Optical Single-Photon Detection in Micrometer-Scale NbN Bridges

Abstract

We demonstrate experimentally that single photon detection can be achieved in micron-wide NbN bridges, with widths ranging from 0.53 µm to 5.15 µm and for photon-wavelengths from 408 nm to 1550 nm. The microbridges are biased with a dc current close to the experimental critical current, which is estimated to be about 50% of the theoretically expected depairing current. These results offer an alternative to the standard superconducting single-photon detectors (SSPDs), based on nanometer scale nanowires implemented in a long meandering structure. The results are consistent with improved theoretical modelling based on the theory of non-equilibrium superconductivity including the vortex-assisted mechanism of initial dissipation.

Photon-triggered instability in the flux flow regime of a strongly disordered superconducting strip

“…In this respect, the presented results are not very promising from an application point of view. This result is in contrast to the single-photon response in micron-wide bridges in the vortexfree Meissner state, biased at currents close to the depairing current [30].…”

Different Single-Photon Response of Wide and Narrow Superconducting MoxSi1−x Strips

“…Specifically, the ZV model requires the bias current in the bridge to roughly exceed a half of the depairing current. Previously, these conditions were experimentally satisfied in wide and short NbN bridges studied by Korneeva et al 3 .…”

Температурные Зависимости Критических Параметров Неоднородных Сверхпроводящих Пленок

“…Изучение транспортных [1,2] и магнитных [3,4] характеристик сверхпроводящих материалов и структур не теряет своей актуальности. Особенно перспективно исследование сверхпроводящих пленок [4][5][6][7][8][9][10][11], так как на их основе создаются датчики для регистрации единичных фотонов [12][13][14], элементы для электроники [15] и т. д. При моделировании критического состояния сверхпроводящей пленки необходимо учитывать ее неоднородность по толщине [9][10][11], а также влияние подложки и окружающей среды на ее свойства. В работах [6][7][8] в рамках теории Гинзбурга−Ландау (ГЛ) рассматривалось влияние границ пленки на ее сверхпроводящие свойства, которое задавалось через граничные условия общего вида на параметр порядка [16].…”