A unique material seems to disconnect the temperature of the object from the thermal radiation it generates, which can be a new way to hide infrared cameras.
In short, everything with a temperature above absolute zero emits heat radiation. In general: the higher the temperature, the brighter the radiated light.
However, due to the bizarre nature of the material of the nickel oxide quantum material, the new findings are a surprising exception to these sustainable physical principles.
In new research, scientists have discovered that a nickel-nickel oxide can reverse the thermal trend that almost all solids exhibit because it does not necessarily emit light when heated.
“Normally, when you heat or cool a material, the resistance changes slowly,” explains Shriram Ramanathan, a material engineer at Purdue University.
“But for a nickel oxide, the resistance will change from an insulating state to a conducting state in an unconventional way, leaving the thermoluminescence characteristics virtually the same over a certain temperature range.”
Because the thermal imaging camera works by detecting thermal radiation, similar materials that can mask the thermal signal of an object can hide the object and make it invisible to the heat.
The new study is not yet in place, but researchers say they will one day learn about nickel-nickel oxide, in addition to understanding other methods of manipulating thermal signals to increase the visibility of objects. It also not only reduces it.
The research team wrote in a new article: “We have shown that in the temperature range around 30 ° C the radiation is the same regardless of the temperature.”
“This is the first time that temperature-independent thermal radiation has been demonstrated, which has a significant impact on infrared camouflage, privacy protection and heat radiation.”
In the experiments, the researchers heated many sample materials to temperatures between 100 and 140 ° C and measured their thermal radiation in long-wave infrared.
Waffles composed of sapphire, fused silica and carbon nanotube bunch show significant differences in heat radiation when heated to higher temperatures, but regardless of the increase in heat, wafers covered with the nickel oxide film remain the same. .
In the image above, the nickel oxide test, labeled ZDTE, is an abbreviation for Zero Differential Thermal Emitter (ZDTE): a material that can break the conventional one-to-one image between object temperature and thermal emission capacity.
As shown, nickel oxide has largely become ZDTE within this limited temperature range. Note that the small bright spots in the ZDTE row show a portion of the sapphire wafer that is not covered with quantum material to illustrate the comparison of thermal emissions between the treated and untreated wafers.
A lot of work still needs to be done before we can actually use it to sneak in on infrared cameras, but as the research team indicates, the possibilities are enormous.
The author wrote: “The ability to decouple temperature and heat radiation through our simple design allows new methods to hide large areas of thermal signals, such as portable personal privacy technology, and also has an impact on the thermal management of the room”