Parametric instability in the resonance detector of terahertz radiation based on FET with cylindrical gate electrode

A possibility of the parametric instability in the resonance detector of the modulated terahertz radiation is analyzed. The detector represents a system of capacitively coupled plasma and mechanical resonators. A layer of 2D electron gas with a relatively high electron mobility and a cylindrical gate electrode that is fixed at the ends serve as the first and second resonators, respectively. The method of coupled oscillations is used to obtain the dependence of the minimum threshold pump power of the plasma circuit that corresponds to the excitation of the parametric instability on the main geometrical and electric parameters of the system.