Enhancement of photon detection in superconducting nanowire single photon detector exposed to oscillating magnetic field

Abstract

We measured the photon count rate (PCR) and dark count rate (DCR) of a superconducting nanowire single photon detector (SNSPD) exposed to either a DC magnetic field (up to 60 mT) or to a low-amplitude oscillating field (0.12–0.48 mT, up to 50 kHz). In both cases, the results show an increase in the PCR and the DCR as the DC field or the frequency of the AC field increase. However, the ratio DCR/(PCR + DCR) increases significantly with an increasing DC field, whereas this ratio is approximately constant as the frequency of the AC field increases up to frequencies in the kHz regime. The results suggest a more favorable effect of AC fields on the operation of the SNSPD.

Current dependence of the negative magnetoresistance in superconducting NbN nanowires

“…5 nm films of NbN were deposited on a R-plane sapphire substrate, 500 thick, using AJA DC reactive magnetron sputtering. For achieving high-quality films, the substrate was first heated to for two hours and then cooled to 750 at which the sputtering took place 22 , 23 . The sputtering was done at a rate of 0.075 Å per second with a 99.95% pure Nb target in a gas mixture of Nitrogen (8%) and Argon with a total pressure of .…”

Nanoscale Gap-Plasmon-Enhanced Superconducting Photon Detectors at Single-Photon Level

“…Most SSPDs are optimized for high detection efficiency in the near-infrared range. ,− To date, there have yet to be reports on optimizing SSPDs for visible light due to the challenge of input light coupling for visible light remaining an obstacle. To overcome this challenge, we have designed external gap plasmon nanoresonators using particle-on-film nanocavities, resulting in a giant nonlinear photoresponse operated at 9 K via GPR.…”

“…The enhancement factor of photoresponse is defined by γ, which is an order of magnitude higher than recently reported SSPDs through diverse structural optimizations (see Table S4). ,− This enhancement predominately results from the localized heating induced by gap plasmons, causing a transition from the superconducting state to the normal state. In addition, the designed plasmonic NbN SMPDs have multiple advantages, including polarization independence, low kinetic inductance, large active area, and high photoresponse in the visible spectrum.…”