Direct-detection characteristics of an 850-GHz Niobium-based superconducting SIS mixer

This paper presents the direct-detection responses of an 850GHz Niobium-based superconducting SIS (superconductor-insulator-superconductor) mixer measured with a Fourier transform spectrometer (FTS). The frequency response, current response rate, shot noise and equivalent noise power (NEP) of the SIS junction are calculated and analyzed. The experiment results are discussed in detail.