Study of Microwave Generation Utilizing Double-Stream Instabilities in Anisotropic Media

摘要

The report describes the theoretical and experimental investigation of the two-stream instability in bismuth, pyrolytic graphite, germanium, and silicon, as possible sources of radiation in the submillimeter to far infrared regions. The theory for the semimetals, Bi and PG, is concerned with the two-stream interaction of electrons and holes moving in opposite directions under the influence of an applied electric field. The theory for the anisotropic semiconductors, Ge and Si, considers the two-stream interaction of light and heavy electrons moving in the same direction. The band structure of these materials were incorporated into the plasma dispersion relations. The carrier velocity distributions were included by the use of the Boltzmann transport equation. The dispersion relations were numerically evaluated on a digital computer for the growth rate and the frequency of the instability for waves propagating in the principal crystalline directions. The results obtained by the present investigation clearly show that the details of band structure play a fundamental role in determining the character of two-stream instability in anisotropic solids. (Author)