Abstract
We investigate thermal properties of a single-photon detector capable of unit internal detection efficiency. Using an independent calibration of the coupling losses, we determine the absolute optical power absorbed by the film and, via resistive superconductor thermometry, the temperature dependence of the thermal resistance of the film. In principle, this approach permits simultaneous measurement of the electron-phonon and phonon-escape contributions to the energy relaxation, which in our case is ambiguous because of the similar temperature dependencies. We analyze with a two-temperature model and impose an upper bound on the ratio of electron and phonon heat capacities in , which is surprisingly close to a recent theoretical lower bound for the same quantity in similar devices.
- Received 7 October 2018
- Revised 4 December 2018
DOI:https://doi.org/10.1103/PhysRevApplied.10.064063
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