High resolution magneto-optical study of superconducting thin films and devices

Magneto-optical (MO) studies have been carried out on superconducting thin films. In this paper, we give the features that determine the signal to noise ratio of the imaging system and optimize the image contrast. The flux distribution of vortices in thin films are given, which determines the requirements to satisfy for vortex visualization using a MO layer. Images of partial flux penetration through the slit of a DC SQUID are presented. Flux focusing efficiency can be deduced from these Images.