Generation and detection of Terahertz radiation by field effect transistors

This is an overview of the main physical ideas for application of field effect transistors for generation and detection of Terahertz radiation. Resonant frequencies of the two-dimensional plasma oscillations in FETs increase with the reduction of the channel dimensions and reach the THz range for sub-micron gate lengths. When the mobility is high enough, the dynamics of a short channel FET at THz frequencies is dominated by plasma waves. This may result, on the one hand, in a spontaneous generation of plasma waves by a dc current and on the other hand, in a resonant response to the incoming radiation. In the opposite case, when plasma oscillations are overdamped, the FET can operate as an efficient broadband THz detector. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.