different areas of research.

White, who earned her doctorate in physics at Vanderbilt University, is concentrating on micro-machining, including creating nanochannels and waveguides in glass.

“We would like to create a ‘lab-on-a-chip’ device,” she said. “A device like that will contain many reservoirs, interconnected by different size nanochannels. Nanochannel machining is a difficult task, involving the application of ultra-short pulse lasers capable of delivering high-energy pulses.”

A molecule in a nanochannel “behaves much like it would in its natural environment – for example, in a cell,” White explained. “It is very hard to measure single molecule fluorescence unless it is confined in a small space.” Her research has applications in the physical, pharmaceutical, and medical fields.

Li earned his Ph.D. in Materials Science and Engineering at the University of Connecticut at Storrs, where he studied for six years in laser materials processing. He is focusing on fabrication of nano-channels that will be integrated into a Single Molecule Detection (SMD) device. He also is involved in Laser Induced Surface Improvement (LISI) methods for modifying surfaces of metals.

“We are trying Electron Beam lithography (EBL) to create nano-channels in fused silica wafers in order to evaluate the bonding process of wafers with nano-channels,” he said. In the future, he plans to try another approach, using a femto-second laser, to achieve the same results.

Costa is modeling the LISI process, using finite element analysis to calculate residual stresses. Two other experimental areas of his work involve developing new coatings for LISI applications -- including a coating based on nano diamonds.

“LISI processing of nanodiamond-coated low carbon steel has shown promising results,” he said.

His research in yet another field – “rapid manufacturing” involves laser fabrication of three-dimensional objects by adding and consolidating controlled amounts of a powder form feedstock material in a layer-wise manner. He is finishing his Ph.D. dissertation at the Technical University of Lisbon in Materials Science and Engineering.

The three young researchers anxiously await the arrival of a femto-second laser system that has been ordered for CLA. A “clean room,” an environmentally controlled dust-free facility, is being prepared in anticipation of the arrival of this new equipment.

Dr. William Hofmeister, research professor and CLA director, recruited the three post-doc research associates. He explains that a femto-second is a million times smaller than a nano-second, which is one-billionth of a second.

“We hope these post-docs stick around for at least 10 to the power 26 atto-seconds (three years),” Hofmeister jokes. Their comments about him and the Space Institute indicate the youthful scientists just might do that.

“Our research area holds a lot of potential,” White said. “Other groups all over the world are doing similar research. To get to the frontiers, we must go above and beyond what has already been done. The competition is tough, but Dr. Hofmeister is a very motivated person. This helps a lot.”

“It is good to work with people who are motivated and who can motivate others,” added Costa.

“UTSI is a very good institute to do research,” said Li. “I had an offer from Purdue University, but their projects are traditional. This is more challenging with a new frontier and (the opportunity to use) nano-fabrication, which is quite an innovative technology. It is inspiring here with many new and different ideas, and looking at new things and combining different fields like single molecule detection. You can really see the effect of combining electron beam photography with femto-second micromachining with fluorescent detection technology. All these are very interesting fields.”

“It was a lucky coincidence,” Yelena says about her coming to UTSI. She knew Hofmeister “in passing” at Vanderbilt. Dr. Joseph Majdalani, a UTSI professor and husband of her friend Inna, suggested she contact Hofmeister, who had moved to the Institute. She did and joined the Institute in November.

Li and Costa both met Hofmeister at professional conferences. Costa joined the CLA staff in October, and Li arrived in January.
 

Examining the micro-stage for performing laser micro-machining of various materials are, from left, Drs. Yelena White, Xiaoxuan (Shaun) Li, and Lino Costa, new scientists in UTSI’s Center for Laser Applications.
 

Drs. Lino Costa, left, Xiaoxuan (Shaun) Li, and Yelena White, post-doctoral research associates in UTSI’s Center for Laser Applications, check out a Rofin Sinar 3000 CO₂ laser system.
 

-- UTSI Photos
 

Writer: Weldon Payne (931) 393-7222
wpayne@utsi.edu