Fast and efficient detection of a single photon with hole-patterned superconductor microstrips

Abstract

In this Letter, we report on pattern engineering in superconducting microstrips to achieve a fast and efficient detection of a single-photon over a large detection area. The proposed detector is composed of hole-patterned superconductor microstrips fabricated with a 5-nm-thick amorphous molybdenum silicide film. It exhibits a saturated internal detection efficiency at 1550 nm with a negligible dark count rate and a recovery time of 9 ns with a large detection area (50 × 50 μm2). The simulation reveals that the holes patterned in the superconductor microstrip stimulate the nucleation of the vortex, which constitutes a major key to achieving the efficient detection of photons. This work paves the way for the facile and prolonged regulation of vortex nucleation in superconductors, which shows promise for developing high-performance large-area superconductor single-photon detectors.

Effective suppression of dark counts in superconducting microstructures with grid of pinholes in a magnetic field

“…To summarise, we investigated the properties of a superconducting microwire pinhole meander, showing single-photon detection and dark-count properties that are significantly different from those of normal microwire meander detectors [14][15][16]24]. This pinhole meander exhibits a robust critical current against magnetic field within a certain magnetic-field window spanning ≈±16 mT [25,30].…”

“…It is well known that defects, such as artificial holes, can trap vortices and hinder their motion, thereby increasing the current-carrying capability of a superconducting film [19][20][21][22][23]. This phenomenon can be used for changing the properties of superconducting microwires and detectors [24]. The effect of a single hole on the critical current of a NbN-based microbridge was recently investigated, and corresponding experiments showed that the application of an external magnetic field B has only a weak effect on the critical current I c , leading to a plateau in I c (B).…”

Characterization of a superconducting microstrip single-photon detector shunted with an external resistor

“…In 2021, Xu et al reported that an NbN SMSPD irradiated using helium ions achieved nearsaturation detection at a wavelength of 1550 nm, with an SDE exceeding 90% [17]. Furthermore, numerous novel findings were raised in the field of SMSPDs, such as those related to materials [18], geometric layout design [19,20], and optical lithography fabrication [18,21,22].…”