High speed response of a Hot Electron Bolometer to a picosecond optical THz source and to a THz QCL comb up to 31GHz

We have investigated the frequency response of a phonon-cooled Hot Electron Bolometer (HEB) made from an ultrathin superconducting niobium nitride film. We have used short optical pulses and a broadband spectrum analyzer to record the impulse response of the HEB. To interpret the experimental results, we have used numerical calculations based on the two temperature (2T) theoretical model.