A Comparison of Laser Oscillators and Quasiclassical Solid State Oscillators
We present three types of quasiclassical oscillators that are able to generate microwave radiation of high frequency: Gunn oscillator (used as source of radiation up to ∼ 200 GHz); superlattice oscillator (in development, up to 200 GHz); and resonant-tunneling diode oscillator (demonstrated up to 700 GHz). These oscillators are solid state oscillators, driven by active can be media. An active medium of a solid state oscillator makes use of the nonlinear transport in a semiconductor (Gunn oscillator) or in a semiconductor heterostructure (superlattice oscillator and resonant-tunneling diode oscillator). The nonlinear transport is due to a negative mobility of conduction electrons. The origin of a negative differential mobility is of quantum mechanical nature. However, the transport can be described classically.