In principle, terahertz radiation—which lies between the microwave and infrared segments of the electromagnetic spectrum—could help people safely peer through flesh, plastic, fabrics and ceramics to detect anomalies, from tumors to bombs, for medical or security applications. But for decades, so-called t-ray devices were impractical outside the lab because they were fragile and because they weighed 45 kilograms (100 pounds) or more. Yet after just a few months of work, Brian Schulkin of the Rensselaer Polytechnic Institute created a rugged t-ray imager dubbed the “Mini-Z” that is less than 2.3 kilograms (five pounds) in weight and can fit in a briefcase. A prototype detected flaws purposely embedded in samples of foam used to insulate the space shuttle. Schulkin next plans to develop a handheld t-ray device.