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This paper investigates fully integrated Terahertz (THz) Schottky detectors using silver (Ag) metallic nanowires (NWs) with 120 nm diameter as bridge contacts for zero-bias operating THz detectors based on highly doped Gallium Arsenide (GaAs) and Indium Gallium Arsenide (InGaAs) layers. The combination of InGaAs and metallic NWs shows improved performance at zero-bias than a GaAs based detector with a simulated capacitance of 0.5 fF and a series resistance of 29.7 $\Omega $ . Thus, the calculated maximum cut-off frequency of 2.6 THz was obtained for a NW contacted vertical InGaAs THz detector. Initial THz measurements were carried out using a common THz setup for frequencies up to 1.2 THz. A responsivity of 0.81 A/W and a low noise-equivalent power (NEP) value of 7 pW/ $ {~\sqrt {Hz}}$ at 1 THz were estimated using the measured IV-characteristics of the zero-bias NW-InGaAs based THz Schottky detector.

A fundamental limitation of the spectral response of laser-pumped fluorescent nanostructured media was considered in terms of a probabilistic model establishing the relationship between the enhancement factor of a spectral quality and characteristic propagation and amplification scales of pump light and fluorescence in the medium. It was shown that the minimum spectral width of fluorescent response of the pumped medium is limited by competition between the stimulated emission and radiation losses in microscopic fluorescence emitters associated with the speckles randomly modulating the pumping light field. Theoretical results were compared to the experimental data on the spectral properties of the fluorescent response of laser-pumped nanostructured “anatase nanoparticles—dye solutions” systems with various structural and optical properties. Rhodamine 6G and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) were applied as fluorescent components in the examined systems with various scatter volume fractions, which were pumped by pulse-periodic laser radiation with various intensities at 532 nm. Comparison showed a fair agreement between the theoretical and experimental results.