@article {155176, title = {Characterizing concentrated, multiply scattering, and actively driven fluorescent systems with confocal differential dynamic microscopy}, journal = {Physical Review Letters}, volume = {108}, number = {21}, year = {2012}, pages = {218103}, abstract = {We introduce confocal differential dynamic microscopy (ConDDM), a new technique yielding information comparable to that given by light scattering but in dense, opaque, fluorescent samples of micron-sized objects that cannot be probed easily with other existing techniques. We measure the correct wave vector q-dependent structure and hydrodynamic factors of concentrated hard-sphere-like colloids. We characterize concentrated swimming bacteria, observing ballistic motion in the bulk and a new compressed-exponential scaling of dynamics, and determine the velocity distribution; by contrast, near the coverslip, dynamics scale differently, suggesting that bacterial motion near surfaces fundamentally differs from that of freely swimming organisms.}, url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.108.218103}, author = {Lu, Peter J. and Giavazzi, Fabio and Angelini, Thomas E. and Zaccarelli, Emanuela and Jargstorff, Frank and Schofield, Andrew B. and Wilking, James N. and Romanowsky, Mark B. and Weitz, David A and Cerbino, Roberto} }