Timing Jitter in NbN Superconducting Microstrip Single-Photon Detector

Physical Review Applied. 2020. Vol. 14. No. 4. P. 044041.

Vodolazov D. Y., Manova N., Korneeva Y., Korneev A.

We experimentally study timing jitter of single-photon detection by NbN superconducting strips with
width w ranging from 190 nm to 3 μm. We find that timing jitter of both narrow (190 nm) and micron- wide strips is about 40 ps at currents where internal detection efficiency η saturates and it is close to our instrumental jitter. We also calculate intrinsic timing jitter in wide strips using the modified time- dependent Ginzburg-Landau equation coupled with a two-temperature model.We find that with increasing width the intrinsic timing jitter increases and the effect is most considerable at currents where a rapid growth of η changes to saturation. We relate it with complicated vortex and antivortex dynamics, which depends on a photon’s absorption site across the strip and its width. The model also predicts that at current close to depairing current the intrinsic timing jitter of a wide strip could be about ?/kBTc (Tc is a critical temperature of superconductor), i.e., the same as for a narrow strip.

Keywords: nonequilibrium superconductivity