Controlling vortex motion and THz radiation in high temperature superconductors.

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During last five years I have focused on the very 'hot' topic of vortex dynamics --- Dr. A. Abrikosov got a Nobel Prize in 2003 for discovering the vortex lattice in type II superconductors. In contrast to a usual approach of studying vortex dynamics itself, I have concentrated on how to manipulate vortices in nano-devices. This proposal is based on my recent research and contains two main themes: (i) how to manipulate vortices in ratchet devices, (ii) how to generate, filter, detect, or amplify THz radiation using Josephson vortices in layered superconductors. Both of these topics were key subjects at recent vortex conferences (International Vortex Workshop 2005 http://www.tifr.res.in/~ivw10/ in India, VORTEX IV http://fys.kuleuven.be/vsm/projects/nes/Vortex%20IV%20abstractbook.pdf in Crete, ISS Tsukuba, 2005 http://www.istec.or.jp/ISS/ in Japan), at which I presented three invited talks this year. I have adequate experience to solve this problem because, on one hand, I have worked with top-experts (Prof. Fabio Marchesoni, Prof. Peter Hnggi) on the theory of stochastic processes and transport of small particles in noisy environments for four years and, on the other hand, I have also studied vortex dynamics (with Prof. L. Fisher, Prof. A. Rakhmanov, Prof. K. Kadowaki, Prof. F. Nori, Prof. A. Maeda, Prof. S. Bending) for more than ten years. Both themes of the proposed research are very important for applications: (i) it has been experimentally shown by Dr. R. Wnderberger that SQUID sensitivity strongly increases when using a ratchet device to remove vortices; (ii) the control of THz radiation is very important for various applications in astronomy, chemistry, biology and medicine, including THz imaging, spectroscopy, tomography, medical diagnosis, health monitoring, environmental control, as well as chemical and biological identification. Thus, this project, especially thanks to collaboration with experimentalists, can result in the development of new vortex ratchet & THz devices and, thus, have a big impact in improving the quality of life. The possibility of collaborating with experts on vortex dynamics and ratchet transport (Profs. S. Bending, Dr. S. Gordeev) and in nonlinear optics and photonic crystals (Prof. David Bird, Dr Dmitry Skryabin and the terahertz technology group) motivates my choice of the host organization.