T-rays to make better scanners.
A new way to create electromagnetie Terahertz (THz) waves or T-rays developed in research in Singapore and London could make better medical scanners.
Researchers from the Institute of Materials Research and Engineering (IMRE) in Singapore, and Imperial College London in the UK made T-rays into a much stronger directional beam than was thought possible, and have clone so at room-temperature conditions. This should allow future T-ray systems to be smaller, more portable, easier to operate, and much cheaper than current devices.
The scientists say that the T-ray scanner and detector could provide part of the functionality of a medical "tricorder" - a portable sensing, computing and data communications device - since the waves can detect biological phenomena such as increased blood flow around tumours. Future scanners could also perform fast wireless data communication to transfer a high volume of information on the measurements they make.
T-rays in the far infrared part of the electromagnetie spectrum have a wavelength hundreds of times longer than those that make up visible light. Such waves are in use in airport security scanners, prototype medical scanning devices and in speetroscopy for materials analysis.
T-rays can sense molecules such as those present in cancerous tumours and living DNA, as every molecule has a unique signature in the THz range. They can also be used to detect explosives or drugs, for gas pollution monitoring or non-destructive testing of semiconductor IC chips.
Current T-ray imaging devices are expensive and operate at only low output power, since creating the waves consumes large amounts of energy and needs to take place at very low temperatures.
In the new technique, the researchers demonstrated that it was possible to produce a strong beam of T-rays by shining light of differing wavelengths on a pair of electrodes - two pointed strips of metal separated by a lOOnm gap on a semiconductor wafer.
The structure of the tip-to-tip nano-sized gap electrode greatly enhances the THz field and acts like a nano-antenna to amplify the wave generated. In this method, THz waves are produced by an interaction between the electromagnetic waves of the light pulses and a powerful current passing between the semiconductor electrodes. The scientists tune the wavelength of the T-rays to create a beam that is usable in the scanning technology.
Lead author Dr Jing Hua Teng from IMRE said: "The innovation lies in the nano-antenna that we integrated into the semiconductor chip." Arrays of these nano-antennas create much stronger fields to generate a power output 100 times higher than the output of commonly used THz sources.
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|Date:||Feb 1, 2012|
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