Mitigation of rf-induced critical-current shifts in NbN superconducting nanowire single-photon detectors for trapped-ion readout

Abstract

The integration of superconducting nanowire single-photon detectors (SNSPDs) for state readout in trapped-ion quantum processors is hindered by their sensitivity to electromagnetic interference from ion-trapping radio-frequency (rf) fields. We demonstrate a comprehensive mitigation strategy for niobium nitride (NbN) SNSPDs that combines a conducting, optically transparent tin-doped indium oxide (ITO) shield with a nanowire of optimized geometry. Our results show that a 300-nm-wide nanowire exhibits greater resilience to rf fields compared to a 100-nm-wide device, sustaining a higher relative critical current at increased rf amplitudes. We also implement a phase-coherent active rf cancellation technique that recovers 92% of the detector’s unperturbed critical current under a 2π×25MHz rf field. Based on these findings, we demonstrate the possibility of engineering SNSPDs for compatibility with the rf environments of surface electrode traps. This combined approach provides a robust strategy for integrating SNSPDs into trapped-ion systems, which is a critical step towards scalable quantum information processing.

Source-reported materials — not catalogue approval

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