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

TL;DR

This paper introduces a method to create and control Josephson junctions in superconductors using a focused laser beam, enabling rapid, tunable, and optically driven superconducting device patterns.

Contribution

It demonstrates a novel photothermal technique for in-situ creation and dynamic control of Josephson junctions with laser intensity modulation.

Findings

Laser-induced Josephson junctions exhibit tunable critical currents.

Periodic laser modulation induces Shapiro steps without microwave radiation.

Optical control enables rapid switching and patterning of superconducting devices.

Abstract

We propose the use of a laser beam tightly focused on a superconducting strip to create a Josephson junction by 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 ultra-fast creation and switching of complex patterns of superconducting devices with tunable geometry and current-phase relations.