Plasmonic terahertz detector response at high intensities

Abstract

Recent work on plasmonic terahertz detection using field effect transistors (FETs) has yielded detectors with high responsivity. Therefore, deviation from small signal mode of operation, when the detector signal is simply proportional to the THz intensity, must be considered. This work presents a new analytical model to predict terahertz response in a FET at arbitrary intensity levels. The proposed analytical model was experimentally validated using a 0.13 μm InGaAs high electron mobility transistor and optically pumped CO2 gas laser operating at 1.63 THz of varying output intensities. The model is suitable for implementation in circuit simulators and might be used for device optimization and THz circuit design.

Nonlinear photoresponse of field effect transistors terahertz detectors at high irradiation intensities

“…Full triangles are the experimental data at gate voltage À0.1 V; dashed line is the fit of Eq. (1); dashed-dotted line is fitted using theoretical prediction14 Eq. (3), empty dots is R VI using the model(Eq.…”

AlGaN/GaN HEMT’s photoresponse to high intensity THz radiation

“…They are almost linear at the beginning and tending to square root dependence at high intensity in according to the theory [2].…”

“…The nonlinearity of the terahertz response at hig− her intensities was investigated in Ref. [2]. Experimental results reported in Ref.…”

“…2 an analytical model describing the intensity dependence of the terahertz response of a FET has been developed. The model predicts linear dependence of pho− toresponse on the radiation intensity followed by a square root dependence.…”

Response of plasmonic terahertz detectors to amplitude modulated signals

“…[4], relating surface electron density n and gate voltage swing U, n = CU/e where C is gate-to-channel capacitance per unit area, can be generalized to include the sub-threshold cases of negative U 0 [14,17]:…”