Figure 14: LCO dynamical diffraction pattern. The effect of laser excitation on the diffraction pattern is shown by displaying diffraction difference frames at different times after the arrival of the laser pulse. These frames were obtained by referencing diffraction patterns at each time delay to a negative-time frame by subtraction. Bright regions indicate positive intensity and dark regions show the negative intensity. Laser excitation results in a movement of the Bragg spot profiles along the c-axis direction to lower momentum transfer values. The laser-induced changes reach a maximum around 120 ps and relax back to equilibrium on longer time scale (1 ns). These patterns were obtained at room temperature for a laser fluence of 20.6 mJ/cm2.