Ultrafast Dynamics of the VO2 Insulator-to-Metal Transition Observed by Nondegenerate Pump-Probe SpectroscopyN. F. Brady, K. Appavoo, M. Seo, J. Nag, R. P. Prasankumar, R. F. Haglund and D. J. HiltonEPJ Web of Conferences, 41 (2013) 03006DOI: https://doi.org/10.1051/epjconf/20134103006