BOLOMETRIC RESPONSE OF OPTICALLY THICK SUPERCONDUCTING FILMS

A one-dimensional heat conduction model is established to interpret th e chopping frequency dependence of the bolometric response of opticall y thick superconducting films. The key feature of this model is that i t 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 ex pressions of the thermal conductance, thermal capacitance, radiation a bsorption efficiency and response time constant of the bolometric syst em have been deduced, where the influences of the film, substrate and the heat conduction boundaries are all considered.