Plasma oscillations in field-effect transistor arrays

Terahertz (THz) plasmonic spectra of field-effect transistor (FET) arrays are discussed for two different types of FET arrays: (i) FET array with a common channel and a large-area grating gate, and (ii) array of FET units with separate channels and combined intrinsic source and drain contacts. It is shown that the coupling between plasmons and THz radiation in the FET array can be strongly enhanced as compared to a single-unit FET due to excitation of the cooperative plasmon mode distributed over the entire area of the FET array. The higher-order plasmon modes revealing the plasmon resonances at frequencies up to 20 THz can be excited much more effectively in the array of FET units with separate channels and combined source and drain contacts.