We propose a terahertz (THz) plasmonic photoconductive antenna (PCA) with a record height of its metal electrodes of h = 100 nm and a high aspect ratio of h / p = 0.5 ( p is the period of the plasmonic grating) that can be used as a source is THz pulsed spectroscopic and imaging systems. We experimentally demonstrate that the power of the THz radiation generated by the proposed plasmonic PCA is two orders of magnitude higher than that of an equivalent ordinary PCA without a plasmonic grating. Current–voltage measurements of the thus developed plasmonic PCA under femtosecond laser excitation show that the photocurrent of the PCA increases 15-fold, up to i _p ≈ 1.2 mA. To reduce the leakage currents of the PCA, we propose a fabrication technology that is based on the etching of windows in a thin Si_3N_4 passivation dielectric layer deposited on the photoconductor surface, which makes it possible to reduce the dark current to i _d ≈ 5 μA.

We have demonstrated a quantum cascade laser (QCL) with a generation frequency of about 3.8 THz, grown by metal-organic vapor phase epitaxy. The multilayer heterostructure for QCLs consists of 185 repetitions of an active module containing four GaAs/Al0.15Ga0.85As quantum wells. The threshold current and threshold voltage of the fabricated QCL were 2.25 kA/cm2 and 19.7 V, respectively. The QCL was generated in the multimode regime, and the detection of terahertz radiation continued with an increase in the laser temperature up to 60 K.