Driven by studies on quantum cryptography and nuclear decays, we developed an iridium-based single-photon superconducting detector as a fast detector for operation in the 0.1 K environment.
Due to the peculiar characteristics of iridium thin film, which has a Tc of 120-150 mK and resistivity to electron mean free path product that makes it suitable for low resistivity nanowires, we fabricated and studied SPSD samples in two types of geometries: small squares and high aspect ratio nanowires.
According to the detector models, measurements of electron-phonon coupling in metallic iridium are a key parameter to be studied to accelerate the detectors.
A systematic series of measurements with different sizes and geometries of electron-phonon conductivity is underway.
We present here the measurements, methodology and models, and preliminary results available.

Keywords: Transition Edge Sensor, Superconductivity, Single photon