Coupling of terahertz radiation to two-dimensional plasmons in a resonant cavity via an on-chip integrated cross-dipole antenna

We present the responsivity spectra in the 0.2-0.4 THz range at low temperature of a AlGaAs/GaAs field-effect transistor connected to an on-chip integrated antenna. We fabricated asymmetric plasmonic microcavities to obtain down-converted signals from the intrinsic nonlinearity of 2D electron plasma oscillations. Finite-element modeling simulations of the 2D electron oscillations and electromagnetic calculation of the antenna spectral response suggest that the device may work as ultra-broadband nonlinear terahertz detector.