Vanadium dioxide is an intensely studied material, since it goes through an insulator-metal transition at a critical temperature just above room temperature at 340~K. The dramatic change in conductivity and the easily accessible transition temperature makes it an attractive material for novel technologies. Thin films of VO2 have a reversible transition without any significant degradation in contrast, and depending on the microstructure of the films, the properties of the transition are tunable. In this work, I study the dynamics of the insulator-transition in thin films grown on different substrates using a pump-probe configuration. The energy needed to trigger the transition, as well as the time constants of the change in reflectivity are affected by the strain in the VO2 films. I also characterized the samples using Raman spectroscopy and XRD measurements in order to identify what underlies the differences in behavior. Finally, in collaboration with Dr. Yamaguchi\u27s group at RPI, I show that it is possible to trigger the transition using a THz pulse that directly pumps energy into the lattice, and at lower energies than needed to pump films by photoinducing the electrons across the band gap
