Effects of Surface Plasmonic Electric Field Enhancements on Thin Film Vanadium Dioxide’s Insulator to Metal Transition.

We investigate the effect that the surface plasmonic electric field enhancement will have on insulator to metal transition (IMT) in vanadium dioxide (VO₂) films. We have observed using this method that we can photo-induced the IMT with laser powers of 5mW. The possibility of surface plasmons inducing an IMT in a VO₂ film could be the basis of a new type of efficient photo switch or sensor. Our theoretical model predicts that in a glass/Au/VO₂ thin film structure, a strong electric field enhancement of 89 times the field at the glass-Au interface will occur in VO₂ at 1064nm laser wavelength. A model of the SP electric field enhancement effect in VO₂ coupled with the differences in fractional amounts of VO₂ converted between metal and insulator is being used to guide the design of experimental samples and from experimental results fits to within 50%. The study involves two different samples with structures consisting of a 31nm Au film and 10nm VO₂ film and a 31nm Au film and 5nm VO₂, both deposited on a glass substrate.