Insulator to metal transition induced by surface plasmon polaritons in VO2/Au thin films.

We report on a new mechanism capable of inducing the insulator-metal transition (IMT) in VO2 via surface plasmon polaritons (SPP). Our theoretical model predicts that for a bilayer Au-VO2 sample an enhanced electromagnetic energy density at the Au-VO2 interface will occur at 1064nm laser wavelength when SPPs are excited in the Au layer. This effect can assist the IMT in the VO2 layer and at the same time, the SPP absorption can be used to detect it. Changes in the optical properties of the VO2 thin layer in such structure can be observed in the reflected light in Kretschmann configuration, via a shift in the nadir location due to light absorption at resonance. This optical mechanism occurs at 2mW threshold transition energies and fully saturates at 5mW.

Surface plasmon resonance modulation in nanopatterned Au gratings by the insulator-metal transition in vanadium dioxide films.

Correlated experimental and simulation studies on the modulation of Surface Plasmon Polaritons (SPP) in Au/VO2 bilayers are presented. The modification of the SPP wave vector by the thermally-induced insulator-to-metal phase transition (IMT) in VO2 was investigated by measuring the optical reflectivity of the sample. Reflectivity changes are observed for VO2 when transitioning between the insulating and metallic states, enabling modulation of the SPP in the Au layer by the thermally induced IMT in the VO2 layer. Since the IMT can also be optically induced using ultrafast laser pulses, we postulate the viability of SPP ultrafast modulation for sensing or control.