Scientists in Australia have created a tiny device that could transform the way we detect pollution, monitor health, and identify different materials.
The new technology is an electrically adjustable infrared filter that is small enough to fit on a chip, potentially replacing much larger and more expensive sensing systems.
The device was developed by researchers from The University of Western Australia and The Australian National University.
Their findings were published in the journal Advanced Materials Technologies.
The new filter works in the long-wave infrared region of light. This is the type of invisible radiation that all objects around room temperature naturally give off.
Traditional thermal cameras use this radiation to create images based mainly on heat. They can tell which objects are warmer or cooler, but they usually cannot identify what the objects are made of.
The new technology goes a step further. It can detect specific patterns of infrared light that different substances emit. These patterns act like unique signatures or “fingerprints” that can help identify gases, chemicals, and materials.
Lead author Oleg Bannik, a Ph.D. candidate at UWA’s School of Engineering, compares the technology to human vision.
“Our eyes combine red, green, and blue light to see colors,” he explained. “In a similar way, this technology can compare several carefully selected infrared wavelengths. Instead of simply seeing hot and cold areas, it may be able to distinguish between different substances that look identical in an ordinary thermal image.”
For many years, infrared spectroscopy—the technique used to identify materials by their infrared fingerprints—was mostly limited to laboratories, military equipment, and large industrial systems. The equipment was often bulky, expensive, and required a lot of power.
The new device is much smaller. It is made from thin layers of gold and silicon that contain extremely tiny holes. The layers are separated by a very small gap. By changing this gap electrically, the researchers can control which infrared wavelengths pass through the filter.
One surprising finding is that changing the gap by only a few hundred nanometers—far smaller than the width of a human hair—can significantly alter the behavior of infrared light with wavelengths around 10 microns.
The technology could have many practical uses. One of the most promising applications is environmental monitoring. The device may help detect methane leaks and industrial emissions more quickly and efficiently. Since methane is a powerful greenhouse gas, better detection could support efforts to reduce climate change.
The technology could also improve industrial safety and thermal imaging systems. In medicine, researchers believe it may eventually help doctors detect inflammation, monitor wound healing, and identify subtle changes in body tissues that ordinary thermal cameras cannot see.
Because the sensors are lightweight and use little power, they could also be installed on drones and portable devices. In the future, a handheld infrared detector or a drone carrying one of these tiny sensors could help identify pollution, inspect industrial sites, or even assist with medical screening in remote locations.
