Figure 7: Time-resolved diffraction in BSCCO. (a) Diffraction intensity change of the (00) rod at different polarizations in optimally doped Bi2212. The laser fluence was 20 mJ/cm2, and the temperature was 50 K. The electron probing was kept along [ ] (Figure 2(b)), and is the angle of polarization away from the probing direction (controlled by rotation of a half-wave plate). The dotted lines (and also those in panels (b) to (d)) show the fits to an apparent exponential decay. (b) Diffraction intensity change of the (00) rod, from the same sample, obtained with the optical polarization being parallel to the electron probing. By rotating the crystal, the time-dependent change was measured for the two zone axes (Figures 2(a) and 2(b)). (c) Diffraction intensity change of the (00) rod for an underdoped Bi2212 sample (  K), at two temperatures and two polarizations. (d) Diffraction intensity change obtained from a three-layered, optimally doped Bi2223 sample at 45 K for two polarizations.