We study the ultrafast insulator-to-metal transition in nanoparticles of VO2, obtained by ion implantation and self-assembly in silica. The nonmagnetic, strongly correlated compound VO2 undergoes a reversible phase transition, which can be photoinduced on an ultrafast time scale. In the nanoparticles, prompt formation of the metallic state results in the appearance of surface-plasmon resonance. We achieve large, ultrafast enhancement of optical absorption in the near-infrared spectral region that encompasses the wavelength range for optical-fiber communications. One can further tailor the response of the nanoparticles by controlling their shape.
© 2005 Optical Society of America
(160.4670) Materials : Optical materials
(160.4760) Materials : Optical properties
(300.6500) Spectroscopy : Spectroscopy, time-resolved
(320.7130) Ultrafast optics : Ultrafast processes in condensed matter, including semiconductors
(320.7150) Ultrafast optics : Ultrafast spectroscopy
Matteo Rini, Andrea Cavalleri, Robert W. Schoenlein, René López, Leonard C. Feldman, Richard F. Haglund, Jr., Lynn A. Boatner, and Tony E. Haynes, "Photoinduced phase transition in VO2 nanocrystals: ultrafast control of surface-plasmon resonance," Opt. Lett. 30, 558-560 (2005)