Terahertz plasmonic field effect transistors for imaging applications

Terahertz (THz) imaging technology applications require fast electronic devices with high responsivity, good selectivity, and large bandwidth. Field Effect Transistors operating in the THz or sub-THz range and using the rectification of plasma waves satisfy these requirements. InGaAs-based, GaN-based, and Si nanostructure arrays of plasmonic devices (referred to as TeraFETs) compete for plasmonic THz imaging applications. Depending on the channel size and the electron mobility, TeraFETs could operate in three different plasmonic regimes - collision-dominated, ballistic, and viscous with the highest modulation frequency reaching the sub-THz range of frequencies. Another advantage of TeraFETs as imaging elements is a wide dynamic range - from relatively low intensity signals up to the high intensity impinging THz beam causing the excitation of nonlinear plasma waves, such as shock waves or solitons propagating in the device channels. The TeraFETs could achieve resolution down to the nanometer scale. The plasmonic electronics technology might become a dominant THz electronics technology and support sensing, imaging, and communications at THz frequencies