MODULATION OF THZ RADIATION BASED ON THE SEMICONDUCTOR-METAL PHASE TRANSITION IN VANADIUM DIOXIDE
S.G. Bortnikov1, V.V. Gerasimov2,3, D.V. Dmitriev1
1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
3Novosibirsk State University, Novosibirsk, Russia
Keywords: modulation of THz radiation, vanadium dioxide, semiconductor-metal phase transition, Novosibirsk free electron laser
Abstract
The method of THz radiation modulation based on the semiconductor-metal phase transition in vanadium dioxide (VO2) is explored. Thermal heating of the VO2 film on the silicon substrate above the metallic state temperature results in ~80% reduction of THz radiation transmission. For two-electrode VO2 film structures with a millimeter-sized interelectrode gap, heating the film by electric current leads to ~42% transmission reduction only. At the same time, due to heating of the VO2 film substrate, a slow (seconds-running) cooling process and the reverse transition of the film to the semiconductor state occur. To increase the modulation frequency up to hundreds of kHz, it is proposed to create a structured system of separated micron-sized VO2-elements instead of a continuous film, which allows for much faster cooling of such elements confirmed experimentally.
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