T-rays to boost security

T-rays, electromagnetic waves in the far infrared part of the electromagnetic spectrum with a wavelength 500 times longer than visible light, can be guided along the surface of a metamaterial. Being able to control T-rays in this way is essential if this type of radiation is to be used in many real world applications. Researchers believe T-rays have high potential in security sensing and scanning, because many of the molecules in explosives and biological agents absorb this radiation strongly. If T-rays are tightly confined on surfaces in contact with such molecules, detection sensitivity is greatly increased. The study was performed by a team of UK and Spanish physicists, led in the UK by Dr Stefan Maier from Imperial College’s Department of Physics, and Dr Steve Andrews of the University of Bath. Dr Maier said: “T-rays have the potential to revolutionise security screening for dangerous materials such as explosives. We have shown that, with our material, it is possible to tightly guide T-rays along a metal sheet, possibly even around corners, increasing their suitability for a wide range of situations." Although metallic surfaces have been used in the past to control T-ray propagation, these only guide the radiation weakly. The new study has shown that a metamaterial surface creates a very strong field less than 1mm above its surface, greatly enhancing absorption by molecules on the surface. A metamaterial is a man-made material with electromagnetic properties that are impossible for natural materials to possess. The metamaterial created for this research consists of a metallic surface textured with a 2d array of pits.