Single-particle plasmon resonance spectroscopy of phase transition in vanadium dioxide.

We demonstrate thermally controlled plasmon resonance modulation of single gold nanoparticles on vanadium dioxide thin films by performing dark-field spectroscopy measurements at different temperatures. The plasmon resonance of the nanoparticles exhibits a significant blueshift in the visible range when the vanadium dioxide film undergoes its insulator-to-metal phase transition around 67 °C. More importantly, the resonance shift shows a clear hysteresis, mirroring the behavior of the vanadium dioxide film. At a fixed wavelength, the scattering intensity of Au particles also shows a hysteretic behavior decorated with an overshoot before (after) the insulator-metal (metal-insulator) phase transition of the vanadium dioxide film, suggesting that the nanoparticle is probing local variations in the phase transition.