Quantum detector tomography of a 2×2 multi-pixel array of superconducting nanowire single photon detectors

Abstract

We demonstrate and verify quantum detector tomography of a superconducting nanowire singlephoton detector (SNSPD) in a multiplexing scheme which permits measurement of up to 71000 photons per input pulse. We reconstruct the positive operator valued measure (POVM) of this device in the low photon-number regime, and use the extracted parameters to show the POVMs spanning the whole dynamic range of the device. We verify this by finding the mean photon number of a bright state. Our work shows that a reliable quantum description of large-scale SNSPD devices is possible, and should be applicable to other multiplexing configurations.

Information extraction in photon-counting experiments

“…Here we compare four different multiplexing schemes (five detectors) in total: a commercially available four-pixel SNSPD array, a 4-bin (and 8-bin) time-multiplexed detector (TMD), a 4-bin spatially-multiplexed detector, and finally a 10-bin timemultiplexed loop-detector, which relies on a logarithmic time-multiplexing architecture enabling a high dynamicrange over 120 dB [14] (all shown in Figs. 1(a [20]. The errors are based on assuming 5% uncertainty in the amplitudes of the coherent states.…”

Quantum characteristics and applications of multi‐pixel photon counter

“…Instead, QDT can be used to characterize the quantum features of PNRDs. 15,18,19 According to the Born rule, the output probability p m of a detector is induced by…”

“…Conventional calibration methods such as radiant power calibration 16 and correlated calibration techniques 17 can only verify the standard parameters such as detection efficiency, cross talk, dead time and dark counts, which cannot fully characterize the performance of the PNRDs. Instead, QDT can be used to characterize the quantum features of PNRDs 15,18,19 . According to the Born rule, the output probability p m of a detector is induced by where p m is the probability that the detector's output is m .…”

Quantum detector tomography of a high dynamic-range superconducting nanowire single-photon detector

“…This allows one to state the probability that a specific number of photons were incident, given a particular detector outcome, know as a positive operator valued measure (POVM). Quantum detector tomography has been carried out for single-pixel SNDPD devices [29,30], as well as temporally- [25] and spatially- [31] multiplexed SNSPDs.…”

“…In this paper, we demonstrate tomographic reconstruction of a multiplexed detector with a Hilbert space up to 10 5 . Building on [31], we carry out the full reconstruction of up to 11 outcomes of a multiplexed detector. This result is used to verify a model of how the POVMs behave at much higher input photon numbers, which mitigates the effect of limited computational power when reconstructing the large matrices which result from such high-dimensional reconstructions.…”