The theoretical analysis of the new microwave detector based on a Josephson heterostructure

摘要

We consider theoretically signal and noise properties of the new type of a high-sensitivity microwave detector, based on a SINIS (Superconductor-Insulator-Normal metal-Insulator-Superconductor) Josephson junction, in which the electron energy distribution function f(ε) in the nanoscale normal metal N region is nonequilibrium due to the capacitive coupling of this region with a receiving antenna. The deviation of f(ε) from the equilibrium leads to a change in the critical current I_c of the junction, i.e., in fact, to its inductance L = Φ_0/2πI_c (Φ_0 ≈ 2.07~*10~(-15) Wb is the magnetic flux quantum), which is the output signal of this device. Up to now there was no calculation of the noise properties of SINIS Josephson junction bolometer, taking into account non-equilibrium form of electron distribution function f(ε) in the normal metal absorber of this detector. We make this calculations and demonstrate, that noise parameter NEP of this detector is lower, than in others modern microwave detectors.