Electrical characterization of a superconducting hot spot microbolometer

We report on fabrication and electrical noise measurements of an antenna coupled hot spot microbolometer operating in vacuum at liquid helium temperature. A noise equivalent power (NEP) of about 40 fW/ Hz 1/2 has been measured at the output of a home made transimpedance amplifier operating at room temperature. This result shows the feasibility of microbolometers for a THz-range camera with a simplified electronic readout scheme.