Plasma-Wave Detectors for Terahertz Wireless Communication

We report on terahertz wireless communication experiments at 0.3 THz using 250-nm gate-length GaAs/AlGaAs field-effect transistor (FET) as a detector and unitraveling-carrier photodiode as a source. The physical mechanism of the detection process is terahertz wave rectification on nonlinearities related to overdamped plasma oscillations in the transistor channel. We present an experimental study of rectification bandwidth and show for the first time that room-temperature direct detection with modulation bandwidth of up to 8 GHz can be achieved, thus showing that nanometer-sized FETs can be used as valuable detectors in all-solid-state terahertz wireless communication systems.