  The "colossal magnetoresistive" (CMR) manganites are highly correlated
systems with a strong coupling between spin, charge, orbital, and lattice
degrees of freedom, which leads to complex phase diagrams and to the
coexistence of various forms of ordering. For example, nanoscale charge/orbital
ordering (CO) fluctuations appear to cooperate with Jahn-Teller (JT)
distortions of the MnO$_{6} octahedra in CMR manganites and compete with the
electron itinerancy favored by double exchange. However, access to the ordered
dynamical state has been challenging, mostly due to intrinsic experimental
difficulties in measuring fast short-range correlations. Here, we report on a
strongly damped low-energy collective mode originating from fast short-range CO
fluctuations in La}$_{0.67}Ca$_{0.33}Mn{O}$_{3}(LCMO) single crystal and thin
films. We elucidate the collective mode in terms of its dispersion relation and
dependence on average A-site ion radius, r$_{A}, and hole-doping concentration.
Our results show for the first time that dynamical short-range CO correlations
in CMR manganites can be detected with high momentum resolution by coherent
ultrafast optical techniques.
