A new generation of sensors for detecting explosives and poisons could be developed following new research into a type of radiation known as T-rays, published today (3 February) in Nature Photonics.
The research shows that these T-rays, electromagnetic waves in the far infrared part of the electromagnetic spectrum that have a wavelength 500 times longer than visible light, can be guided along the surface of a specially designed material, known as 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 one of the areas with the most potential to use T-rays is security sensing and scanning, because many of the molecules in explosives and biological agents like anthrax strongly absorb this radiation. If T-rays are tightly confined on surfaces in contact with such molecules then the detection sensitivity is greatly increased.
Simple metallic surfaces have been used to control T-ray propagation before, but these only weakly guide the radiation, which extends as a weak field many centimetres above the surface of the material, thus rendering it less effective for sensing. The new study has now shown that a metamaterial surface draws T-rays close to it, creating a very strong field less than a millimetre above the surface. This greatly enhances the absorption by molecules on the surface making highly effective sensing techniques possible.
The study was performed by a team of UK and Spanish physicists led in the UK by Dr Stefan Maier from Imperial College London's Department of Physics, and Dr Steve Andrews of the University of Bath. Dr Maier explains why their metamaterial design is so important:
"T-rays have the potential to revolutionise security screening for
dangerous materials such as explosives. Until now it hasn't been
possible to exert the necessary control and guidance over pulses of t
|Contact: danielle reeevs|
Imperial College London