Preliminary measurements of the conductivity in high Tc 1-2-3 type copper oxide crystals after a short pulse of intense visible radiation show the lifetime of the photo-excited state is enhanced by nearly three orders of magnitude. The goal is to test two hypotheses: (1) the excitation process causes phase separation of the photo-induced carriers into metallic regions or droplets and (2) a photo-induced high temperature superconducting state is present in these phase separated metallic regions. Steady state and fast transient spectroscopy will be undertaken on several high Tc materials using strip-line configurations as a function of temperature and magnetic field.
