Optical response in a high-TcYBCO nanowire

We demonstrate the optical response from high-Tc superconductor nanowires at temperatures above that of liquid nitrogen. Using hard oxide Al2O3 as a mask material, we achieved miniaturized YBa2Cu3O7−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 Tc. These results lay a solid foundation for the development of high-Tc superconductor nanowire single-photon detectors, understanding of nanoscale high-Tc superconductor structure optical behavior, and advancing the prospects of quantum technologies.