Optical nonlinearities and the ultrafast phase transition of VO 2 nanoparticles and thin films

Rene Lopez, Richard F. Haglund, Leonard C. Feldman, Lynn A. Boatner, Tony E. Haynes

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Z-scan and pump-probe measurements with ultra-fast 800 nm laser pulses were used to compare the ultrafast third-order optical nonlinearities of VO 2 nanoparticles and thin films in both semiconducting and metallic states. It is found that when the samples are hold at temperatures above 67 °C in their metallic state, both nanocrystals and thin films present a positive intensity-dependent nonlinear index of refraction. In this metallic state the nanocrystals exhibit a saturable optical nonlinearity and enhancement of the nonlinear effects larger than those found in thin films. Below the transition temperature, the optical nonlinearities are more complex, since they arise from alterations in the VO 2 that arise both from the phase transition and from unrelated third-order nonlinear effects. Under these conditions, thin films exhibit a complete reversal to a negative nonlinear index of refraction while the nanocrystals, remarkably, show a smaller but still positive index. Pump-probe measurements on vanadium dioxide nanocrystals and thin films show they both exhibit an ultrafast response, undergoing the phase transition induced by a single laser shot in less than 120 fs. The speed of the solid-solid transformation, along with the striking reversal of the nonlinear properties across the phase transition, puts vanadium dioxide in a unique category among nonlinear materials.

Original languageEnglish
Title of host publicationUltrafast Phenomena in Semiconductors and Nanostructure Materials X
DOIs
Publication statusPublished - May 23 2006
EventUltrafast Phenomena in Semiconductors and Nanostructure Materials X - San Jose, CA, United States
Duration: Jan 23 2006Jan 25 2006

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6118
ISSN (Print)0277-786X

Other

OtherUltrafast Phenomena in Semiconductors and Nanostructure Materials X
CountryUnited States
CitySan Jose, CA
Period1/23/061/25/06

    Fingerprint

Keywords

  • Nanoparticles
  • Nonlinear optics
  • Phase transition
  • Switching
  • Ultrafast
  • Vanadium dioxide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Lopez, R., Haglund, R. F., Feldman, L. C., Boatner, L. A., & Haynes, T. E. (2006). Optical nonlinearities and the ultrafast phase transition of VO 2 nanoparticles and thin films. In Ultrafast Phenomena in Semiconductors and Nanostructure Materials X [61180O] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 6118). https://doi.org/10.1117/12.640977