Vector imaging of supercurrent flow in YBa2Cu3O7−δ thin films using terahertz radiation

We demonstrated the vector mapping of the supercurrent flow in YBa2Cu3O7−δ thin films using a terahertz (THz) radiation imaging system. A wire-grid polarizer was employed to detect the vector components of the THz radiation. The two THz radiation images obtained through the polarizer tilted by +45° and −45° with respect to the detector’s orientation were successfully transferred into the vector image of the supercurrent distribution. The observed distributions in the current-biased and the vortex-penetrated films were qualitatively explained using Bean’s critical-state model [E. H. Brandt and M. Indenbom, Phys. Rev. B 48, 12893 (1993)].