An energy-sensitive interfacial-superconductor photodetector

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 (LaAlO3/KTaO3), 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.