U-M Researchers Develop Device for Weapon Detection


Researchers at the University of Michigan have developed a device that can “listen” for light waves that may one day be used for weapon and chemical detection at airports while allowing doctors and medical personnel to perform safer medical imaging.

The so-called T-rays, which are light waves too long for human eyes to see, will have several applications, says Jay Guo, U-M professor of electrical engineering and computer science. Among them, allowing airport security guards to find chemicals and other weapons and letting doctors image body tissues with less damage to healthy areas. It also could give astronomers new tools to study planets in other solar systems.

“We convert the T-ray light into sound,” Guo says. “Our detector is sensitive, compact, and works at room temperature, and we’ve made it using an unconventional approach.”

The terahertz range — which spans from radio waves that carry songs to receivers to gamma rays — includes microwave frequencies that cook food or transport cell phone signals, the infrared that enables heat vision technologies, and X-rays used in doctors’ offices.

While the terahertz band is “scientifically rich,” Guo says today’s detectors are bulky, need to be kept cold to work, or can’t operate in real time, which limits their usefulness for applications like weapons and chemical detection and medical imaging and diagnosis.

At U-M, Guo and his colleagues invented a way to convert terahertz light into ultrasound waves, and then transmit them. The response speed of the new detector is a fraction of a millionth of a second, which Guo says can enable real-time terahertz imaging in many areas.

A study about the project was recently published online in Nature Photonics.