There’s a certain part of the light spectrum that if you harness it, would allow you to see through walls and even through skin. It’s known as the terahertz radiation spectrum — or T-rays — and it falls between infrared and microwave. Detecting those tiny wavelength, sub-millimeter to be exact, has been a huge challenge. T-ray detectors typically need to be kept at extremely cold temperatures, as low as -452 degrees Fahrenheit. Unpractical for field applications, to say the least. But now a group of researchers from the University of Maryland has used graphene — an atom-thick sheet of carbon — as a sensor that can detect T-rays at room temperature.