KINETIC INDUCTANCE AND PENETRATION DEPTH OF THIN SUPERCONDUCTING FILMS MEASURED BY THZ-PULSE SPECTROSCOPY

We measure the transmission of THz pulses through thin films of YBa2Cu3O7-delta at temperatures between 10 and 300 K. The pulses possess a usable bandwidth extending from approximately 0.1 to 1.5 THz (3.3-50 cm-1). Below T(c) we observe pulse reshaping caused by the kinetic inductance of the superconducting charge carriers. From transmission data, we extract values of the London penetration depth, as a function of temperature, and find that they agree well with a functional form [lambda(0)/lambda(T)]2 = 1 - (T/T(c))alpha, where lambda(0) = 148 nm and or = 2.