Nanoscale Gap-Plasmon-Enhanced Superconducting Photon Detectors at Single-Photon Level.

Yang, Jing-Wei; Peng, Tzu-Yu; Clarke, Daniel D A; Bello, Frank Daniel; Chen, Jia-Wern; Yeh, Hao-Chen; Syong, Wei-Ren; Liang, Chi-Te et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

With a growing demand for detecting light at the single-photon level in various fields, researchers are focused on optimizing the performance of superconducting single-photon detectors (SSPDs) by using multiple approaches. However, input light coupling for visible light has remained a challenge in the development of efficient SSPDs. To overcome these limitations, we developed a novel system that integrates NbN superconducting microwire photon detectors (SMPDs) with gap-plasmon resonators to improve the photon detection efficiency to 98% while preserving all detector performance features, such as polarization insensitivity. The plasmonic SMPDs exhibit a hot-belt effect that generates a nonlinear photoresponse in the visible range operated at 9 K (∼0.64<i>T</i><sub>c</sub>), resulting in a 233-fold increase in phonon-electron interaction factor (γ) compared to pristine SMPDs at resonance under CW illumination. These findings open up new opportunities for ultrasensitive single-photon detection in areas like quantum information processing, quantum optics, imaging, and sensing at visible wavelengths.