Quantization of dielectric flux in phase-quantum-tunnel junction

The electrical properties of relatively long bridges made of very thin NbN film were investigated experimentally. When the bridge resistance
R_{b}\cong100\Omega
the I-V characteristic showed the possibility of quantization of dielectric flux inside the bridge. On the other hand, highly resistive bridges (
R_{b}\cong10
KΩ) revealed a step structure in the IV relation when irradiated by electromagnetic waves. Since the current interval of the steps is proportional to the frequency of the wave, these bridges are thought to behave as phase-quantum-tunnel devices with properties dual to those of Josephson junctions.