Optical Nonlinearities in VO₂ Nanoparticles and Thin Films

Journal Article · Thu Jan 01 04:00:00 EST 2004 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.1826232· OSTI ID:1003436

Lopez, R. ^[1]; Feldman, Leonard C. ^[1]; Boatner, Lynn A ^[2]; Haynes, Tony E ^[2]

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1. Vanderbilt University
2. ORNL

Z-scan and pump-probe measurements with ultrafast, 800 nm laser pulses were used to compare the ultrafast optical nonlinearities of VO{sub 2} nanoparticles and thin films in both semiconducting and metallic states. In the metallic state, both the nanocrystals and thin films exhibit a positive, intensity-dependent nonlinear index of refraction. However, the nonlinear effects are relatively larger in the VO{sub 2} nanocrystals, which also reveal a saturable nonlinear absorption. When the semiconductor-to-metal phase transition is induced by the laser pulse, VO{sub 2} thin films exhibit a negative equivalent nonlinear index of refraction while the nanocrystals exhibit a smaller but still positive index. Both the VO{sub 2} nanocrystals and thin films undergo the phase transition within 120 fs.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1003436
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 22 Vol. 85; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
LASERS
REFRACTIVE INDEX
THIN FILMS