New T-rays could lead to Star Trek 'Tricorder' medical scanners

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Scientists are finding that there's more to milk from the infrared part of the electromagnetic spectrum.

Researchers from the Institute of Materials Research and Engineering (IMRE), a research institute of the Agency for Science, Technology and Research (A*STAR) in Singapore, and Imperial College London have made Terahertz (THz) waves, or T-rays ,into a much stronger directional beam than was previously thought possible. That opens up the possibility for futuristic medical scanning gadgets like the Star-Trek style 'Tricorder,' a portable sensing, computing and data communications device (see image on right).

The breakthrough, published recently in the journal Nature Photonics could lead to new T-ray imaging systems that are smaller, more portable, easier to operate, and much cheaper than current devices.

T-rays (a.k.a. terahertz radiation) are increasingly used in full-body security scanners found in airports. Unlike X-rays, they have less photon energy that can damage biological tissue and DNA. They are capable of detecting biological phenomena such as increased blood flow around tumorous growths.

Current T-ray imaging devices, however, are pricey and have to operate at low output power. That is because creating the waves, which are hundreds of times longer than waves that make up visible light, consumes large amounts of energy and must take place at very low temperatures.

To get around these challenges, the researchers turned to a new "nano-antenna" technique.

To produce the T-rays, the researchers shine light of differing wavelengths on a pair of electrodes made with two pointed strips of metal separated by a 100-nanometer gap on top of a semiconductor wafer. This structure greatly enhances the THz field and acts like a nano-antenna to amplify the wave generated. The THz waves are produced by the interaction between the electromagnetic waves of the light pulses and a powerful current passing between the semiconductor electrodes. The result is a tune-able T-ray with a power output that is 100 times greater than the power output of commonly used THz sources.

Research co-author Stefan Maier, a visiting scientist at A*STAR's IMRE and professor at Imperial College London, sums it up:

T-rays promise to revolutionize medical scanning to make it faster and more convenient, potentially relieving patients from the inconvenience of complicated diagnostic procedures and the stress of waiting for accurate results. Thanks to modern nanotechnology and nano-fabrication, we have made a real breakthrough in the generation of T-rays that takes us a step closer to these new scanning devices. With the introduction of a gap of only 0.1 micrometers into the electrodes, we have been able to make amplified waves at the key wavelength of 1000 micrometers that can be used in such real-world applications.

Source: Imperial College London