Generation and Amplification of Radiation in Millimeter/Submillimeter Range through Current Driven Plasma Instabilities in Modulated Lower Dimensional Solid State Systems

摘要

We have introduced and studied new promising systems, which could lead to experimental verification and device applications of current driven plasma instabilities in lower dimensional solid state systems. These are: periodically modulated systems, quasi-1D bounded systems, and bounded systems with slab geometry. An interactive program for experimental verification of our results has been set-up with the Technical University, Vienna, Austria. The periodically modulated systems require significantly lower drift velocities compared to uniform systems to produce the plasma instabilities, bringing them within reach of experimental verification. In the bounded systems, with proper injection and extraction of carriers to maintain the desired non-equilibrium distribution, we obtain strong plasma instabilities, with a good chance for experimental observation. Possibility of population inversion in these latter structures is inferred by comparing our calculated I-V curves with the experimental curves. A decisive test for plasma instability in these structures is to look for radiation in the predicted frequency range. Such experiments, using bow-tie antennas, are planned for the near future. New formalisms were developed for the calculation of plasma instabilities in bounded systems (Energy Level Pairs Formalism), interlevel transport (self energy in random phase approximation), and extraction rates (transfer matrix poles).