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Topic Name: The waves terahertz now travelling far away
Category: Nuclear Magnetic Resonance
Research persons: Prof. Carlo Sirtori & His team
Location: U.F.R. Physics,Put 7008,10, street Domon Sorb-apple and Léonie Duquet ,75205 PARIS CEDEX 13, France
Details
The waves terahertz (10^12 hertz) can now be injected into optical fibres and transferred onto hundreds of kilometers without they being absorbed by the steam… It is thanks to a new technology developed by the team of Carlo Sirtori of the Materiaux laboratory and quantum phenomena (MPQ, CNRS/Université Paris 7) in collaboration with THALES R&T and the University of Cambridge (the United Kingdom). This work opens the way with important applications in the fields of medicine, safety, and the environment.
Located in the range of the remote infra-red, between the average infra-red and the microwaves, them waves terahertz1 remained ignored a long time. However their assets are very invaluable: able to penetrate in a broad not-conductive material range, they can pass through the skin, clothing, papers, wood, the paperboard and the plastic. Their properties open the door with very many applications: medical imagery, safety and environment (detections of pollutants, fingerprints, hidden weapons or of cocaine…) Emerged of the lapse of memory in the years 1990, their production was a real challenge. After ten years of research in technologies semiconductors, the waves terahertz started to be generated uninterrupted thanks to the development of the lasers with cascade quantique2 (QCL). However, the waves terahertz emitted by this technique are strongly absorbed by the molecules of steam, once transmitted in the air… To solve this problem and to be able to transmit the waves terahertz on hundreds of kilometers without they being absorbed, a new technique was developed by the team of Carlo Sirtori (MPQ, CNRS/University Paris 7, in collaboration with THALES R&T and the University of Cambridge).
Benefitting from ultradevelopes technologies of telecommunications, the researchers tried to bring them closer that of the QCL. They found how to register the waves terahertz on the invisible electromagnetic waves of telecommunications… By injecting a beam telecommunication in a laser cavity terahertz, the beam is propagated inside; it mixes with waves terahertz and keeps in memory their properties (phase and amplitude). Thus, at the exit, the researchers obtained a beam telecommunication which transports the waves terahertz for then injecting them into an optical fibre. The fibre protége the waves of the steam molecules and allows their transmission in the air on hundreds of kilometers… This discovery in advertisement of others… This work will make it possible to improve technologies of the lasers with quantum cascade thanks to those of telecommunications
About researcher:
Prof. Carlo Sirtori,
Materiaux et Phenomenes Quantiques
University Paris Diderot - Paris 7
Thales Research and Technology
Mél: carlo.sirtori@univ-paris-diderot.fr
Tel.: 06 84 86 58 54
Notes :
1) The waves terahertz have a frequency about some terahertz, and a wavelength ranging between 50 micrometers and 1 millimetre.
2) Technique based on a semiconductor laser of which the wavelength does not depend on the intrinsic properties of materials but of the architectural shape of the laser cavity. The structure of the cavity resembles a staircase where the electrons pass from one level to the other by emitting photons in the form of cascade.
References :
Terahertz transfer onto has telecom optical carrier. Sukhdeep S. Dhillon, Carlo Sirtori, Jesse Alton, Stefano Barbieri, Alfredo of Rossi, Harvey E. Beere & David A. Ritchie. Nature Photonics 1, 411 - 415 (2007) published in line on July 2, 2007
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