This story is from the category Display Technology
Date posted: 27/05/2014
A device that essentially listens for light waves could help open up the last frontier of the electromagnetic spectrum—the terahertz range.
So-called T-rays, which are light waves too long for human eyes to see, could help airport security guards find chemical and other weapons. They might let doctors image body tissues with less damage to healthy areas. And they could give astronomers new tools to study planets in other solar systems. Those are just a few possible applications.
But because terahertz frequencies fall between the capabilities of the specialized tools presently used to detect light, engineers have yet to efficiently harness them. The U-M researchers demonstrated a unique terahertz detector and imaging system that could bridge this terahertz gap.
"We convert the T-ray light into sound," said Jay Guo, U-M professor of electrical engineering and computer science, mechanical engineering, and macromolecular science and engineering. "Our detector is sensitive, compact and works at room temperature, and we've made it using an unconventional approach."
The sound the detector makes is too high for human ears to hear.
The terahertz gap is a sliver between the microwave and infrared bands of the electromagnetic spectrum—the range of light's wavelengths and frequencies. That spectrum spans from the longest, low-energy radio waves that can carry songs to our receivers to the shortest, high-energy gamma rays that are released when nuclear bombs explode and radioactive atoms decay.
The terahertz band is "scientifically rich," according to Guo and colleagues. But today's detectors either are bulky, need to be kept cold to work or can't operate in real time. That limits their usefulness for applications like weapons and chemical detection and medical imaging and diagnosis, Guo says.
Guo and colleagues invented a special transducer that makes the light-to-sound conversion possible. A transducer turns one form of energy into another. In this case it turns terahertz light into ultrasound waves and then transmits them.
See the full Story via external site: ns.umich.edu
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