T-rays — the next wave in imaging technology

A versatile technology that can spot cracks in space shuttle foam, while also offering the potential to see biological agents through a sealed envelope and detect tumors without harmful radiation, will be the focus of a full-day symposium at the 230th national meeting of the American Chemical Society in Washington, D.C. The session will be co-chaired by T-ray experts Xi-Cheng Zhang, a physicist and engineer at Rensselaer Polytechnic Institute, and Charles Schmuttenmaer, a chemist at Yale University. T-rays are the next wave in imaging and sensing technology. Based on the terahertz (THz) region of the electromagnetic spectrum — defined by frequencies from 0.1 to 10 THz, just between infrared light and microwave radiation — T-rays are opening the door to a wide variety of applications.

Objects at room temperature emit thermal energy in the THz range. This radiation is extremely useful for sensing and imaging objects, with major advantages over other techniques, according to Zhang. T-ray systems offer more than just images: they can provide valuable spectroscopic information about the composition of a material, especially in chemical and biological species — something that X-rays may not be able to do. T-rays are also safer than X-rays for biological applications, Zhang says, with photon energies that are 1 million times weaker than X-ray photons.

Until recently, researchers have had great difficulty harnessing the potential of the THz region, largely because of a lack of suitable radiation sources. Zhang will demonstrate new advances achieved at Rensselaer that allow for the sensing of extremely small objects on the nanometer scale, as well as at large distances of more than 100 meters — an essential improvement for national security applications such as remote sensing of explosives. He will also discuss recent collaborations with NASA, where THz imaging successfully detected defects in space shuttle foam.

Advanced materials research has provided new and higher power sources, and interest in THz sensing and imaging has exploded as a result. “Biomedical imaging and genetic diagnostics are two of the most obvious potential applications of this technology,” Zhang says. “But equally promising is the ability to investigate material characteristics, probe distant galaxies, and study quantum interactions.”

Science Daily
September 27, 2005

Original web page at Science Daily