2025/07/10 by Vivek Khichar, V. A. Chirayath, Khichar, Vivek +13
Materials Science · Physics and Astronomy · #Chemical and Physical Properties of Materials #FOS: Physical sciences #Optical Coatings and Gratings #Physics of Superconductivity and Magnetism #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2507.07866
openalex publication_date 2025/07/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report on the temperature-dependent optical response of thin films of YBa2Cu3O7-δ (YBCO) in the visible spectral range under cryogenic conditions. Specifically, we observe an increase in transmittance near the superconducting transition temperature (Tc), which saturates within a few kelvins below Tc. The increase in transmittance is accompanied by a corresponding decrease in reflectance as the temperature drops below Tc, and both quantities track the superconducting phase transition. Changes in transmittance are found to be wavelength dependent, with the maximum variation occurring at 633 nm and minimal at 450 nm. These observations establish a correlation between the variation in optical response and the superconducting phase transition, even in the visible regime. The results of our experiment highlight the potential for using non-contact optical measurements to determine Tc. The effect can be explained using the two-fluid model, which can account for the observed temperature and wavelength dependence of the transmittance of the superconducting thin films.