“I want to show you a mineral,” says Mikhail Kats.
The University of Wisconsin–Madison Jack St. Clair Kilby Associate Professor of Electrical and Computer Engineering points to a likeness of Bucky Badger – actually two Buckys – appearing through a translucent crystal. The crystal resting in front of a photo of the singular mascot is responsible for the UW–Madison icon’s duplication in the graphic, and was used as an example by Kats and a team of photonics experts to find something that doubles images even better, a material called barium titanium sulfide.
Light moves at different speeds throughout the stone depending on the polarization, or direction along which the electric field is pointing. And while there are plenty of geological specimens that cause double vision, barium titanium sulfide does it in the mid-infrared at almost 10 times higher than any other known Earthly solid.
“This work is an example of how characterizing optical materials is foundational to discovery,” Kats explains, describing his efforts to build up extensive capability for optical measurement. “If you look closely enough at new materials, interesting things almost inevitably fall out.”