New terahertz source could strengthen sensing applications

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Current terahertz sources are large, multi-component systems that sometimes require complex vacuum

systems, external pump lasers, and even cryogenic cooling. The unwieldy devices are heavy, expensive,

and hard to transport, operate, and maintain.


Now Northwestern University’s Manijeh Razeghi has developed a new type of security detection device

that bypasses these issues. With the ability to detect explosives, chemical agents, and dangerous

biological substances from safe distances, the device could make public spaces more secure than ever.


“A single-component solution capable of room temperature continuous wave and widely frequency

tunable operation is highly desirable to enable next generation terahertz systems,” said Razeghi, Walter

P. Murphy Professor of Electrical Engineering and Computer Science in Northwestern’s McCormick

School of Engineering.


Director of Northwestern’s Center for Quantum Devices, Razeghi and her team have demonstrated a

room temperature continuous wave, highly tunable, high-power terahertz source. Based on nonlinear

mixing in quantum cascade lasers, the source can emit up to multi-milliwatts of power and has a wide

frequency coverage of one-to-five terahertz in pulsed mode operation.


Funded by the National Science Foundation, Department of Homeland Security, Naval Air Systems

Command, and NASA, the research was published on March 25 in Nature Scientific Reports. This new

research builds on Razeghi group’s many years of research with Northwestern’s Center for Quantum

Devices, including the development of the first single mode room temperature terahertz laser in 2011.


“I am very excited about these results,” Razeghi said. “No one would believe any of this was possible,

even a couple years ago. This initial demonstration was very exciting, and continuing developing will

lead us to the new frontier of terahertz technology.”



               Northwestern University