Parametric excitation of plasma oscillations in Josephson junctions

Abstract

Experiments on a Josephson junction analog showed a parametric excitation of the plasma resonance. The experimental conditions were that the junction was dc biased in the supercurrent mode, and that the applied rf-power exceeded a certain threshold value depending on the circuit losses. The frequency of the applied rf was approximately twice the plasma frequency. The observed half harmonic generation with big amplitude may be understood from a discussion of the stability properties of the Mathieu differential equation