Optical response in a high-T_c YBCO nanowire

We demonstrate the optical response from high-T_c superconductor nanowires at temperatures above that of liquid nitrogen. Using hard oxide A l 2 O 3 as a mask material, we achieved miniaturized YB a 2 C u 3 O 7 − δ wires with widths nearing 100 nm, a significant milestone for highly sensitive photodetectors. We investigated the photoresponse of these nanowires at temperatures almost an order of magnitude higher than previously reported, under varying temperature and bias current conditions. Our findings reveal a strong correlation between the optical response and the critical parameters of the superconductor, with peak optical responses close to the critical values of temperature and bias current density. Nanowire response to wavelengths from visible to near-infrared range demonstrated a pronounced absorption maximum at temperatures below T_c. These results lay a solid foundation for the development of high-T_c superconductor nanowire single-photon detectors, understanding of nanoscale high-T_c superconductor structure optical behavior, and advancing the prospects of quantum technologies.