Modulation of self-resonant modes in NbCN/MgO/NbCN junctions by quasiparticle injection

In the submillimeter wave region, we have studied the modulation of self-resonant modes in NbCN/MgO/NbCN Josephson junctions (detectors). The tuning mechanism is based on the quasiparticle injection via an overlaid tunnel junction (injector). From the current-voltage characteristics of detectors, the maximum shift of resonant frequencies /spl Delta/f and Q factors due to electrode loss at the injected state Q/sub inj/ have been estimated to be /spl Delta/f/f(0)=0.11 and Q/sub inj/=100 at 470 GHz, where f(0) is the resonant frequency without quasiparticle injection. It is found Q/sub inj/ decreases with increase of the injector bias voltage.<
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