Evidence of non-bolometric mixing in the bandwidth of a hot-electron bolometer

The gain bandwidth of a superconducting NbN hot-electron mixer was measured at local oscillator (LO) frequencies 2.5 THz, 0.6 THz and 0.3 THz and compared to presently known bolometric mixer models. At 2.5 THz variations of the bandwidth with the LO power rather agrees with the hot-spot mixer model than with any of the homogeneous bolometric models whereas an increase of the bandwidth at low LO frequencies plausibly evidences non-bolometric direct interaction of magnetic vortices with the radiation field