23 January 2012
Star Trek Tricorder a reality? T-rays may hold the answer
Optical microscope picture of an antenna structure with the nano-antennas built into its centre (highlighted)
Following the X Prize Foundation's announcement that it will award $10million to anyone who can develop the Tricorder scanner used in Star Trek, researchers have unveiled a new technique to create Terahertz rays (T-rays) – the radiation technology behind full body security scanners.
According to the scientists, the new T-rays are stronger, more efficient and could be used to make better medical scanning gadgets, as well as potentially paving the way for innovations similar to the Tricorder.
The research is being undertaken by teams from Imperial College London and the Institute of Materials Research and Engineering (IMRE) in Singapore. According to the researchers, they have made T-rays into a much stronger directional beam than was previously thought possible and have produced them at room temperature conditions, enabling future systems to be smaller, easier to operate and much cheaper.
The T-ray scanner and detector, say the scientists, could provide part of the functionality for a portable sensing, computing and data communications device, since the waves are capable of detecting biological phenomena such as increased blood flow around tumours. Future scanners, they believe, could also perform fast wireless data communication to transfer a high volume of information on the measurements it makes.
T-rays are waves in the far infrared part of the electromagnetic spectrum that have a wavelength hundreds of times longer than visible light. Such waves are already used in airport security scanners, prototype medical scanning devices and in spectroscopy systems for materials analysis. As every molecule has a unique signal in the THz range, T-rays can sense molecules such as those present in cancerous tumours and living DNA. They can also be used in the non-destructive testing of semiconductor integrated circuit chips and to detect explosives or drugs in gas pollution monitoring. Currently, T-rays need to be created under very low temperatures with high energy consumption, while existing medical T-ray imaging devices have only low power output power and are very expensive.
In the new technique, the researchers demonstrated that it's 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 100nm gap on top of a semiconductor wafer. The tip to tip nano-sized gap electrode structure enhances the THz field and acts like a nano-antenna that amplifies the THz wave generated. The waves are produced by an interaction between the electromagnetic waves of the light pulses and a powerful current passing between the semiconductor electrodes from the carriers generated in the underlying semiconductor. The scientists are able to tune the wavelength of the T-rays to create a beam that is useable in the scanning technology.
The secret behind the innovation lies in a newly developed nano-antenna that has been integrated into the semiconductor chip. Arrays of the nano-antennas create much stronger THz fields that generate a power output 100 times higher than the power output of commonly used THz sources that have conventional interdigitated antenna structures. A stronger T-ray source renders the T-ray imaging devices more power and higher resolution.
Research co-author, Stefan Maier, Professor in the Department of Physics at Imperial College London, said: "T-rays promise to revolutionise 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 nanofabrication, 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 0.1µm into the electrodes, we have been able to make amplified waves at the key wavelength of 1000µm that can be used in such real world applications."
The study, funded under A*STAR's Metamaterials, is published in Nature Photonics.