  Terahertz light helicity sensitive photoresponse in GaAs/AlGaAs high electron
mobility transistors. The helicity dependent detection mechanism is interpreted
as an interference of plasma oscillations in the channel of the
field-effect-transistors (generalized Dyakonov-Shur model). The observed
helicity dependent photoresponse is by several orders of magnitude higher than
any earlier reported one. Also linear polarization sensitive photoresponse was
registered by the same transistors. The results provide the basis for a new
sensitive, all-electric, room-temperature and fast (better than 1 ns)
characterisation of all polarization parameters (Stokes parameters) of
terahertz radiation. It paves the way towards terahertz ellipsometry and
polarization sensitive imaging based on plasma effects in
field-effect-transistors.
