Researchers at Northwestern University have developed a simpler way to generate single-chip terahertz radiation, a discovery that could soon allow for more rapid security screening, border protection, high sensitivity biological/chemical analysis, agricultural inspection, and astronomical applications.
The work, headed by Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science in the McCormick School of Engineering and Applied Science, was published Sept. 26 in the journal Applied Physics Letters and was presented in August at the SPIE Optics + Photonics conference in San Diego.
Terahertz radiation (wavelength range of 30 300 microns) can be used to see through paper, clothing, cardboard, plastic, and many other materials, without any of the health risks posed by current x-ray based techniques. This property has become extremely valuable for security screening, as it is safe to use on people and can detect metals and ceramics that might be used as weapons.
In addition, a scanning terahertz source can identify many types of biological or chemical compounds due to their characteristic absorption spectra in this wavelength range. Sensitivity to water content can also be utilized to study agricultural quality. Finally, through mixing with a compact coherent terahertz source, very weak terahertz signals from deep space can be detected, which may help scientists understand the formation of the universe.
Coherent terahertz radiation has historically been very difficult to generate, and the search for an easy-to-use, compact source continues today. Current terahertz sources are large, multi-component systems that may require complex vacuum electronics, external pump lasers, and/or cryogenic cooling. A single component solution without any of these limitations is highly desirable to enable next generation terahertz systems.
One possible avenue toward this goal is to create and mix t
|Contact: Megan Fellman|