Detection and storage of femtosecond laser pulse signals by optical magnetic-flux-generation in a YBCO thin film loop

We studied the optical creation and modulation of magnetic flux quanta in a YBa2Cu3O7-delta thin film loop by observing terahertz emission excited wit h femtosecond laser pulses. The magnetic flux is created and modulated in t he loops with a polarity controlled by means of optical supercurrent modula tion. The results suggest a possible application of the superconductive loo p as an optical flux-trap memory for the detection and storage of the femto second optical signals. The mechanism for the creation of the magnetic flux is discussed in relation to the current distribution in the loop.