During the last decade, field-effect-transistor-based terahertz detectors (TeraFETs) have been developed to the competitive technology which enables a variety of new applications in the THz frequency range . Among the achieved state-of-the-art performance  TeraFETs can also exhibit a strong nonlinear response to intense THz radiation pulses . We show that the character of nonlinearity can be tuned by gate-to-source voltage from super-linear to saturation. We support this statement by experimental findings on TeraFETs fabricated in CMOS and GaN MMIC technologies using two different systems: a free-electron laser with ~20 ps THz pulses and a few THz cycle emission derived from a femtosecond Ti:Sapphire laser excited photoconductive emitter. Furthermore, the existence of a superlinear response regime can be supported using large-signal circuit modeling of antenna-coupled devices. This phenomenon can be employed both for THz autocorrelation measurement and to study the build-up time of rectified signal .
 G. Valušis, et al. MDPI Sensors 21.12, 4092 (2021).
 E. Javadi, et al. MDPI Sensors 21.9 2909 (2021).
 K. Ikamas, I. Nevinskas, A. Krotkus, and A. Lisauskas, Sensors 18, 3735 (2018).
 A. Lisauskas et al., APL Photonics 3, 051705 (2018).