Wide-band highspeed Nb and YBaCuO detectors

The physical limitations on the response time and the nature of nonequilibrium detection of radiation were investigated for Nb and YBCO film in a wide spectral range from millimeter to near-infrared wavelengths. In the case of ideal heat removal from the film, the detection mechanism is connected with an electron heating effect which is not selective over a wide spectral interval. For Nb, the dependence of the response time on the electron mean free path l and temperature T is τ∝T^-2l ^-1. The values of detectivity D* and τ are 3×10¹¹ W^-1 Hz^1/2 cm and 5×10^-9 s at T=1.6 K, respectively. For YBCO film the τ value of 1-2 ps at T=77 K was obtained; the NEP value of 3×10^-11 W-Hz^-1/2 can be obtained at T=77 K in the case of the optimal film matching to the radiation