Sandia looks to the terahertz spectrum for next-gen explosives detection
Sitting between microwave and infrarerd, terahertz has long been neglected; technology is already used to detect chemical compounds in space, and so researchers look to miniaturize the system and create a library of spectral signatures
The terahertz portion of the electromagentic spectrum, sitting between microwave and infrared, has long been ignored in efforts to develop transmitter-receivers. No longer. A team of researchers at Sandia National Laboratories are now developing such a device as part of the lab’s Terahertz Microelectronics Transceiver Grand Challenge, and the goal is to create the next generation of explosives detectors. “The technology being developed in the Grand Challenge can be used to scan for items such as concealed weapons or materials, explosives, and weapons of mass destruction,” says the lab’s Mike Wanke. “In addition, we believe it will find applications in advanced communication systems and high-resolution radars.”
The timing is perfect. According to Wanke, over the last three years “the terahertz situation has begun to change dramatically, primarily due to the revolutionary development of terahertz quantum cascade lasers” — tiny semiconductor sources of terahertz radiation capable of output powers in excess of 100 mW. (Previously, such powers could only be obtained by molecular gas lasers occupying cubic meters and weighing more than 100 kilograms, or free electron lasers weighing tons and occupying entire buildings.) “However, the infrastructure needed to move the terahertz technology from the laboratory to the field is unavailable right now. We want to develop that infrastructure and invent the necessary technologies.”
The idea behind a terahertz-based explosives detection system is to identify the unique spectral signatures of individual compounds. This is not new — astronomers have long used the technology to identify chemicals emitted from stars — but such devices are often the size of washing machines and useless for active screening regimes. (A larger system could still be used for passive monitoring, however.) “We are very optimistic about working in the terahertz electromagnetic spectrum,” said Wanke. “This is an unexplored area and a lot of science can come out of it. We are just beginning to scratch the surface of what THz can do to improve national security.”
-read more in this Sandia news release
