In a breakthrough, scientists have found that sulphur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles.
The team led by University of Arizona (UA) successfully took thermal images of a person through a piece of the new plastic.
By contrast, taking a picture through the plastic often used for ordinary lenses does not show a person's body heat.
"We have for the first time a polymer material that can be used for quality thermal imaging – and that's a big deal," said senior co-author Jeffrey Pyun, whose lab at the UA developed the plastic.
These lenses could be used for anything involving heat detection and infrared light, such as handheld cameras for home energy audits, night-vision goggles, perimeter surveillance systems and other remote-sensing applications.
The lenses also could be used within detectors that sense gases such as carbon dioxide, said senior co-author Robert A Norwood, a UA professor of optical sciences.
Some smart building technology already uses carbon dioxide detectors to adjust heating and cooling levels based on the number of occupants, researchers said.
In contrast to the materials currently used in infrared technology, the new plastic is inexpensive, lightweight and can be easily molded into a variety of shapes, said Pyun, associate professor of chemistry and biochemistry at the UA.
Norwood and his colleagues tested the optical properties of the new lens materials and found they are transparent to mid-range infrared and result in lenses with high optical focusing power.
The team's discovery could provide a new use for the sulphur left over when oil and natural gas are refined into cleaner-burning fuels.
Norwood said the new plastic is transparent to wavelengths of light in the mid-infrared range of 3 to 5 microns - a range with many uses in the aerospace and defence industries.
The study was published in the journal Advanced Materials.