Mar 20, 20231 min
The detection of individual quanta of light is essential for a range of applications, and so superconducting-nanowire single-photon detectors (SNSPDs) have become increasingly important due to their high detection efficiency and signal-to-noise ratio. However, usual SNSPDs require costly cryocoolers to operate. A new study has reported the fabrication of two types of high-temperature superconducting nanowires. This expands the family of materials available for SNSPD technology beyond the usual liquid helium temperature limit, and further research may even lead to operation at even higher temperatures.
Abstract:
The detection of individual quanta of light is important for quantum communication, fluorescence lifetime imaging, remote sensing and more. Due to their high detection efficiency, exceptional signal-to-noise ratio and fast recovery times, superconducting-nanowire single-photon detectors (SNSPDs) have become a critical component in these applications. However, the operation of conventional SNSPDs requires costly cryocoolers. Here we report the fabrication of two types of high-temperature superconducting nanowires. We observe linear scaling of the photon count rate on the radiation power at the telecommunications wavelength of 1.5 μm and thereby reveal single-photon operation. SNSPDs made from thin flakes of Bi2Sr2CaCu2O8+δ exhibit a single-photon response up to 25 K, and for SNSPDs from La1.55Sr0.45CuO4/La2CuO4 bilayer films, this response is observed up to 8 K. While the underlying detection mechanism is not fully understood yet, our work expands the family of materials for SNSPD technology beyond the liquid helium temperature limit and suggests that even higher operation temperatures may be reached using other high-temperature superconductors.