Shabahang and fellow graduate student Joshua Kaufman were working on just such a project, heating and stretching glass fiber on a homemade tapering machine. Shabahang noticed that instead of the desired result of making the center of the cable thinner, the material actually broke apart into multiple miniature spheres.
"It was kind of a failure to me," Shabahang said.
However, when Abouraddy heard what had happened he knew right away that this "mistake" was a major breakthrough.
While at MIT, Abouraddy and his mentor, Yoel Fink, a professor of materials science and current director of MIT's Research Laboratory of Electronics, said they were told by a theoretician that molten optical fiber should align with a process known as Rayleigh instability, which explains what causes a falling stream of fluid to break into droplets.
At the time, the MIT group was focused on producing fibers containing multiple materials. The team produced fibers by heating a scale model called a "preform" and stretching it apart much the way taffy is made. The process is known as thermal drawing.
Shabahang's experiment shows that by heating and then cooling multimaterial fibers, the theoretical became reality. Uniform particles that look like droplets are produced. Moreover, Shabahang demonstrated that once the spheres form, additional materials can be added and locked into place like LEGO building blocks, resulting in particles with sophisticated internal structures.
Especially significant is the creation of "beach ball" particles consisting of two different materials melded together in alternating fashion, similar to the stripes on a beach ball.
Kaufman, Shabahang and Abouraddy contributed to the Nature article
|Contact: Barbara Abney|
University of Central Florida