Temperature-controlled surface plasmon resonance in VO_2 nanorods

The optical properties of ${\mathrm{VO}}_2$ nanoparticles formed in an amorphous ${\mathrm{SiO}}_2$ host by stoichiometric ion implantation of vanadium and oxygen and thermal annealing have been determined and correlated with the particle size and morphology. The results show that that the temperature-controlled semiconductor-to-metal phase transition of the ${\mathrm{VO}}_2$ nanophase precipitates turns on the classical surface plasmon resonance, with specific features that depend on the size and aspect ratio of the ${\mathrm{VO}}_2$ particles. This effect improves the optical contrast between the metallic and semiconducting states in the near-IR region of the spectrum as a result of dielectric confinement that is due to the ${\mathrm{SiO}}_2$ host. A fiber-optic application is demonstrated, as is the ability to control the characteristics of the phase transition by using ion implantation to dope the ${\mathrm{VO}}_2$ nanoparticles with tungsten or titanium ions.