Bolometric response of optically thick superconducting films

A one-dimensional heat conduction model is established to interpret the chopping frequency dependence of the bolometric response of optically thick superconducting films. The key feature of this model is that it takes into account the thermal boundary couductance of both the film/substrate and the substrate/heat-sink interfaces. The model is found to be suitable for both the strong and weak thermal coupling cases. By comparing the results with a simplified bolometric model, explicit expressions of the thermal conductance, thermal capacitance, radiation absorption efficiency and response time constant of the bolometric system have been deduced, where the influences of the film, substrate and the heat conduction boundaries are all considered.