From H. Kroemer and B. Lax to modern solid-state (semiconductor) cyclotron resonance masers

Presents an overview of mechanisms responsible for cyclotron resonance amplification in semiconductors as compared to that in the gyrotrons and a discussion of the ways to create beam-like and/or inverted distribution in the bulk of semiconductors by application of electric field is presented. Observation results on negative mass and light hole cyclotron resonance stimulated emission in Ge are discussed with the main emphasis on demonstration of the mechanisms responsible for the emissions. Some modern trends are also briefly considered.