Maximum photon-number separation with higher photon numbers and more pixels

Determine how much further the separation of photon-number encodings in a series nanowire detector can be increased by detecting higher mean photon numbers and using more detector pixels.

Background

The paper demonstrates event-by-event photon-number assignment in a three-pixel series-connected superconducting nanowire single-photon detector using dual triggering on the rising and falling edges of the output pulse. The falling-edge delay maps pulse amplitude, and therefore photon number, onto a time interval that separates one-, two-, and three-photon events.

The conclusion identifies scaling the approach to higher mean photon numbers and larger pixel counts as unresolved. Increasing either parameter could bring the detector into a partially resolved regime with greater overlap between neighboring photon-number events. The authors therefore point to further tailoring of the detector circuit and output pulse as a means of maximizing the spacing of the photon-number encoding.