I recently attended the IRMMW-THz 2008 conference
at CalTech in which they theme of the conference is “Terahertz for Life” which represents the expansion of Terahertz research from optics and communications to include big physics and life science. Terahertz waves are now applied to chemistry, biophysics and medicine, as well as astrophysics and astronomy.
Terahertz extends from frequencies of 0.3THz (a wavelength of 1 mm) to 10 THz (30 micrometers) which offer unique imaging properties. The short wavelengths of terahertz rays provide enough spatial resolution for 3D micro imaging. Also, they don’t have physiological damaging effects as X-rays.
There are several ways to generate terahertz waves. Lasers are the preferred method. Laser light can control at a high level the spectral and temporal elements.
In the exhibit area were several companies with systems for controlling terahertz signals for commercial and research applications. There was Loeffler-Technology
which performs mm-wave imaging with terahertz signals for package inspection and security exploration. The demo unit showed a terahertz signal that could measure the both sides of a box with a single scan and thus providing a near 3D image of it. It could also detect hidden weapons such as a gun hidden underneath clothing. The product is called SynViewScan 300.
Another group called Toptica Photonics
which makes tunable diode lasers. Their research shows that the optical beat frequency of two slightly detuned CW lasers lies in the terahertz region. Through the accurate frequency control of two seed lasers, they can produce a narrow-band tunable terahertz beat frequency. Emcore
makes fiber optic equipment and uses terahertz in their systems for spectroscopy measurements.