In-situ creation and control of Josephson junctions with a laser beam

Abstract

We propose the use of a laser beam tightly focused on a superconducting strip to create a Josephson junction by the photothermal effect. The critical current of this junction can be easily controlled by the laser intensity. We show that a periodic modulation of the intensity substantially changes the dynamic properties of the junction and results in the appearance of Shapiro steps without microwave radiation. The experimental realization of optically driven Josephson junctions may open a way for the ultrafast creation and switching of complex patterns of superconducting devices with tunable geometry and current-phase relations.