Type: Article
Publication Date: 2018-12-28
Citations: 8
DOI: https://doi.org/10.1103/physrevapplied.10.064063
Thermal properties are an important ingredient of a superconducting detector of radiation, determining how an impinging photon's energy is shared inside the detector. This study uses independent calibration of the radiation coupling losses and resistive superconductor thermometry to investigate the thermal resistance of a NbN film, the working element of a superconducting single-photon detector. An upper bound on the ratio of electron and phonon heat capacities in NbN is established, which is surprisingly close to the recent theoretical $l\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}w\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}r$ bound for this quantity. The results will contribute to the strategy for identifying further materials for such detectors.