http://www.mikroelektronik.fraunhofer.de/en/press-media/microelectronics-news/article/terahertz-wellen-kleinste-strukturen-fuer-hoechste-frequenzen.html
Ultrafast data transmission, detection of concealed weapons, or diagnosis of diseases – the range of potential applications for terahertz waves is enormous. Around the world, science and industry are working on developing electronic circuits for this previously largely unused spectral range. Fraunhofer IAF has set a European record by attaining a frequency of 0.66 THz.
- Integrated circuit with ultrafast transistors: thanks to a gate length of only 20 nm, IAF was able to achieve a record frequency of 0.66 THz.
Photo: Fraunhofer IAF
- Terahertz technology could make the search for people in a burning building much simpler. Photo: fotolia.de / Benjamin Nolte
Flames leap from the building and black smoke is rising. The fire department is already on the scene to fight the fire in the apartment building. Is anyone still inside? The heavy smoke makes it difficult to see and search for survivors. Terahertz technology, however, could make it much easier in the future for rescue teams to find people in burning buildings. Terahertz waves can penetrate smoke, dust, fog, and clothing – even from several hundred meters away. The electromagnetic waves are absorbed to different degrees by different materials, and do not damage the material. In combination with imaging techniques, an individual profile can be generated: a person can be detected reliably despite thick smoke.
Terahertz frequencies have great potential
The potential of the high-frequency range lies not only in rescue operations. Security personnel can discreetly detect persons carrying concealed weapons, even in a large crowd. Terahertz waves can be used to transmit large quantities of data over short ranges many times faster than is currently possible. Doctors can also see new possibilities in the diagnosis of diseases. The varied potential applications are one of the main reasons why science and industry are interested in opening up the high-frequency spectral range. The terahertz range – with frequencies of between 300 GHz and 3 THz and wavelengths of less than 1 mm and greater than 100 μm – lies on the electromagnetic spectrum between infrared and microwave. For a long time, terahertz waves were largely off-limits, because it was not technologically possible to manufacture electronic circuits that could use them. Transistors with high electron mobility and system architectures with many transmitting and receiving channels are needed to make use of the high-frequency range.
European record at Fraunhofer IAF
Researchers at the Fraunhofer Institute for Applied Solid State Physics IAF were the first in Europe to achieve a cutoff frequency of 0.66 THz. The record was attained using transistors made of III/V semiconductor structures (InGaAs/InAlAs) that give electrons an enormous drift speed. In conjunction with a transistor gate length of only 20 nm (approximately the length of a chain of 100 atoms), this made such high frequencies possible. Fraunhofer IAF in Freiburg is working closely in this field with the electronics company Sony Germany GmbH. “Over the next few years, we will work with our industrial partner to break the 1 THz barrier,” states Institute director Prof. Dr. Oliver Ambacher with confidence. In addition to the advantage of a high bandwidth, integrated circuits with fast transformers are of a very small size and have low energy consumption. Because they are also low-noise devices, they form the ideal technological basis for future terahertz systems. The technology is not yet mature enough to take advantage of the potential of high frequencies. The fire-fighter using a hand-held terahertz camera to find people in a burning house is still just a vision. But one that is moving closer.
Contact:
Fraunhofer Institute for Applied Solid
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