Advantaged of THz and far infrared cameras

Security applications have strong market potential

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VTT and the Millimetre Wave Laboratory of Finland (MilliLab) are developing a new architecture for thermal sensors to enable a simpler and more affordable way of producing the far infrared and THz cameras that are used in various security applications. The project is being financed by the European Office of Airforce Research & Development, EOARD, an affiliate of the United States Air Force. Other project partners include Lockheed-Martin Solar and Astrophysics Laboratory.

The market potential for THz imaging is enormous, especially with regard to different security applications. Other possible commercial applications could be found in medical imaging and process analytics as well as in space sciences. THz, or terahertz radiation, covers the frequency range between the infrared and microwave portion of the spectrum.

For explosives and narcotics detection

The technology being developed enables passive imaging, which means that the sensors detect THz radiation emissions of, for example, a human body without using separate sources of radiation to illuminate the target. These sensitive sensors improve the precision of surveillance at a distance of tens of meters. The detection technology not only covers different metals but also other material, enabling the detection of hidden narcotic substances or explosives. It also speeds up and improves security checks.

Innovative concept

The biggest challenge facing the developers of the equipment was to transfer these sensitive sensors into large sensor matrices. The innovative concept developed by VTT and MilliLab combines sensitive thermal sensors and micro-electromechanical MEMS switches. This new sensor - called bolometer - is designed to function in the same way as the CCD cells of a digital camera. In CCD cells the charge carries detached by the radiation are integrated in a condenser, where this accumulated charge is read out with a charge-sensitive preamplifier. A similar concept is being developed in this project, apart from the fact that these sensors accumulate heat, not charge.

VTT is also developing a true THz camera for security imaging applications. However, this camera is based on a different sensor architecture.

 


Additional information

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