A scalable multi-photon coincidence detector based on superconducting nanowires

Abstract

Coincidence detection of single photons is crucial in numerous quantum technologies and usually requires multiple time-resolved single-photon detectors. However, the electronic readout becomes a major challenge when the measurement basis scales to large numbers of spatial modes. Here, we address this problem by introducing a two-terminal coincidence detector that enables scalable readout of an array of detector segments based on superconducting nanowire microstrip transmission line. Exploiting timing logic, we demonstrate a sixteen-element detector that resolves all 136 possible single-photon and two-photon coincidence events. We further explore the pulse shapes of the detector output and resolve up to four-photon events in a four-element device, giving the detector photon-number-resolving capability. This new detector architecture and operating scheme will be particularly useful for multi-photon coincidence detection in large-scale photonic integrated circuits.

Broadband on-chip single-photon spectrometer

“…Future improvement also requires the optimization of the device design to improve the system detection efficiency (see Supplementary Note 1 and 4) and remove the non-Gaussian tails in the histogram results to increase the dynamic range (see Supplementary Note 7). It is also notable that although this work focuses on the single-photon detection regime, our on-chip spectrometer can also be extended to study two-photon absorption events 28 and thus could be an important tool for characterizing spectrally entangled photon pairs. Moreover, our design can be easily extended to mid-infrared waveband, where lots of important and fast-emerging applications reside, such as remote sensing and single-photon lidar.…”

“…On the other hand, superconducting nanowire single-photon detectors (SNSPDs) 12,13 have recently emerged as one of the best alternatives, outperforming the semiconductor counterparts in all aspects with near-unity efficiency, high speed, low jitter, low dark counts [14][15][16][17][18] and the capability of on-chip integration with integrated nanophotonic circuits [19][20][21][22][23][24][25][26][27][28] . However, these detectors operate in a strong non-linear modeonly informing the presence or absence of photons -and thus cannot discriminate the energy or provide the spectral information of the detected photons.…”

Single-Photon Single-Flux Coupled Detectors

“…Detection of single-photons is essential to applications such as optical communications, astronomical measurements, and quantum-information processing. Superconducting nanowire single-photon detectors (SNSPDs) are prominent tools for these applications because of their > 90% detection efficiencies, near GHz count rates, few picosecond timing jitter, broad spectral sensitivity from ultra-violet to infrared wavelengths, and sub-Hz dark count rates [1,2,3].…”

Accurate Detection of Arbitrary Photon Statistics

“…Also, the multi-pixel detectors offer very limited reconfigurability and complicate channel balancing. Recent on-chip integration of independent on-off cryogenic detectors represents a promising direction [29,31,35], which has yet to be tested for various classical and, particularly, nonclassical sources.…”

“…Furthermore, the multi-channel scheme allows for straightforward on-chip integration. Therefore, further improvements in speed, efficiency and compactness can be expected using superconducting single-photon detectors [26,29,31] coupled with waveguide technology [41][42][43].…”