Observation of bolometric optical response in superconducting microwave meander lines

Abstract

The change in the resonant frequency of YBa2Cu3O7−x meander lines under thermal and optical perturbations was used to determine whether pair breaking effects are induced either by bolometric or nonbolometric responses. The frequency-domain measurements were performed by monitoring the change of both the microwave resonance mode frequency and frequency width. The variation of the resonant frequency induced by two external perturbations shows a quadratic dependence on each perturbation in the range of 0.28Xc–0.56Xc. A perturbation to the fourth dependence is observed above 0.63Xc, where Xc is either the critical temperature or the critical optical pulse energy at which resonance can no longer be distinguished. The results suggest that the photoresponse of the superconducting meander line is bolometric due to laser heating.