Ultrafast nonlinear dynamics in thin GaN films studied by femtosecond digital holography N. Šiaulys, A. Urniežius, T. Stanislauskas, T. Malinauskas, V. Kudriašov and A. Melninkaitis EPJ Web of Conferences, 41 (2013) 04007 Published online: 13 March 2013 DOI: 10.1051/epjconf/20134104007