  We propose and demonstrate a spatial partition method for the high-frequency
photo-response of superconducting devices correlated with inductive and
resistive changes in microwave impedance. Using a laser scanning microscope, we
show that resistive losses are mainly produced by local defects at microstrip
edges and by intergrain weak links in the high-temperature superconducting
material. These defects initiate nonlinear high-frequency response due to
overcritical current densities and entry of vortices.
