The thermally-coupled imager: A scalable readout architecture for superconducting nanowire single photon detectors

TL;DR

The paper introduces the thermally-coupled imager (TCI), a scalable readout architecture for superconducting nanowire single-photon detectors, demonstrated on a 32x32 array capable of high-speed photon imaging and localization.

Contribution

The TCI architecture enables scalable, independent operation of large SNSPD arrays with minimal readout lines, demonstrated on a 1024-pixel array.

Findings

Successfully demonstrated a 32x32 SNSPD array

Achieved photon imaging at 373 nm with high distinguishability

Operated at 9.6 Mcps with only four microwave readout lines

Abstract

Although superconducting nanowire single-photon detectors (SNSPDs) are a promising technology for quantum optics, metrology, and astronomy, they currently lack a readout architecture that is scalable to the megapixel regime and beyond. In this work, we have designed and demonstrated such an architecture for SNSPDs, called the thermally-coupled imager (TCI). The TCI uses a combination of time-of-flight delay lines and thermal coupling to create a scalable architecture that can scale to large array sizes, allows neighboring detectors to operate independently, and requires only four microwave readout lines to operate no matter the size of the array. We give an overview of how the architecture functions, and demonstrate a proof-of-concept $32\times32$ imaging array. The array was able to image a free-space focused spot at 373 nm, count at 9.6 Mcps, and resolve photon location with greater than 99.83\% distinguishability.