Terahertz-The Next Frontier

Ray Peacock

Marketing professionals have almost rendered the word "revolutionize" meaningless. But in the case of terahertz time-domain spectroscopy, the original connotation holds true. The new technology will enable scientists and engineers to make measurements on, and obtain images of, material opaque in the visible and near-infrared regions of the spectrum. This capability is driving the recent explosion of interest in using terahertz imaging in manufacturing, quality control, and process monitoring. Consider the following developments.

Better Than X-ray
In the past few weeks, terahertz (THz or T-ray) technology, which involves the area of the electromagnetic spectrum between the infrared and microwave wavelengths, took two giant steps toward practical industrial application.

Mark Reid, a physicist from British Columbia, tested terahertz imaging as a way of investigating the internal properties of lumber. He was able to see images of the long cellulose fibers in far more detail than the simple dark patches that show density in an X-ray image.

If operators could see inside wood, they could make stronger products and get straighter lumber out of the timber harvested from our forests. And imagine what pest inspectors will be able to do with this technology when it gets to the price range of existing IR imagers. The way technology is moving, it could happen a lot quicker than the 30+ years it took IR imagers to evolve from a lab tool to one broadly used and favored by building and pest inspectors.

The science is still developing. With more and better tools, researchers such as Reid are scrambling to be the first to find an industrial application for the underdeveloped technology. Reid thinks T-rays could replace X-rays in imaging applications because they provide better images and do not involve ionizing radiation. Reid is now developing patents and working with Bruce Sutherland, of Wolftek Industries, in Prince George, British Columbia, to create camera-like devices using terahertz waves to see inside wood. The results of his research could well revolutionize the forest-products industry.

The Mini-Z
On the other side of the continent, Brian Schulkin, a doctoral student in physics at Rensselaer Polytechnic Institute in New York state, was awarded the first-ever $30,000 Lemelson-Rensselaer Student Prize. Schulkin invented an ultra-light, handheld terahertz spectrometer, called the "Mini-Z." By itself, this is an advance that could help catapult T-ray technology into the marketplace.

Wonder what would happen if these two physicists put their heads together? If you want to keep up with developments in T-rays, check out the Terahertz Science and Technology Network Web site. It's a great place to find out about the latest and greatest. The site also has an RSS newsfeed that you can add to a modern browser, such as IE7, Firefox, or tools published by Yahoo and Google.