Bolometric Response of High-Tc Superconducting Detectors to Optical Pulses and Continuous Waves

Abstract

This work presents a thermal analysis on predicting the temperature increase and the voltage response of high-Tc superconducting bolometers. Two heat transfer models, that is, the surface heating model and the heat generation model considering the skin depth, are introduced and compared. The surface heating model is found to be valid only for situations where the skin depth is much smaller than the film thickness. To consider the thermal boundary resistance between film and substrate, a radiation-boundary-condition model based on acoustic mismatch model (AMM) and an interfacial-layer model (ILM) are employed. The thermal boundary resistance significantly influences the voltage response. Additionally, several common substrates are examined. SrTiO3 (100) or LaAlO3 (100) is a better substrate for high-Tc superconducting bolometers. One interesting finding was that when compared with experimental data, all the theoretical values from the present study as well as the other previously theoretical treatment overestimate the voltage response near the transition temperature.