| The semiconductor superlattice parametric oscillator (SPO) generates a third harmonic field of a pump field. I will discuss the theoretical background of the SPO and present experimental results. A miniband electron performs, under the action of a microwave pump field, a strongly nonlinear motion due to Bragg reflections. The nonlinearity gives rise to generation of harmonics of the pump field and to paramagnetic oscillation. The theory allows it to find out the optimum working conditions of an SPO and provides the threshold condition for parametric oscillation. The SPO consists of a double-waveguide structure with a pump waveguide and waveguide resonator for the third harmonic. The SPO is suitable for upconversion of radiation in the 100 GHz to radiation in the 300 GHz range. Theoretical results indicate that upconversion of 1-THZ radiation to 3-THz radiation with an SPO should also be possible. Further experimental results show that an SPO is able to produce harmonic radiation up to the THz frequency range. The results manifest the extremely strong nonlinearity of the miniband transport. The superlattice frequency multipliers have the chance to compete with frequency multipliers (of the Schottky diode type) presently used for generation of monochromatic radiation in the sub-terahertz and terahertz frequency regions. |
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