Nonequilibrium THz conductivity of Bi2Sr2CaCu2O8+δ

Using high-sensitivity visible-pump/THz-probe spectroscopy we investigate the dynamics of the complex optical conductivity, sigma(omega) = sigma(1)(omega) + isigma(2)(omega), in optimally-doped Bi2Sr2CaCu2O8+delta films directly after photoexcitation. The photoinduced change in the imaginary part Deltasigma(2), indicative of a reduction in the superconducting condensate density, saturates at higher laser-fluences and shows a complete destruction of the condensate. (C) 2004 Elsevier B.V. All rights reserved.