Two-temperature model of a thin-film superconducting bolometer

This paper reports on a simple description of a thin-film bolometer operating at low temperature. In addition to modeling the cooling of the film by the substrate, the authors introduce the dynamics of the electron-phonon system in the relaxation-time approximation. The transient resistive response of YBaCuO films exposed to nanosecond optical pulses is analyzed to obtain an effective electron-phonon relaxation time whose temperature dependence is close to T-3. Finally, the observed steady-state response of the film to light is discussed in the framework of the two-temperature model