| Abstract [eng] |
Semiconductor superlattices - quantum structures comprising at least one electronic minibands is the main object of the research for the particular thesis. The formation of the minibands features possibility of superior charge transport control making the superlattices an attractive media for the exploration of different physical effects. Superlattices are predicted to perform as terahertz (THz) and sub-terahertz (sub-THz) frequency range generators employing parametric generation or scattering-assisted inversionless Bloch gain mechanisms. Employment of the superlattices as small, tunable and efficient THz frequency sources has been discussed for a very long time, still, up to now no experimental evidence of the stable gain has been recorded. The particular thesis will provide the reader introduction into the long-lasting theoretical investigation and experimental achievements, supplementing an understanding on the significance of the further presented results. Thesis present evidence of the first experimental observation of the dissipative parametric generation in the DC and microwave biased GaAs/AlGaAs superlattice. Introduction of the large-signal gain model contributing to the evidence on the coexistence of Bloch and parametric gain in biased semiconductor superlattices expands the previously achieved understanding on the generation processes. Finally, the first experimental evidence on the stable Bloch gain in electrically biased GaAs/AlGaAs superlattice is described. |
