Direct measurements of tunable Josephson plasma resonance in the L-SET
  Phase dynamics has been measured in a driven mesoscopic Josephson oscillator where the resonance is tuned either by magnetic flux or by gate charge modulation of the Josephson inductance. Phenomena are analyzed in terms of a "phase particle picture", and by numerical circuit simulations. An analogy to switching of a DC-biased junction into voltage state is discussed. Operation principle of the recently demonstrated Inductive Single-Electron transistor (L-SET) based on the driven oscillator is reviewed. The obtained charge sensitivity implies that a performance comparable to the best rf-SETs has already been reached with the novel device. 
Mika A. Sillanpaa, Leif Roschier, and Pertti J. Hakonen