Mikhail Kats, an assistant professor of electrical and computer engineering, received a prestigious CAREER award from the National Science Foundation for his efforts to tweak how substances emit light as they change temperatures. The work could someday offer a no-power means of heat regulation for satellite components and space-going vehicles or help to create camouflage materials that can hide from infrared cameras.
“The ability to thermally regulate with no power will be very important in space, for satellites or even interplanetary travel,” says Kats.
All materials have the capacity to shed some heat energy as light when their temperatures increase. The property—which is called thermal emission—accounts for most of the light in the universe, from the incandescent glows of light bulb filaments to twinkling starlight.
One particular parameter called emissivity governs how brightly objects glow, and Kats is working to create new and interesting objects with custom thermal emission properties.
For example, boosting emissivity with increasing temperature could lead to substances that offload excess thermal energy as extra light. Such radiator coatings could help satellites keep their cool without requiring any power sources.
Alternatively, objects engineered to have emissivity that decreases with temperature could be harder to identify using infrared cameras—potentially shielding troops from the artificial eyes of unmanned aerial assault vehicles.
Key to Kats’ efforts is an ability to measure thermal emission at relatively low temperatures. A lot of prior research on engineered thermal emitters has focused on the light given off by blisteringly warm objects as hot as 1,000 degrees Celsius, but Kats is trying to tune emissivities for substances at temperatures not far above room temperatures.
Performing such measurements at almost ambient temperatures, however, is technically challenging because of natural interference from objects surrounding the substance of interest. Kats and his students are working to develop new instruments and algorithms to ensure their calculations are accurate.
“We want to make sure we have the measurements down cold,” says Kats, noting that the techniques they develop will be tremendously useful to other engineers.
Kats is committed to sharing his advances with the broader research community and will make his low-temperature thermal emission datasets freely available for others to use. Additionally, he plans to communicate broadly by launching a podcast about applied physics and engineering with a special focus on UW-Madison’s contributions to the field.
The grant provides $500,000 of support over five years.
Author: Sam Million-Weaver