New Technique Boosts Speed of THz Imaging

A new twist on terahertz imaging promises to speed inspections by a factor of 25. As a result, this technology has potential applications in airport security, narcotics investigations and electronic devices inspections.

An existing measurement technique. (Images: Fujitsu Ltd.)

At ~0.3 mm, terahertz waves lie on the spectrum of electromagnetic radiation between light and radio waves. They can penetrate nonmetallic materials such as paper, plastic, and textiles for nondestructive inspections and hold out the promise of showing an accurate picture of a subject, revealing hidden materials through nondestructive inspections. However, existing terahertz-based inspection methods can measure only a part of a substance with each exposure. Obtaining a complete picture of a target object requires incrementally shifting the target between repeated exposures, resulting in a time-consuming process.

Fujitsu Laboratories Ltd. has developed a new optical element, measuring 30 mm both horizontally and vertically, that obviates the need for moving the target and thus reduces overall inspection time from 34 min to 1 min 21 s.

The newly developed measurement technique developed by Fujitsu.

To measure the object without moving it, Fujitsu uses a terahertz wave and angled probe light beam, in the path of which a newly developed graduated mirror array with multiple levels is placed. As this technique produces results equivalent to those obtained when taking multiple exposures with incremental movements between each, it becomes possible to perform an inspection with just one exposure.

Fujitsu is working on even faster methods, with an eye toward commercialization around 2014, and it is proceeding with development for applications in manufacturing inspections.

For more information, visit: http://jp.fujitsu.com/labs/en