Detection of Pulsed Terahertz Radiation by a Superconducting Bolometer in the Process of Parametric Down-Conversion

The statistical distributions of output signals and their derivatives have been investigated for a superconducting bolometer exposed to weak photon pulses at a frequency of 1 THz. The terahertz pulses were generated via strongly nondegenerate parametric down-conversion in a LiNbO $${}_{3}$$ crystal cooled to 4.8 K, under conditions of pumping the crystal with laser pulses of 28 ps duration. Various scenarios of the superconducting bolometer’s response to excitation by a small number of terahertz photons are discussed.