Abstract
Superconducting nanowire single photon detectors (SNSPD) functionality is based on the local suppression of the superconducting order parameter upon photon absorption, causing a change in resistance which can be detected as a DC voltage pulse. Finding the size and the profile of the superconducting order parameter suppression area (the so-called “hot-spot”) experimentally is a challenging task. Here, we report the results of a quantum detector tomography on micron-length SNSPDs. The high internal detection efficiency of our SNSPDs allowed us to extract single and double photon efficiencies from the count rate vs radiation power dependence and extract hot-spot interaction length. We investigated a series of SNSPD samples made of NbN films with different sheet resistance and a MoSi film, with various widths of the stripe. The experimental results confirmed that regardless of the material or the film resistance, the hot-spot interaction length coincides with the strip width which is a promising feature for making a 2-photon counter with high fidelity.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
