An energy-sensitive interfacial-superconductor photodetector

Abstract The investigation of photon response in the superconducting state of interfacial superconductors holds both fundamental and practical significance, yet it remains largely unexplored. Here, we report an energy-sensitive photodetector utilizing a microstrip patterned on an interfacial superconductor (LaAlO 3 /KTaO 3 ), achieving photon response spanning from visible to near-infrared wavelengths. Remarkably, the photon response pulse amplitude at the same wavelength is linearly related to the incident light power, showing a unique detection capability that is different from the conventional superconducting single-photon detectors. Our results suggest that the energy-sensitive characteristic arises from the Kondo effect observed in the two-dimensional electron gases of the interfacial superconductor, wherein incident photons alter the normal resistance. This study broadens the potential applications of interface superconductors and presents a versatile approach for the advancement of energy-sensitive photodetection technologies.