Mike Wanke

The Next Generation of Screening Devices

Researchers at Sandia National Laboratories are developing the next generation of screening devices that will identify hazardous and toxic materials even if concealed by clothing and packaging materials. Working in the underutilized terahertz (THz) portion of the electromagnetic spectrum that lies between microwaves and infrared, a team of scientists intend to build a highly integrated miniaturized terahertz transmitter-receiver (transceiver) that could make a number of applications possible.

The project, the Terahertz Microelectronics Transceiver Grand Challenge, is in its second of three years of funding through Sandia's Laboratory Directed Research and Development program.

"The technology being developed can be used to scan for items such as concealed weapons or materials, explosives and weapons of mass destruction," says Mike Wanke, principal investigator. "In addition, we believe it will find applications in advanced communication systems and high-resolution radars.
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."

Wanke says over the past three years, "the terahertz situation has begun to change dramatically, primarily due to the revolutionary development of terahertz quantum cascade lasers."

These tiny lasers are 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 kg, or free electron lasers weighing tons and occupying entire buildings.

Quantum cascade laser-based systems can be smaller than the size of a baseball and powered from a nine-volt battery. Sandia has been a leader in developing this new technology and in collaboration with MIT is responsible for several world performance records for the lasers. Also, the lab and its partners are